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Invoice Ninja API and MCP server

Invoice Ninja's API is only on the Ninja Pro plan and above, and it takes an API token and code you write and host. Sign in to Invoice Ninja once in your own Cloud Browser, and your AI agent does the work there for you. The same tools work over MCP for agents and as a REST API for scripts.

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Not affiliated with Invoice Ninja.

Invoice Ninja has no API for this. So we run one for you.

Invoice Ninja's own API, a GitHub MCP server and Cotlet compared
What you need Invoice Ninja's APIGitHub MCP serverCotlet
Invoices, quotes, payments No Partly Yes, 14 tools
Acts as you, signed in 24/7 No No Yes, Cloud Browser
Fixed for you when Invoice Ninja changes N/A No Yes, tested every 6h
Runs with your laptop off N/A No Yes, hosted

Checked Oct 14, 2026. Sources: Invoice Ninja: Pricing and plan comparison · Invoice Ninja API Reference · Invoice Ninja Docs: Invoices API · Invoice Ninja on Zapier: triggers and actions

Your own Cloud Browser, on 24/7. Sign in once. We keep it connected.

  1. 01Sign in to Invoice Ninja in your own Cloud Browser

  2. 02Connect it for your agents

  3. 03Cotlet keeps it signed in and working

How do I connect Invoice Ninja to Claude, ChatGPT or my code?

AI agents connect over MCP, scripts call the REST API. Both reach the same 14 tools with one API key.

For AI agents: MCP

Add Cotlet to your agent once. Invoice Ninja and every other app you connect show up as its tools.

  • Claude
  • ChatGPT
  • OpenClaw
  • Hermes
  • GrokBot
  • Cursor
  • n8n
  • Any MCP client
  1. 1

    Add Cotlet to your agent

    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"

    Paste the snippet for your client. The same server and key serve every app you connect, so you do this once.

For scripts: REST API

Every tool is an endpoint under /api/v1/invoice-ninja with its own method and path, such as POST /api/v1/invoice-ninja/clients/{client_id}/invoices, with the same API key. Our open-source repo has ready scripts to start from.

REST API docs

What can the Invoice Ninja API and MCP server do?

14 tools on your own Invoice Ninja account. Agents call them as operations of the MCP tools invoice_ninja_read and invoice_ninja_write; scripts call each one at its own REST endpoint, with the same inputs and answers.

API reference
Invoice Ninja tools in Cotlet's MCP server and REST API
Tool What it does Access
list_clients Clients with ID, contact, currency, paid to date and outstanding balance. read
list_invoices Invoices with client, status, dates, amount and balance, newest first. read
get_invoice One invoice with line items, contacts, linked payments and the email history. read
list_quotes Quotes with client, status, valid-until date and amount. read
list_payments Payments with client, date, amount, type, reference and the invoices they were applied to. read
list_products Products from your product library with description and unit price. read
create_client Add a client with one contact, optionally with the currency to bill in. write
create_invoice Create a draft invoice for a client with line items, dates and notes. write
create_quote Create a draft quote for a client with line items and a valid-until date. write
send_invoice Email an invoice, or a reminder for it, to the contacts that receive it. writeasks first
send_quote Email a quote to the contacts that receive it. writeasks first
convert_quote_to_invoice Turn an approved quote into an invoice and link the two. writeasks first
record_payment Record money received against an invoice, with date, type and bank reference. writeasks first
cancel_invoice Cancel a sent invoice: its balance goes to zero and the client balance drops. writeasks first

Scroll the table for all 14 tools.

Ask in plain words. Your agent does the rest.

All Invoice Ninja use cases

Is it safe to connect Invoice Ninja?

You sign in yourself in your own Cloud Browser, we never save your password, and anything that reaches your readers waits for your OK. The browser profile is encrypted in the EU. Independent scanners grade cotlet.dev A+.

Security overview

How much do the Invoice Ninja API and MCP server cost?

One price for both: a tool call costs the same over MCP or REST. Free 7-day trial with 2,000 credits, no card needed. Then one-time credit packs, no subscription, valid 12 months. Most calls use 25 credits, and your Cloud Browser uses 50 credits a day while Invoice Ninja is enabled for agents, so 20 calls a day come to 550 credits.

See full pricing
Cotlet credit packs: price, credits and calls at 25 credits each
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.

Questions

Does Invoice Ninja have an 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.

How do I get access?

Sign up free, open Invoice Ninja under Integrations in the console and press Request access. Your free trial starts with your account, no card needed.

Is the MCP server different from the API?

No, only the way in. Cotlet builds each integration as a REST API and puts an MCP server on top, so both have the same 14 tools, the same inputs and answers, one API key and one price. AI agents such as Claude, ChatGPT or Cursor use MCP; scripts, cron jobs and HTTP steps in n8n, Make or Zapier use the REST API.

What is the Cloud Browser?

Your own Chrome that Cotlet runs for you in the EU, around the clock. You open it from the console, sign in to Invoice Ninja yourself and press Enable for agents. Your agent's calls go through it, from its IP with its cookies, so Invoice Ninja sees the browser you signed in with. Password saving is off and the profile is stored encrypted with AES-256-GCM.

Can my agent act without asking me?

Not on anything that reaches other people: send_invoice, send_quote, convert_quote_to_invoice, record_payment, cancel_invoice wait for your OK by default. You can switch that off per tool for scheduled runs.

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.

Should I use a Invoice Ninja MCP server from GitHub instead?

Pick one if you want the code on your own computer and do not mind the upkeep: you install it, sign it in and fix it when Invoice Ninja changes. Pick Cotlet if you want it hosted and kept working for you.

Can I use it in n8n, Make or Zapier?

Yes. Add https://cotlet.dev/mcp/v1 in n8n's MCP Client node, or call the REST endpoints from an HTTP step in Make or Zapier.

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 Cotlet affiliated with Invoice Ninja?

No. Cotlet is independent and not affiliated with Invoice Ninja.

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