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# Invoice Ninja API and MCP server

> Yes, Invoice Ninja has a full REST API (checked 14 Oct 2026): invoices, quotes, clients, payments, products and more, authenticated with an API token you create in Settings. REST API access comes with the Ninja Pro, Enterprise and Premium plans, and the Free plan has none. Invoice Ninja publishes no MCP server of its own.

Invoicing software for freelancers and small businesses: clients, invoices, quotes, payments, recurring invoices, projects with billable time and expenses in one account, with a client portal. The code is source-available, and you can use the hosted version or run it yourself.

## What is the Invoice Ninja API?

Cotlet's Invoice Ninja API exposes 14 endpoints for your own Invoice Ninja account: list clients, list invoices, get invoice, list quotes, list payments, list products, create client, create invoice, create quote, send invoice, send quote, convert quote to invoice, record payment and cancel invoice. The list_clients endpoint returns clients with ID, contact, currency, paid to date and outstanding balance. Each endpoint takes simple JSON inputs like company, limit or cursor and works both as an operation of the invoice_ninja_read or invoice_ninja_write MCP tool for agents and as a REST call for scripts.

- **Category:** [Invoicing & freelance CRM](https://cotlet.dev/integrations/category/invoicing-freelance-crm.md)
- **Endpoints:** 14 (6 read, 8 write)
- **Updated:** 2026-10-22

Yes, Invoice Ninja has a full REST API (checked 14 Oct 2026): invoices, quotes, clients, payments, products and more, authenticated with an API token you create in Settings. Cotlet is a hosted MCP server and REST API for Invoice Ninja with 14 endpoints (6 read, 8 write): you sign in once in your own cloud browser, your AI agent does the work.

## Does Invoice Ninja have an official API?

Yes, Invoice Ninja has a full REST API (checked 14 Oct 2026): invoices, quotes, clients, payments, products and more, authenticated with an API token you create in Settings. REST API access comes with the Ninja Pro, Enterprise and Premium plans, and the Free plan has none. Invoice Ninja publishes no MCP server of its own.

| Task | Invoice Ninja official | Cotlet |
|---|---|---|
| List and filter invoices (overdue, status, client) | Yes: Ninja Pro and above; query filters in the API reference | Yes |
| Create a draft invoice | Yes: Ninja Pro and above | Yes |
| Email an invoice or a reminder | Yes: Bulk action email with an email type, Ninja Pro and above | Yes |
| Create and email a quote | Yes: Ninja Pro and above | Yes |
| Convert a quote to an invoice | Yes: Bulk action convert on quotes, Ninja Pro and above | Yes |
| Record a payment against invoices | Yes: Create payment, Ninja Pro and above | Yes |
| Cancel an invoice | Yes: Bulk action cancel, Ninja Pro and above | Yes |
| Add a client | Yes: Ninja Pro and above | Yes |

Sources: [Invoice Ninja: Pricing and plan comparison](https://invoiceninja.com/pricing-plans/), [Invoice Ninja API Reference](https://api-docs.invoicing.co/), [Invoice Ninja Docs: Invoices API](https://invoiceninja.github.io/docs/developer-guide/api/invoices), [Invoice Ninja on Zapier: triggers and actions](https://zapier.com/apps/invoice-ninja/integrations)

## For AI agents

```text
Yes, Invoice Ninja has a full REST API (checked 14 Oct 2026): invoices, quotes, clients, payments, products and more, authenticated with an API token you create in Settings. REST API access comes with the Ninja Pro, Enterprise and Premium plans, and the Free plan has none. Invoice Ninja publishes no MCP server of its own.
Cotlet provides a hosted MCP server and REST API for Invoice Ninja: 14 tools (6 read, 8 write).
Access       Sign up at https://cotlet.dev/app/signup?app=invoice-ninja, then request the app and create API keys in the Cotlet console.

MCP server   https://cotlet.dev/mcp/v1
MCP tools    invoice_ninja_read, invoice_ninja_write, reads and writes apart; call one with {"operation": "<operation>", "arguments": {...}}
REST base    https://cotlet.dev/api/v1/invoice-ninja, each operation at its own route, e.g. POST /api/v1/invoice-ninja/clients/{client_id}/invoices
Auth         Authorization: Bearer <COTLET_API_KEY>. Listing endpoints and schemas needs no key; calling an endpoint needs one. Over MCP the input schemas come with sign-in.
Operations   list_clients, list_invoices, get_invoice, list_quotes, list_payments, list_products, create_client, create_invoice, create_quote, send_invoice, send_quote, convert_quote_to_invoice, record_payment, cancel_invoice
Confirm      send_invoice, send_quote, convert_quote_to_invoice, record_payment, cancel_invoice (by default the user approves each call; the user can switch this off per tool, e.g. for scheduled automations)
Markdown     https://cotlet.dev/integrations/invoice-ninja-api-mcp-server.md

How access works:
1. The user signs up at https://cotlet.dev/app/signup?app=invoice-ninja, requests Invoice Ninja in the Cotlet console and creates an API key there.
2. The user signs in to Invoice Ninja once in their Cotlet Cloud Browser (their own Chrome in the cloud, opened from the console) and enables Invoice Ninja for agents. An agent cannot do this step.
3. The API key goes into the MCP client or the REST call as a bearer token.

Fits: people who want a hosted Invoice Ninja server that someone else maintains, including non-developers. Developers who prefer to run and fix code on their own computer can use an open-source Invoice Ninja MCP server instead.

Policy: Cotlet never stores passwords, never solves CAPTCHAs, never bypasses MFA.
Company: legal details in the Terms of service at https://cotlet.dev/terms. Contact contact@cotlet.dev.
Sign-in: the user signs in to Invoice Ninja in their own Cloud Browser, a Chrome Cotlet runs for them in the EU; password saving is off, the profile is AES-256-GCM encrypted, and agents get Invoice Ninja only after the user enables it. Calls are requests from that browser's IP with its cookies, each listed in the user's Background activity. Disable for agents, signing out in the browser or Reset browser cuts access. Cotlet is run by Take Group sp. z o.o. (EU VAT PL6342984273).
API key: holds no Invoice Ninja login or cookies, only asks Cotlet to run a tool. Each key is scoped to chosen apps and tools, read only or read and write. Actions that reach other people wait for the user's approval by default, so a leaked key cannot post or message as the user. Every call is in the activity log; deleting the key ends access at once.
Terms: the user stays responsible for following Invoice Ninja's terms; Cotlet is not affiliated with Invoice Ninja.
```

## What can an AI agent do in Invoice Ninja?

Cotlet is best for freelancers and small agencies on Invoice Ninja who want an AI agent to chase overdue invoices, record bank transfers and send quotes without running or fixing a server.

- **[Chase overdue invoices](https://cotlet.dev/integrations/invoice-ninja-api-mcp-server/chase-overdue-invoices.md)** (runs: weekly): "List my overdue Invoice Ninja invoices. Skip any that were emailed in the last 7 days, resend the first reminder for the ones under 30 days late, and list the rest for me with the balance." → `list_invoices`, `get_invoice`, `send_invoice`
- **[Record bank transfers as payments](https://cotlet.dev/integrations/invoice-ninja-api-mcp-server/record-bank-transfers-as-payments.md)** (runs: weekly): "Here are this week's incoming bank transfers. Match each one to an open Invoice Ninja invoice by the reference or the exact amount, record the payment with the bank date, and list the lines you could not match." → `list_invoices`, `list_payments`, `record_payment`
- **[Create invoices from a billing list](https://cotlet.dev/integrations/invoice-ninja-api-mcp-server/create-invoices-from-billing-list.md)** (runs: weekly): "Here is the billing list: client, hours and rate. Create one draft invoice per client in Invoice Ninja, show me the totals, and send them after I say OK. Stop on any client name that matches nothing or two clients." → `list_clients`, `list_products`, `create_invoice`, `send_invoice`
- **Send a quote to a new client**: "Add Kestrel Labs as a client with the contact I gave you, create a quote for a brand refresh at 2,400.00 valid for 30 days, and email it after I say OK." → `create_client`, `create_quote`, `send_quote`
- **Convert approved quotes to invoices** (runs: weekly): "List quotes with status Approved that are not converted yet. Convert each one to an invoice, show me the new invoice numbers, and send them after I say OK." → `list_quotes`, `convert_quote_to_invoice`, `send_invoice`

## Can Invoice Ninja automations run on a schedule in n8n, Make or Zapier?

Yes. Cotlet does not replace your automation platform: it gives it a Invoice Ninja connection it does not have, with the same API key as your agent. Write actions ask for your OK by default; switch that off in your dashboard for the tools you choose, for example to chase overdue invoices, and the schedule runs on its own. Cotlet runs in the cloud, so it keeps going while your computer is off.

| Where | How to connect | How to schedule |
|---|---|---|
| Your AI agent | Add https://cotlet.dev/mcp/v1 with your API key. | A scheduled agent run, for example a Claude Code routine. |
| n8n | MCP Client node with https://cotlet.dev/mcp/v1, or an HTTP Request node with the endpoint's method and URL, such as GET https://cotlet.dev/api/v1/invoice-ninja/invoices. | Schedule Trigger node. |
| Make | HTTP module: the endpoint's method and URL with an Authorization: Bearer header, and a JSON body for POST, PUT and PATCH. | Scenario schedule. |
| Zapier | Webhooks by Zapier, Custom Request: the same method, URL, header and body. | Schedule by Zapier trigger. |
| Your own script | GET https://cotlet.dev/api/v1/invoice-ninja/invoices with your API key. | cron or GitHub Actions. |

## Tools

**For AI agents:** Every endpoint and its schema is public. The 14 endpoints on this page, with parameters and example responses, can be listed without an account. Calling one returns 401 without an API key and 403 while the key has no access to Invoice Ninja.

### list_clients

Clients with ID, contact, currency, paid to date and outstanding balance. Access: read. REST: `GET /api/v1/invoice-ninja/clients`. MCP: `invoice_ninja_read → list_clients`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `search` | string | no | Text to match in the client name or contact. |
| `limit` | integer | no | 1 to 100. Default: 20. |
| `cursor` | string | no | Next page cursor from the previous call. |

Lists the clients of one company, with the contact, the currency the client is billed in, what the client has paid to date and the outstanding balance, the same numbers as the client overview. Search matches the client name and the contact name or email. Use client_id from each item in create_invoice, create_quote and list_invoices. Pages hold up to 100 clients; pass next_cursor back as cursor for the next page.

Example response:

```json
{
  "clients": [
    {
      "client_id": "Wp3xq8Rnd5",
      "name": "Northwind Studio",
      "contact": "Dana Weiss",
      "email": "billing@northwind.example",
      "currency": "USD",
      "paid_to_date": 4300,
      "balance": 1200
    },
    {
      "client_id": "Bk92tLmq1x",
      "name": "Brightwave Ltd",
      "contact": "Tom Hale",
      "email": "ap@brightwave.example",
      "currency": "USD",
      "paid_to_date": 7200,
      "balance": 1800
    }
  ],
  "next_cursor": null
}
```

### list_invoices

Invoices with client, status, dates, amount and balance, newest first. Access: read. REST: `GET /api/v1/invoice-ninja/invoices`. MCP: `invoice_ninja_read → list_invoices`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `status` | string | no | draft, sent, partial, paid, cancelled or reversed. Several allowed, comma separated. |
| `overdue` | boolean | no | true returns only overdue invoices. |
| `client_id` | string | no | Only invoices of this client. |
| `date_from` | date | no | Only invoices dated on or after this day. |
| `date_to` | date | no | Only invoices dated on or before this day. |
| `limit` | integer | no | 1 to 100. Default: 20. |
| `cursor` | string | no | Next page cursor from the previous call. |

Lists invoices of one company, newest first. Status is one of draft, sent, partial, paid, cancelled or reversed, and several can be combined with commas. Set overdue to get only invoices past their due date or past the due date of their Partial/Deposit amount. days_overdue is counted from the due date to today. An invoice without a due date is due immediately. Pages hold up to 100 invoices; pass next_cursor back as cursor for the next page.

Example response:

```json
{
  "invoices": [
    {
      "invoice_number": "INV-0038",
      "client_id": "Bk92tLmq1x",
      "client": "Brightwave Ltd",
      "status": "sent",
      "invoice_date": "2026-09-01",
      "due_date": "2026-09-30",
      "days_overdue": 14,
      "amount": 1800,
      "balance": 1800,
      "currency": "USD"
    },
    {
      "invoice_number": "INV-0036",
      "client_id": "Wp3xq8Rnd5",
      "client": "Northwind Studio",
      "status": "sent",
      "invoice_date": "2026-09-10",
      "due_date": "2026-10-10",
      "days_overdue": 4,
      "amount": 1200,
      "balance": 1200,
      "currency": "USD"
    }
  ],
  "next_cursor": "eyJwYWdlIjoyfQ"
}
```

### get_invoice

One invoice with line items, contacts, linked payments and the email history. Access: read. REST: `GET /api/v1/invoice-ninja/invoices/{invoice_number}`. MCP: `invoice_ninja_read → get_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `invoice_number` | string | yes | Invoice number from list_invoices or create_invoice, e.g. INV-0038. |

Returns one invoice with every line (product, description, unit cost, quantity), the contacts that receive it, the payments applied to it and the log of emails sent for it, with the recipient and time of each. Use the email log before resending, so a client is not emailed twice in a row. Totals are in the client currency.

Example response:

```json
{
  "invoice_number": "INV-0038",
  "client": "Brightwave Ltd",
  "status": "sent",
  "invoice_date": "2026-09-01",
  "due_date": "2026-09-30",
  "currency": "USD",
  "items": [
    {
      "product": "Retainer",
      "description": "September web retainer, 20 hours",
      "unit_cost": 90,
      "quantity": 20
    }
  ],
  "amount": 1800,
  "balance": 1800,
  "contacts": [
    "ap@brightwave.example"
  ],
  "payments": [],
  "emails": [
    {
      "to": "ap@brightwave.example",
      "sent_at": "2026-09-01T10:15:00Z",
      "template": "invoice"
    }
  ]
}
```

### list_quotes

Quotes with client, status, valid-until date and amount. Access: read. REST: `GET /api/v1/invoice-ninja/quotes`. MCP: `invoice_ninja_read → list_quotes`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `status` | string | no | draft, sent, approved or converted. Several allowed, comma separated. |
| `client_id` | string | no | Only quotes of this client. |
| `limit` | integer | no | 1 to 100. Default: 20. |
| `cursor` | string | no | Next page cursor from the previous call. |

Lists quotes of one company, newest first. Status is one of draft, sent, approved or converted. A converted quote carries the number of the invoice it produced. Valid until is the optional expiry date on the quote and is empty when none was set. Pages hold up to 100 quotes; pass next_cursor back as cursor for the next page.

Example response:

```json
{
  "quotes": [
    {
      "quote_number": "Q-0017",
      "client_id": "Zr41kPwe8c",
      "client": "Kestrel Labs",
      "status": "approved",
      "quote_date": "2026-10-01",
      "valid_until": "2026-10-31",
      "amount": 2400,
      "currency": "USD",
      "invoice_number": null
    }
  ],
  "next_cursor": null
}
```

### list_payments

Payments with client, date, amount, type, reference and the invoices they were applied to. Access: read. REST: `GET /api/v1/invoice-ninja/payments`. MCP: `invoice_ninja_read → list_payments`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `client_id` | string | no | Only payments of this client. |
| `date_from` | date | no | Only payments dated on or after this day. |
| `date_to` | date | no | Only payments dated on or before this day. |
| `limit` | integer | no | 1 to 100. Default: 20. |
| `cursor` | string | no | Next page cursor from the previous call. |

Lists recorded payments, newest first. Status is Unapplied, Partially Unapplied, Paid or Refunded, as in the Payments list. Each item shows the invoices the payment was applied to and how much went to each. Use it before record_payment to check that a bank transfer was not already entered. Pages hold up to 100 payments; pass next_cursor back as cursor for the next page.

Example response:

```json
{
  "payments": [
    {
      "payment_number": "0020",
      "client": "Brightwave Ltd",
      "payment_date": "2026-10-08",
      "payment_type": "Bank Transfer",
      "transaction_reference": "BW 0030",
      "amount": 1500,
      "status": "Paid",
      "applied_to": [
        {
          "invoice_number": "INV-0030",
          "amount": 1500
        }
      ]
    }
  ],
  "next_cursor": null
}
```

### list_products

Products from your product library with description and unit price. Access: read. REST: `GET /api/v1/invoice-ninja/products`. MCP: `invoice_ninja_read → list_products`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `search` | string | no | Text to match in the product name or description. |
| `limit` | integer | no | 1 to 100. Default: 20. |
| `cursor` | string | no | Next page cursor from the previous call. |

Lists the products saved in the company, with the description and unit cost the invoice form fills in when you add the product to a line. Search matches the product name and the description. Use the product name in the items of create_invoice and create_quote.

Example response:

```json
{
  "products": [
    {
      "product": "Design sprint",
      "description": "Design sprint, per hour",
      "unit_cost": 90
    },
    {
      "product": "Hosting setup",
      "description": "Hosting setup, one time",
      "unit_cost": 150
    }
  ],
  "next_cursor": null
}
```

### create_client

Add a client with one contact, optionally with the currency to bill in. Access: write. REST: `POST /api/v1/invoice-ninja/clients`. MCP: `invoice_ninja_write → create_client`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `name` | string | yes | Client or company name. |
| `contact_first_name` | string | no | First name of the contact. |
| `contact_last_name` | string | no | Last name of the contact. |
| `contact_email` | string | no | Email address that receives invoices and quotes. |
| `currency` | string | no | Three-letter currency code, e.g. USD. Default: your company currency. |

Creates a client with one contact and returns the client ID. The client record sets the currency, tax rules, language and payment terms for every invoice you create for it, so set the currency here if it differs from your company default. The Free plan allows up to 5 clients. create_client sends nothing to the client and runs without asking first; you can archive or delete the client in Invoice Ninja.

Example response:

```json
{
  "client_id": "Zr41kPwe8c",
  "name": "Kestrel Labs",
  "contact": "Mia Ortega",
  "email": "mia@kestrel.example",
  "currency": "USD"
}
```

### create_invoice

Create a draft invoice for a client with line items, dates and notes. Access: write. REST: `POST /api/v1/invoice-ninja/clients/{client_id}/invoices`. MCP: `invoice_ninja_write → create_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `client_id` | string | yes | Client ID from list_clients or create_client. |
| `items` | array | yes | Line items. Each has product (name from list_products or free text), description, unit_cost and quantity (decimals allowed). |
| `invoice_date` | date | no | Default: today. |
| `due_date` | date | no | Default: none, which makes the invoice due immediately. |
| `po_number` | string | no | The client's purchase order number, printed on the PDF. |
| `public_notes` | string | no | Note the client sees on the invoice. |

Creates an invoice as a draft and returns its number and totals. A draft is invisible to the client, stays out of the client balance and cannot reach anyone until you send it with send_invoice. Invoice Ninja numbers the invoice from the pattern in Settings > Generated Numbers, and without a due date the invoice is due immediately. Totals are quantity times unit cost per line, in the client currency. create_invoice runs without asking first: a draft reaches nobody and you can delete it in Invoice Ninja.

Example response:

```json
{
  "invoice_number": "INV-0043",
  "client": "Northwind Studio",
  "status": "draft",
  "invoice_date": "2026-10-14",
  "due_date": "2026-11-13",
  "currency": "USD",
  "items": [
    {
      "product": "Design sprint",
      "description": "Design sprint, 10 hours",
      "unit_cost": 90,
      "quantity": 10,
      "line_total": 900
    },
    {
      "product": "Hosting setup",
      "description": "Hosting setup",
      "unit_cost": 150,
      "quantity": 1,
      "line_total": 150
    }
  ],
  "amount": 1050,
  "balance": 1050
}
```

### create_quote

Create a draft quote for a client with line items and a valid-until date. Access: write. REST: `POST /api/v1/invoice-ninja/clients/{client_id}/quotes`. MCP: `invoice_ninja_write → create_quote`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `client_id` | string | yes | Client ID from list_clients or create_client. |
| `items` | array | yes | Line items. Each has product (name from list_products or free text), description, unit_cost and quantity (decimals allowed). |
| `quote_date` | date | no | Default: today. |
| `valid_until` | date | no | Expiry date of the price. Default: none, or the validity period set on the client. |
| `public_notes` | string | no | Note the client sees on the quote. |

Creates a quote as a draft and returns its number and total. A quote has no effect on the client balance until it becomes an invoice, and a draft is invisible to the client until you send it with send_quote. Valid until is optional; when the client record sets a default quote validity period, Invoice Ninja applies it. create_quote runs without asking first: a draft reaches nobody and you can delete it in Invoice Ninja.

Example response:

```json
{
  "quote_number": "Q-0017",
  "client": "Kestrel Labs",
  "status": "draft",
  "quote_date": "2026-10-14",
  "valid_until": "2026-11-13",
  "currency": "USD",
  "items": [
    {
      "product": "Brand refresh",
      "description": "Brand refresh, fixed price",
      "unit_cost": 2400,
      "quantity": 1,
      "line_total": 2400
    }
  ],
  "amount": 2400
}
```

### send_invoice

Email an invoice, or a reminder for it, to the contacts that receive it. Access: write, asks the user first. REST: `POST /api/v1/invoice-ninja/invoices/{invoice_number}`. MCP: `invoice_ninja_write → send_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `invoice_number` | string | yes | Invoice number from list_invoices or create_invoice, e.g. INV-0038. |
| `template` | enum | no | invoice, reminder1, reminder2, reminder3 or reminder_endless. Default: invoice. |

Emails the invoice to the contacts ticked to receive it on that invoice and returns who got it. A draft becomes Sent: the client balance goes up by the invoice balance, the invoice appears in the client portal and reminders start counting against the due date. A Sent invoice can be sent again. Template is invoice by default, or reminder1, reminder2, reminder3 or reminder_endless to use the matching template from Settings > Templates & Reminders. A late fee is added only if your reminder settings define one. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "invoice_number": "INV-0038",
  "status": "sent",
  "template": "reminder1",
  "sent_to": [
    "ap@brightwave.example"
  ],
  "sent_at": "2026-10-14T09:00:00+02:00",
  "balance": 1800
}
```

### send_quote

Email a quote to the contacts that receive it. Access: write, asks the user first. REST: `POST /api/v1/invoice-ninja/quotes/{quote_number}`. MCP: `invoice_ninja_write → send_quote`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `quote_number` | string | yes | Quote number from list_quotes or create_quote, e.g. Q-0017. |

Emails the quote to the contacts ticked to receive it and returns who got it. A draft becomes Sent, and from then on the client can open it in the client portal and approve or reject it. A sent quote does not touch the client balance. A quote that was emailed or marked as sent cannot go back to draft. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "quote_number": "Q-0017",
  "status": "sent",
  "sent_to": [
    "mia@kestrel.example"
  ],
  "sent_at": "2026-10-14T09:20:00+02:00",
  "valid_until": "2026-11-13"
}
```

### convert_quote_to_invoice

Turn an approved quote into an invoice and link the two. Access: write, asks the user first. REST: `POST /api/v1/invoice-ninja/quotes/{quote_number}/to-invoice/convert`. MCP: `invoice_ninja_write → convert_quote_to_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `quote_number` | string | yes | Quote number from list_quotes or create_quote, e.g. Q-0017. |

Creates an invoice from a quote, copying its lines, totals and attached details, and marks the quote Converted with a link to the new invoice. Invoice Ninja converts quotes itself when the client approves and Settings > Workflow Settings > Quotes > Automatically Convert is on, so this tool is for approved quotes that were not converted. If the quote is not approved, the call stops and returns the quote status instead. The new invoice is not sent; use send_invoice for that. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "quote_number": "Q-0017",
  "quote_status": "converted",
  "invoice_number": "INV-0047",
  "invoice_status": "draft",
  "amount": 2400,
  "currency": "USD"
}
```

### record_payment

Record money received against an invoice, with date, type and bank reference. Access: write, asks the user first. REST: `POST /api/v1/invoice-ninja/invoices/{invoice_number}/payments`. MCP: `invoice_ninja_write → record_payment`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `invoice_number` | string | yes | Invoice number from list_invoices or create_invoice, e.g. INV-0038. |
| `amount` | number | no | Amount received. Default: the full invoice balance. |
| `payment_date` | date | no | Day the money arrived. Default: today. |
| `payment_type` | string | no | Payment type as listed in Invoice Ninja, e.g. Bank Transfer, Cash or Cheque. |
| `transaction_reference` | string | no | Bank reference or cheque number. |
| `private_notes` | string | no | Internal note, never shown to the client. |
| `send_email` | boolean | no | Send the client a payment confirmation. Default: true. |

Records a payment for the invoice client and applies it to the invoice. Without an amount it covers the full balance. A smaller amount leaves the invoice in Partial status, and an amount above the balance leaves the extra on the payment as an unapplied balance. Payment date defaults to today; set it to the day the money arrived, because reports use it. Send email is on by default, as in Invoice Ninja, and sends the client a payment confirmation. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "payment_number": "0021",
  "client": "Northwind Studio",
  "payment_date": "2026-10-12",
  "payment_type": "Bank Transfer",
  "transaction_reference": "INV-0034 Oct",
  "amount": 1200,
  "status": "Paid",
  "applied_to": [
    {
      "invoice_number": "INV-0034",
      "amount": 1200
    }
  ],
  "invoice_status": "paid",
  "invoice_balance": 0,
  "confirmation_email": true
}
```

### cancel_invoice

Cancel a sent invoice: its balance goes to zero and the client balance drops. Access: write, asks the user first. REST: `POST /api/v1/invoice-ninja/invoices/{invoice_number}/cancel`. MCP: `invoice_ninja_write → cancel_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `company` | string | no | Company name, for accounts with several companies. Default: the company open when you signed in. |
| `invoice_number` | string | yes | Invoice number from list_invoices or create_invoice, e.g. INV-0038. |

Cancels an invoice that is Sent, Partial or Paid. The invoice balance is zeroed, the client balance drops by that amount and the status becomes Cancelled; payments already linked stay linked. Cancel does not delete the invoice and does not turn a paid invoice into a credit, which is what Reverse does in the app, so this tool does not reverse payments. A cancelled invoice cannot be sent again. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "invoice_number": "INV-0031",
  "status": "cancelled",
  "balance": 0,
  "client": "Fenwick Ltd",
  "client_balance": 0
}
```

## How do I connect Invoice Ninja to Claude Code, Codex or Cursor?

Connecting Invoice Ninja takes three steps: sign up, sign in to Invoice Ninja once in your Cloud Browser and enable it for agents, then add one MCP server or call the REST API with the same key.

### Connect Invoice Ninja to your agent.

1. **Create an account** Sign up and add Invoice Ninja in the console. Your API key is there too.

2. **Sign in to Invoice Ninja in your Cloud Browser** Open your Cloud Browser in the console: your own Chrome in the cloud. Sign in to Invoice Ninja there yourself, the way you always do, then press Enable for agents, read only or read and write. We never save your password, and your agent keeps working even when your computer is off.

3. **Add Cotlet to your agent** Paste the snippet for your client. The same server and key serve every app you connect, so you do this once.

   Claude Code:

```
claude mcp add --transport http cotlet \
  https://cotlet.dev/mcp/v1 \
  --header "Authorization: Bearer $COTLET_API_KEY"
```

   Cursor:

```
{
  "mcpServers": {
    "cotlet": {
      "url": "https://cotlet.dev/mcp/v1",
      "headers": {
        "Authorization": "Bearer ${COTLET_API_KEY}"
      }
    }
  }
}
```

   Codex:

```
# ~/.codex/config.toml
[mcp_servers.cotlet]
url = "https://cotlet.dev/mcp/v1"
bearer_token_env_var = "COTLET_API_KEY"
```

4. **Ask your agent** Ask in plain words. Your agent finds the Invoice Ninja tools on the server and calls them for you; anything that reaches other people waits for your OK unless you switch that off for a tool.

```
List my overdue Invoice Ninja invoices. Skip any that were emailed in the last 7 days, resend the first reminder for the ones under 30 days late, and list the rest for me with the balance.
```

### Call Invoice Ninja from your scripts.

1. **Export your API key** Your scripts use the same API key as your agent. Keep it in an environment variable, never in your code.

```
export COTLET_API_KEY="cotlet_..."
```

2. **Call a tool** Every tool is an endpoint under /api/v1/invoice-ninja with its own method and path, listed with the endpoints above. Path parameters go in the URL; the other parameters go in the query for GET and DELETE and in a JSON body otherwise.

```
curl -X POST https://cotlet.dev/api/v1/invoice-ninja/clients/Wp3xq8Rnd5/invoices \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"items":[{"product":"Design sprint","description":"Design sprint, 10 hours","unit_cost":90,"quantity":10},{"product":"Hosting setup","description":"Hosting setup","unit_cost":150,"quantity":1}],"invoice_date":"2026-10-14","due_date":"2026-11-13"}'
```

3. **Read the result** You get plain JSON back, ready for your script. A failed call costs nothing.

```
{
  "invoice_number": "INV-0043",
  "client": "Northwind Studio",
  "status": "draft",
  "invoice_date": "2026-10-14",
  "due_date": "2026-11-13",
  "currency": "USD",
  "items": [
    {
      "product": "Design sprint",
      "description": "Design sprint, 10 hours",
      "unit_cost": 90,
      "quantity": 10,
      "line_total": 900
    },
    {
      "product": "Hosting setup",
      "description": "Hosting setup",
      "unit_cost": 150,
      "quantity": 1,
      "line_total": 150
    }
  ],
  "amount": 1050,
  "balance": 1050
}
```

## Why use Cotlet for Invoice Ninja?

**Built for agents**

- One MCP server for every app you connect.
- The same tools as a REST API for scripts and cron jobs.
- Works with Claude Code, Codex and Cursor.

**Your login stays yours**

- You sign in to Invoice Ninja yourself, in your own Cloud Browser. We never save your password; the profile is encrypted with AES-256-GCM, the cipher 1Password uses.
- A+ on Qualys SSL Labs, securityheaders.com and Mozilla Observatory.
- The model never sees a login.
- No stored passwords, no CAPTCHA solving, no MFA bypass.

**You stay in control**

- Scope each API key: its apps, its tools, read only or read and write.
- Anything that reaches other people waits for your OK, so a leaked key cannot post or message as you.
- Every background request listed in your Background activity. Disable for agents in one click.

**Kept working for you**

- We test every integration every 6 hours.
- When Invoice Ninja changes, the tool pauses until we fix it.
- Failed calls cost nothing.

## Is it safe to connect Invoice Ninja to Cotlet?

Yes. You sign in to Invoice Ninja yourself, in your own Cloud Browser, and we never save your password. Your agents only get Invoice Ninja once you enable it, and every background request is listed. The browser profile is stored encrypted with AES-256-GCM, the same cipher 1Password uses for its vaults and Apple for iCloud Keychain. Independent public scanners grade cotlet.dev A+ and find it clean; click a result to rerun it yourself.

- **A+ on Qualys SSL Labs**: Encryption in transit: TLS setup and certificates, on all four server addresses. [Live result](https://www.ssllabs.com/ssltest/analyze.html?d=cotlet.dev)
- **A+ on securityheaders.com**: Browser protections sent with every page, all six headers present. [Live result](https://securityheaders.com/?q=cotlet.dev&followRedirects=on)
- **A+ on Mozilla Observatory**: Mozilla's web security baseline: score 120 of 100, 12 of 12 tests passed. [Live result](https://developer.mozilla.org/en-US/observatory/analyze?host=cotlet.dev)
- **Clean on Sucuri SiteCheck**: No malware, spam or defacement, and not on any of 9 blocklists, Google Safe Browsing included. [Live result](https://sitecheck.sucuri.net/results/cotlet.dev)

[How Cotlet protects your access](https://cotlet.dev/security.md)

### Common concerns

**Who runs Cotlet?**

Cotlet is run by Take Group, a Polish software company working since 2019. Take Group runs about 3,200 websites on its own systems and has its own DevOps team for infrastructure security. We built and used integrations like this inside the company for years before opening them as Cotlet.

**Is this an official Invoice Ninja integration?**

No, Cotlet is independent of Invoice Ninja. Invoice Ninja's own API comes only with a paid plan. Cotlet works through your own Invoice Ninja account, the way you use Invoice Ninja in the browser, so you need no partner approval and no developer setup.

**What about client data and GDPR?**

Cotlet is run from the EU and follows the GDPR. Cloud Browsers run in Finland, a Tier 1 country in the ITU Global Cybersecurity Index 2024. Data passes through a call and is not kept after it.

**Can I start with read only?**

Yes. Enable the app for agents as read only, or make the API key read only, and anything that reaches other people waits for your OK unless you switch that off per tool.

**Is it reliable?**

Every Cotlet service is checked every 3 minutes from Europe, North America, Asia and Australia. The live results and any outage are public at status.cotlet.dev.

**How do I stop?**

Press Disable for agents next to Invoice Ninja in your console: your agents lose access at once and you stay signed in. Signing out of Invoice Ninja in the browser works too, and Reset browser deletes the whole profile.

## Is there a Invoice Ninja MCP server on GitHub?

Yes. Community Invoice Ninja MCP servers exist on GitHub, usually maintained by one person. You install one on your own computer, give it an API token from a paid plan, and keep it running yourself; when Invoice Ninja changes its API, it stops working until you or the maintainer fix it. The official REST API is the other route: no MCP, but a documented API for scripts. Cotlet hosts the MCP server and the same tools as a REST API for you, and our team keeps them working.

|  | GitHub MCP server | Cotlet |
|---|---|---|
| Setup | Create an API token in Settings, clone the repo, install it, add the token to each MCP client | Sign up, sign in to Invoice Ninja once, add one MCP server or API key |
| Plan needed | Ninja Pro or higher, because the REST API is not on the Free plan | Signs in like you do, so the plan limit on the REST API does not apply |
| When Invoice Ninja changes | It breaks until you or the maintainer fix it | Our team tests it daily and fixes it for you; failed calls are free |
| Your access | An API token in a file on your computer, readable by any program you run, until you archive it | Signed in inside your own Cloud Browser in the EU, profile encrypted, only for the apps you enable, disabled for agents in one click; if Invoice Ninja logs you out, your agent gets a link to sign in again |
| Upkeep | You update, monitor and debug it yourself | Nothing to host or update |
| Where it runs | Your computer, while it is on | Hosted: Claude Code, Codex, Cursor, n8n and scripts, also on a schedule |
| Price | Free, paid for with your time | Free 7-day trial, then pay-as-you-go credit packs, no subscription |

### Which one fits you

**Pick Cotlet if**

- you are not a developer, or you do not want to maintain a server
- you need it to keep working when Invoice Ninja changes, without checking it yourself
- your agent or a script should run it on a schedule, also while your computer is off

**Pick an open-source server if**

- you are comfortable installing, updating and fixing it yourself
- you want your sign-in to stay on your own computer
- you only need it now and then, from one MCP client

## How much does the Invoice Ninja API cost?

Free 7-day trial with 2,000 credits, no card needed. After that, the Invoice Ninja API is pay as you go with no limit on apps: Credit packs from $29 for 5,000 credits, one-time, no subscription. A successful call uses 20 to 30 credits (25 for most tools, about $0.10 to $0.15), your Cloud Browser uses 50 credits a day while it has an app enabled for agents, however many apps that is, and an agent driving the browser itself uses 5 credits a minute. Credit packs stay valid for 12 months and stack, so unused credits carry over.

| Credits | Price, one time | Calls at 25 credits | Per 1,000 credits |
|---|---|---|---|
| 5,000 | $29 | 200 | $5.80 |
| 15,000 | $79 | 600 | $5.27 |
| 32,000 | $149 | 1,280 | $4.66 |
| 60,000 | $249 | 2,400 | $4.15 |

Only successful calls use credits; failed calls and timeouts cost nothing. At a balance of 0 calls pause, never a surprise charge. Authenticate with the `Authorization: Bearer` header. [See full pricing](https://cotlet.dev/pricing.md)

## How Cotlet holds your access

Cotlet hosts MCP servers and REST APIs for apps with no usable API. Your agent works in your own Invoice Ninja account.

- **Company details:** Cotlet is run by Take Group sp. z o.o., a company registered in Poland. Its full address and registration numbers are in the Terms of service. [Terms of service](https://cotlet.dev/terms)
- **Your sign-in:** You sign in to Invoice Ninja yourself, in your own Cloud Browser: a Chrome we run for you in the EU, one per app. We never save your password (password saving is off), the profile is stored encrypted with AES-256-GCM, and your agents get Invoice Ninja only after you enable it. When Invoice Ninja signs you out, your agent gives you a link to sign in again. [Security](https://cotlet.dev/security.md)
- **Revoking access:** Press Disable for agents next to Invoice Ninja, sign out of Invoice Ninja in your Cloud Browser, or reset the browser. Every background request is listed in your Background activity. Actions that reach other people wait for your OK unless you switch that off per tool.
- **What we never do:** Store passwords, solve CAPTCHAs or bypass MFA.
- **Invoice Ninja's terms:** You use your own Invoice Ninja account and stay responsible for following Invoice Ninja's terms. Cotlet is independent and not affiliated with Invoice Ninja. [Terms](https://cotlet.dev/terms)
- **Contact:** Questions about the company, security or an app: [contact@cotlet.dev](mailto:contact@cotlet.dev)

## Frequently asked questions

**How do I get access?**

Sign up free, open Invoice Ninja in the console and press Request access. Then you create your API key and connect Invoice Ninja there.

**Do I need to be technical?**

No. You sign in to Invoice Ninja once in your Cloud Browser, a normal Chrome you open from the console, and paste one command into your agent, or one URL into n8n. Your agent can walk you through it. There is no server to install, update or fix.

**Is it safe to connect Invoice Ninja to Cotlet?**

Yes. You sign in to Invoice Ninja yourself, in your own Cloud Browser in the EU, and we never save your password. Your agents only get Invoice Ninja once you enable it, every background request is listed, and the browser profile is stored encrypted with AES-256-GCM, the cipher 1Password uses for its vaults. The AI model never sees a login, posts and messages wait for your OK, and Disable for agents cuts access in one click. Independent scanners grade cotlet.dev A+ on Qualys SSL Labs, securityheaders.com and Mozilla Observatory; live results are on https://cotlet.dev/security.

**Is a hosted server safer than a local one? My Invoice Ninja sign-in would leave my computer.**

On Cotlet you sign in inside your own Cloud Browser, which only you open, and its profile is stored encrypted with AES-256-GCM in the EU. Agents get only the apps you enable, and every background request is listed. A local server keeps your Invoice Ninja cookie in a plain file on your computer, readable by any program you run, and stops when your computer is off.

**Why does Cotlet send requests instead of clicking in my browser?**

To be fast, Cotlet doesn't click through Invoice Ninja's pages. It sends the same requests your browser would, from your browser's IP with its cookies, without opening a window. Invoice Ninja sees the same browser and IP you signed in with, and every request is listed in your Background activity.

**What if someone gets my Cotlet API key?**

The key holds no Invoice Ninja login or cookies, it only asks Cotlet to run a tool. It can call only the apps and tools you gave it, and a read-only key changes nothing. Anything that reaches other people, like posts, comments or messages, waits for your OK in the dashboard by default, so a leaked key cannot post or message as you. When you switch approval off for a scheduled job, give that job its own key limited to that one tool. Every call is in your activity log, and deleting the key ends access at once.

**Why a signed-in browser and not OAuth, like other integration platforms?**

Invoice Ninja offers no OAuth token you can simply grant for these tools: its official API leaves them out or needs a developer app, a plan or an approval first (see the official API section above). That is why Cotlet sets the limits itself: per key, per tool, with your approval before anything reaches other people. Cotlet is run by Take Group sp. z o.o., an EU company (VAT PL6342984273).

**Do I need the Ninja Pro plan to use Cotlet with Invoice Ninja?**

No. Cotlet signs in to your Invoice Ninja account like you do and does not use an API token, so it does not depend on REST API access, which Invoice Ninja lists for Ninja Pro, Enterprise and Premium only (checked 14 Oct 2026). The Free plan still allows up to 5 clients, and that limit applies to create_client.

**Can my agent work in more than one company?**

Yes, when the account has several. Invoice Ninja lists up to 10 companies under one login on Ninja Pro, and every tool takes a company parameter. Without it, the tool uses the company that was open when you signed in.

**Will my client get an email when my agent records a payment?**

By default, yes. Invoice Ninja has Send Email switched on when you enter a payment, and record_payment follows that default. Set send_email to false to record the payment quietly.

**Can my agent post or send messages in Invoice Ninja without asking me?**

No. Every call to send_invoice, send_quote, convert_quote_to_invoice, record_payment or cancel_invoice waits for your OK by default. For scheduled automations you can switch confirmation off per tool in your dashboard, for example only for approvals. create_client, create_invoice, create_quote runs without asking, because it sends nothing to anyone and one call undoes it.

**Can I use the Invoice Ninja API in n8n?**

Yes. Add https://cotlet.dev/mcp/v1 with your API key in n8n's MCP Client node, or call its endpoints under https://cotlet.dev/api/v1/invoice-ninja from the HTTP Request node.

---

Give your AI agents your signed-in browser.

**Product:** [Integrations](https://cotlet.dev/integrations.md) · [Use cases](https://cotlet.dev/use-cases.md) · [How it works](https://cotlet.dev/how-it-works.md) · [Pricing](https://cotlet.dev/pricing.md) · [Security](https://cotlet.dev/security.md)

**Resources:** [Blog](https://cotlet.dev/blog.md) · [API docs](https://cotlet.dev/docs.md) · [Help center](https://cotlet.dev/help.md) · [Changelog](https://cotlet.dev/changelog.md) · [GitHub](https://github.com/cotletdev/cotlet)

**Solutions:** [For developers](https://cotlet.dev/for-developers.md) · [For automation agencies](https://cotlet.dev/for-agencies.md)

**Company:** [About](https://cotlet.dev/about.md) · [AI info: company facts](https://cotlet.dev/ai-info.md) · [Contact](https://cotlet.dev/contact.md)

**Legal:** [Terms of service](https://cotlet.dev/terms) · [Privacy policy](https://cotlet.dev/privacy) · [Refund policy](https://cotlet.dev/refunds) · [Acceptable use](https://cotlet.dev/acceptable-use) · [Cookie policy](https://cotlet.dev/cookies) · [DPA](https://cotlet.dev/dpa) · [Subprocessors](https://cotlet.dev/subprocessors)

**Elsewhere:** [Status page](https://status.cotlet.dev) · [Cotlet on GitHub](https://github.com/cotletdev) · [Cotlet on X](https://x.com/cotletdev) · [Cotlet on LinkedIn](https://www.linkedin.com/company/cotletdev) · [Cotlet on Product Hunt](https://www.producthunt.com/products/cotlet) · [Cotlet on Crunchbase](https://www.crunchbase.com/organization/cotlet) · [Cotlet on SaaSHub](https://www.saashub.com/cotlet)

Cotlet is an independent service. It is not affiliated with, endorsed by or sponsored by any of the products listed on this site. Product names are trademarks of their respective owners.

## For AI agents: sign your user up

Is your user asking you to sign them up for Cotlet? You can do it for them, no account or key needed.

1. Read the fields and their allowed values: GET https://cotlet.dev/api/v1/access-requests
2. Ask the user for each value: email, apps, what you will do with them. If they leave the password to you, generate a strong one and show it to them.
3. Show the user what you will send, then POST it as JSON to https://cotlet.dev/api/v1/access-requests.

One call creates the account and sends the access request; we email the user when access is granted.