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# SnelStart API and MCP server

> Yes, but it is gated (checked 14 Oct 2026). SnelStart has a B2B API for software partners: you request a connection, get a development key and portal access, and a production integration for several users needs certification, OAuth, a webhook URL and at least five named customers. SnelStart says it is reluctant to admit new production integrations, and it has no official MCP server.

Dutch bookkeeping and invoicing software for small businesses and their accountants: sales invoices, customers, purchase invoices and receipts, bank, VAT returns and the ledger, in the browser as SnelStart Web.

## What is the SnelStart API?

Cotlet's SnelStart API exposes 14 endpoints for your own SnelStart account: list customers, search articles, list sales invoices, get a sales invoice, list purchases, list ledger accounts, create a customer, create a sales invoice concept, send or finish a sales invoice, create a credit invoice, send a payment reminder, register a payment, upload a purchase invoice or receipt and create a memorial entry. The list_customers endpoint returns lists customers (Relaties, Klanten) with name, VAT number and email address. Each endpoint takes simple JSON inputs like limit, invoice_id or query and works both as an operation of the snelstart_read or snelstart_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:** 2026-10-20

Yes, but it is gated (checked 14 Oct 2026). Cotlet is a hosted MCP server and REST API for SnelStart with 14 endpoints (6 read, 8 write): you sign in once in your own cloud browser, your AI agent does the work.

## Does SnelStart have an official API?

Yes, but it is gated (checked 14 Oct 2026). SnelStart has a B2B API for software partners: you request a connection, get a development key and portal access, and a production integration for several users needs certification, OAuth, a webhook URL and at least five named customers. SnelStart says it is reluctant to admit new production integrations, and it has no official MCP server.

| Task | SnelStart official | Cotlet |
|---|---|---|
| Create a customer | Partly: Endpoint list is visible only after B2B portal sign-up; a custom key covers one client | Yes |
| Create a sales invoice and save it as a concept | Partly: Same: documentation sits behind the portal | Yes |
| Email an invoice or send a reminder | Partly: Same: documentation sits behind the portal | Yes |
| Upload a purchase invoice or receipt | Partly: Same: documentation sits behind the portal | Yes |
| Register a payment or book a memorial entry | Partly: Same: documentation sits behind the portal | Yes |
| List open and overdue invoices | Partly: Same: documentation sits behind the portal | Yes |
| Use it from an AI agent for many companies without certification | No | Yes |

Sources: [SnelStart: API for developers (application, development key, certification)](https://www.snelstart.nl/api), [SnelStart B2B API developer portal](https://b2bapi-developer.snelstart.nl/), [SnelStart Web help: Functionaliteiten in SnelStart Web](https://kennispleinweb.snelstart.nl/nl/functionaliteiten-in-snelstart-web)

## For AI agents

```text
Yes, but it is gated (checked 14 Oct 2026). SnelStart has a B2B API for software partners: you request a connection, get a development key and portal access, and a production integration for several users needs certification, OAuth, a webhook URL and at least five named customers. SnelStart says it is reluctant to admit new production integrations, and it has no official MCP server.
Cotlet provides a hosted MCP server and REST API for SnelStart: 14 tools (6 read, 8 write).
Access       Sign up at https://cotlet.dev/app/signup?app=snelstart, then request the app and create API keys in the Cotlet console.

MCP server   https://cotlet.dev/mcp/v1
MCP tools    snelstart_read, snelstart_write, reads and writes apart; call one with {"operation": "<operation>", "arguments": {...}}
REST base    https://cotlet.dev/api/v1/snelstart, each operation at its own route, e.g. POST /api/v1/snelstart/customers/{customer_id}/sales-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_customers, search_articles, list_sales_invoices, get_sales_invoice, list_purchases, list_ledger_accounts, create_customer, create_sales_invoice, issue_sales_invoice, create_credit_invoice, send_invoice_reminder, register_payment, upload_purchase_document, create_memorial_entry
Confirm      issue_sales_invoice, create_credit_invoice, send_invoice_reminder, register_payment, create_memorial_entry (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/snelstart-api-mcp-server.md

How access works:
1. The user signs up at https://cotlet.dev/app/signup?app=snelstart, requests SnelStart in the Cotlet console and creates an API key there.
2. The user signs in to SnelStart once in their Cotlet Cloud Browser (their own Chrome in the cloud, opened from the console) and enables SnelStart 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 SnelStart 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 SnelStart 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 SnelStart 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 SnelStart 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 SnelStart 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 SnelStart's terms; Cotlet is not affiliated with SnelStart.
```

## What can an AI agent do in SnelStart?

Cotlet is best for Dutch small businesses and bookkeepers who send invoices, chase late payers and process supplier invoices in SnelStart Web without running or fixing a server.

- **[Create and send sales invoices](https://cotlet.dev/integrations/snelstart-api-mcp-server/create-and-send-sales-invoices.md)** (runs: weekly): "For each customer in this list, create a sales invoice in SnelStart with the hours and article I give you. Show me each concept first, then send it by email after I say OK." → `list_customers`, `search_articles`, `create_sales_invoice`, `issue_sales_invoice`
- **[Send payment reminders for overdue invoices](https://cotlet.dev/integrations/snelstart-api-mcp-server/send-payment-reminders.md)** (runs: weekly): "List my overdue sales invoices in SnelStart and show me who is late and by how many days. After I say OK, send the standard reminder for each one." → `list_sales_invoices`, `get_sales_invoice`, `send_invoice_reminder`
- **[Upload purchase invoices and receipts](https://cotlet.dev/integrations/snelstart-api-mcp-server/upload-purchase-invoices.md)** (runs: daily): "Upload the supplier invoices and receipts from this folder to SnelStart, then list everything that is still Te controleren and tell me which ledger account each one is on." → `upload_purchase_document`, `list_purchases`, `list_ledger_accounts`
- **Register customer payments on invoices** (runs: weekly): "List my open sales invoices in SnelStart. For the ones I tell you were paid in cash on a given date, register the payment in the cash journal." → `list_sales_invoices`, `register_payment`
- **Book month-end memorial entries**: "Book this correction as a memorial entry in SnelStart: debit ledger account 4000 and credit 1800 for 1,200.00, dated the last day of the month, with this description. Show me the entry first." → `list_ledger_accounts`, `create_memorial_entry`

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

Yes. Cotlet does not replace your automation platform: it gives it a SnelStart 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 create and send sales 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/snelstart/customers. | 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/snelstart/customers 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 SnelStart.

### list_customers

Lists customers (Relaties, Klanten) with name, VAT number and email address. Access: read. REST: `GET /api/v1/snelstart/customers`. MCP: `snelstart_read → list_customers`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `query` | string | no | Part of the customer name. |
| `limit` | integer | no | Records per page. Default: 50. |
| `cursor` | string | no | Next page cursor from the previous call. |

Returns customers from Relaties, Klanten in the order SnelStart shows them, with the VAT number and the email address on the card. The email address matters because SnelStart Web mails invoices only to a filled-in address.

Example response:

```json
{
  "customers": [
    {
      "customer_id": "cus_8f21",
      "name": "Northwind Studio",
      "vat_number": "NL123456789B01",
      "email": "billing@northwind.example"
    }
  ],
  "next_cursor": null
}
```

### search_articles

Finds articles by name so an invoice line can use them. Access: read. REST: `GET /api/v1/snelstart/articles/search`. MCP: `snelstart_read → search_articles`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `query` | string | yes | Part of the article name. |
| `limit` | integer | no | Records per page. Default: 50. |

Returns matching articles with ID, name and price. SnelStart needs an article on every invoice line, even for hours or services, and each article belongs to a revenue group, which cannot be created in SnelStart Web.

Example response:

```json
{
  "articles": [
    {
      "article_id": "art_104",
      "name": "Consulting hour",
      "unit_price": 95
    }
  ]
}
```

### list_sales_invoices

Lists sales invoices from the invoice overview, filtered by status. Access: read. REST: `GET /api/v1/snelstart/sales-invoices`. MCP: `snelstart_read → list_sales_invoices`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `status` | string | no | One of: all, concept, overdue, open, paid. Default: all. |
| `customer_id` | string | no | Only invoices of this customer, from list_customers. |
| `limit` | integer | no | Records per page. Default: 50. |
| `cursor` | string | no | Next page cursor from the previous call. |

Returns invoices with number, customer, amount, due date and status, mirroring the overview filters alles, concept, vervallen, openstaand and betaald. A concept has no invoice number yet. Open invoices are the ones still unpaid.

Example response:

```json
{
  "invoices": [
    {
      "invoice_id": "inv_2026_0388",
      "number": "2026-0388",
      "customer": "Bakker Logistics",
      "amount_total": 919.6,
      "due_date": "2026-09-26",
      "status": "overdue"
    }
  ],
  "next_cursor": null
}
```

### get_sales_invoice

Returns one sales invoice with its lines, VAT mode and customer email. Access: read. REST: `GET /api/v1/snelstart/invoices/{invoice_id}/sales-invoice`. MCP: `snelstart_read → get_sales_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `invoice_id` | string | yes | Sales invoice ID from list_sales_invoices or create_sales_invoice. |

Returns header, lines, totals, the customer email address and whether the invoice is a regular invoice or an e-invoice. The PDF is the same file the download icon in the overview gives.

Example response:

```json
{
  "invoice_id": "inv_2026_0388",
  "number": "2026-0388",
  "customer": "Bakker Logistics",
  "customer_email": "ap@bakker.example",
  "vat_mode": "exclusive",
  "lines": [
    {
      "description": "Consulting hour",
      "quantity": 8,
      "unit_price": 95
    }
  ],
  "amount_excl": 760,
  "amount_total": 919.6,
  "is_e_invoice": false,
  "status": "overdue"
}
```

### list_purchases

Lists purchase invoices and receipts from Inkopen, optionally only unprocessed ones. Access: read. REST: `GET /api/v1/snelstart/purchases`. MCP: `snelstart_read → list_purchases`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `only_unprocessed` | boolean | no | Only purchases with status Te controleren. Default: false. |
| `status` | string | no | One of: all, overdue, open, paid. Default: all. |
| `limit` | integer | no | Records per page. Default: 50. |
| `cursor` | string | no | Next page cursor from the previous call. |

Returns each purchase with supplier, date, amount, status and the ledger account it sits on. A purchase on the temporary account Vraagposten stays Te controleren until someone picks a cost account.

Example response:

```json
{
  "purchases": [
    {
      "purchase_id": "pur_551",
      "supplier": "Hosting BV",
      "date": "2026-10-12",
      "amount_total": 48.4,
      "ledger_account": "Vraagposten",
      "status": "to_check"
    }
  ],
  "next_cursor": null
}
```

### list_ledger_accounts

Lists ledger accounts (grootboekrekeningen) with code and name. Access: read. REST: `GET /api/v1/snelstart/ledger-accounts`. MCP: `snelstart_read → list_ledger_accounts`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `query` | string | no | Part of the account name or code. |
| `limit` | integer | no | Records per page. Default: 50. |

Returns code and name for each ledger account, so a booking or an upload review can name a real account. Ledger accounts are available from the inKaart package in SnelStart Web.

Example response:

```json
{
  "accounts": [
    {
      "code": "4000",
      "name": "Kantoorkosten"
    },
    {
      "code": "1800",
      "name": "Vooruitbetaalde kosten"
    }
  ]
}
```

### create_customer

Adds a customer under Relaties, Klanten. Access: write. REST: `POST /api/v1/snelstart/customers`. MCP: `snelstart_write → create_customer`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `name` | string | yes | Customer name, at least 4 characters. |
| `email` | string | no | Email address for invoices. |
| `vat_number` | string | no | VAT number, entered under company details. |

Creates the customer card and returns its ID. SnelStart refuses names shorter than four characters, and Web cannot import customers or store price agreements. It sends nothing and reaches no one, so it does not ask for confirmation.

Example response:

```json
{
  "customer_id": "cus_9a03",
  "name": "Bakker Logistics",
  "email": "ap@bakker.example",
  "vat_number": "NL987654321B01"
}
```

### create_sales_invoice

Saves a sales invoice as a concept, without sending it. Access: write. REST: `POST /api/v1/snelstart/customers/{customer_id}/sales-invoices`. MCP: `snelstart_write → create_sales_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `customer_id` | string | yes | Customer ID from list_customers. |
| `lines` | array | yes | Lines of {article_id, quantity, description (optional)}. Article IDs come from search_articles. |
| `vat_mode` | string | no | One of: inclusive, exclusive, reverse_charged. Default: exclusive. |
| `discount_percent` | number | no | Discount on the whole invoice, in percent. |
| `order_reference` | string | no | Optional order reference. |

Does what "Tussentijds opslaan" does: it keeps a concept in the invoice overview. A concept has no invoice number and nobody receives it, so it does not ask for confirmation. Discounts apply to the whole invoice. The response shows the totals SnelStart calculated.

Example response:

```json
{
  "invoice_id": "inv_c_0041",
  "number": null,
  "status": "concept",
  "customer": "Northwind Studio",
  "vat_mode": "exclusive",
  "lines": [
    {
      "description": "Consulting hour",
      "quantity": 12,
      "unit_price": 95
    }
  ],
  "amount_excl": 1140,
  "vat": 239.4,
  "amount_total": 1379.4
}
```

### issue_sales_invoice

Emails a concept invoice to the customer or saves it without sending. Access: write, asks the user first. REST: `POST /api/v1/snelstart/invoices/{invoice_id}/sales-invoices`. MCP: `snelstart_write → issue_sales_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `invoice_id` | string | yes | Sales invoice ID from list_sales_invoices or create_sales_invoice. |
| `action` | string | yes | One of: send, save_only. send emails the invoice, save_only finishes it without email. |
| `email_text` | string | no | Replaces the default email text for this invoice. |

Does what Versturen or Alleen Opslaan does in step 4. SnelStart assigns the invoice number at that moment, so the invoice stops being a concept. Sending needs the customer email address on the card and attaches a UBL file. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "invoice_id": "inv_c_0041",
  "number": "2026-0412",
  "status": "open",
  "sent_to": "billing@northwind.example",
  "amount_total": 1379.4
}
```

### create_credit_invoice

Credits a sales invoice in full or in part, as Crediteren does. Access: write, asks the user first. REST: `POST /api/v1/snelstart/invoices/{invoice_id}/credit-invoices`. MCP: `snelstart_write → create_credit_invoice`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `invoice_id` | string | yes | Sales invoice ID from list_sales_invoices or create_sales_invoice. |
| `lines` | array | no | Lines of {article_id, quantity} to credit. Omit to credit the whole invoice. |
| `action` | string | no | One of: send, save_only. Default: save_only. |

Copies the invoice into a new one with negative amounts, optionally with fewer lines or quantities. Both invoices stay in the overview. Creating a credit invoice needs inStap, and writing off the original in the memorial journal needs inKaart. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "credit_invoice_id": "inv_cr_0007",
  "number": "2026-0414",
  "credits": "2026-0388",
  "amount_total": -919.6,
  "status": "saved"
}
```

### send_invoice_reminder

Emails the customer that an invoice is still open and attaches the invoice again. Access: write, asks the user first. REST: `POST /api/v1/snelstart/invoices/{invoice_id}/reminder`. MCP: `snelstart_write → send_invoice_reminder`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `invoice_id` | string | yes | Sales invoice ID from list_sales_invoices or create_sales_invoice. |

Does what the Herinnering button on an open invoice does, from the inStap package. It works for a regular invoice only, not for an e-invoice, and the call returns an error for an invoice that is already paid. The customer receives the email. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "invoice_id": "inv_2026_0388",
  "number": "2026-0388",
  "reminder_sent_to": "ap@bakker.example",
  "sent_at": "2026-10-14T09:12:00+02:00"
}
```

### register_payment

Registers a purchase or sales invoice as paid in a bank or cash journal. Access: write, asks the user first. REST: `POST /api/v1/snelstart/invoices/{invoice_id}/payments`. MCP: `snelstart_write → register_payment`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `invoice_id` | string | yes | Sales invoice ID from list_sales_invoices or create_sales_invoice. |
| `journal` | string | yes | Bank or cash journal that is not linked to a bank account number. |
| `date` | string | no | Payment date, YYYY-MM-DD. Default: today. |
| `amount` | number | no | Amount paid. Default: the open amount. |

Does what Betaling registreren does on an invoice line. SnelStart documents it only for administrations without a bank connection or manual bank statement import; otherwise the payment must be linked to the bank transaction instead. The call changes the books. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "invoice_id": "inv_2026_0391",
  "number": "2026-0391",
  "journal": "Kas",
  "paid_on": "2026-10-13",
  "amount": 575,
  "status": "paid"
}
```

### upload_purchase_document

Uploads one PDF, UBL, PNG or JPG file to Inkopen for SnelStart to read. Access: write. REST: `POST /api/v1/snelstart/purchase-documents`. MCP: `snelstart_write → upload_purchase_document`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `file_name` | string | yes | File name with extension: pdf, xml (UBL), png, jpg or jpeg. |
| `file_base64` | string | yes | File contents, base64 encoded. |

Does what dragging a file into Inkopen does. SnelStart reads the file and lists it as a purchase with status Te controleren, with the date, amount and supplier it recognised. Recognition is not 100 percent accurate, and the purchase stays on Vraagposten until a cost account is set. The upload reaches no one and books nothing final, so it does not ask for confirmation.

Example response:

```json
{
  "purchase_id": "pur_552",
  "status": "to_check",
  "recognised": {
    "supplier": "Hosting BV",
    "date": "2026-10-12",
    "amount_total": 48.4
  },
  "ledger_account": "Vraagposten"
}
```

### create_memorial_entry

Books a memorial entry (memoriaalboeking) with debit and credit lines. Access: write, asks the user first. REST: `POST /api/v1/snelstart/memorial-entries`. MCP: `snelstart_write → create_memorial_entry`.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `date` | string | yes | Entry date, YYYY-MM-DD. |
| `description` | string | yes | Entry description. |
| `lines` | array | yes | Lines of {ledger_account, debit or credit, amount}. Debits and credits must be equal. |

Does what a new entry under Financieel, Beginbalans en Memoriaal, Tussenrekening Memoriaal does. It needs the inKaart package. The call refuses lines that do not balance and returns the entry with its lines. It changes the ledger. By default you confirm each call; you can switch that off for this tool.

Example response:

```json
{
  "entry_id": "mem_204",
  "date": "2026-10-31",
  "description": "Accrual October",
  "lines": [
    {
      "ledger_account": "4000",
      "debit": 1200
    },
    {
      "ledger_account": "1800",
      "credit": 1200
    }
  ]
}
```

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

Connecting SnelStart takes three steps: sign up, sign in to SnelStart 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 SnelStart to your agent.

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

2. **Sign in to SnelStart in your Cloud Browser** Open your Cloud Browser in the console: your own Chrome in the cloud. Sign in to SnelStart 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 SnelStart 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.

```
For each customer in this list, create a sales invoice in SnelStart with the hours and article I give you. Show me each concept first, then send it by email after I say OK.
```

### Call SnelStart 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/snelstart 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/snelstart/customers/cus_8f21/sales-invoices \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"vat_mode":"exclusive","lines":[{"article_id":"art_104","quantity":12}]}'
```

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

```
{
  "invoice_id": "inv_c_0041",
  "number": null,
  "status": "concept",
  "customer": "Northwind Studio",
  "vat_mode": "exclusive",
  "lines": [
    {
      "description": "Consulting hour",
      "quantity": 12,
      "unit_price": 95
    }
  ],
  "amount_excl": 1140,
  "vat": 239.4,
  "amount_total": 1379.4
}
```

## Why use Cotlet for SnelStart?

**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 SnelStart 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 SnelStart changes, the tool pauses until we fix it.
- Failed calls cost nothing.

## Is it safe to connect SnelStart to Cotlet?

Yes. You sign in to SnelStart yourself, in your own Cloud Browser, and we never save your password. Your agents only get SnelStart 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 SnelStart integration?**

No, Cotlet is independent of SnelStart. SnelStart's own API is open only to approved partners. Cotlet works through your own SnelStart account, the way you use SnelStart 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 SnelStart in your console: your agents lose access at once and you stay signed in. Signing out of SnelStart in the browser works too, and Reset browser deletes the whole profile.

## Is there a SnelStart MCP server on GitHub?

Yes. Community SnelStart MCP servers exist on GitHub, usually maintained by one person. You install one yourself, use your own API key from the SnelStart developer program, and fix it when something changes. SnelStart also has an official API, but a production key needs certification and five named customers. Cotlet hosts the same kind of server for you and our team keeps it working.

|  | GitHub MCP server | Cotlet |
|---|---|---|
| Setup | Request a SnelStart developer connection, get a key, install and configure the server | Sign up, sign in to SnelStart Web once, add one MCP server or API key |
| When SnelStart changes | It breaks until the maintainer or you fix it | Our team tests it daily and fixes it for you; failed calls are free |
| Your session | You hold a developer or customer key and keep it safe | Signed in inside your own Cloud Browser in the EU, profile encrypted, only for the apps you enable, disabled for agents in one click |
| Production use | A key for one client works; offering it to many users needs SnelStart certification | No certification step for you; you use your own account |
| Upkeep | You host, monitor and update it | Nothing to host or update |
| Where it runs | On your own machine or server | Hosted: Claude Code, Codex, Cursor, n8n and scripts, also on a schedule |
| Price | Free software; your time and hosting are the cost | 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 SnelStart 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 SnelStart API cost?

Free 7-day trial with 2,000 credits, no card needed. After that, the SnelStart 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 SnelStart 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 SnelStart 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 SnelStart only after you enable it. When SnelStart 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 SnelStart, sign out of SnelStart 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.
- **SnelStart's terms:** You use your own SnelStart account and stay responsible for following SnelStart's terms. Cotlet is independent and not affiliated with SnelStart. [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 SnelStart in the console and press Request access. Then you create your API key and connect SnelStart there.

**Do I need to be technical?**

No. You sign in to SnelStart 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 SnelStart to Cotlet?**

Yes. You sign in to SnelStart yourself, in your own Cloud Browser in the EU, and we never save your password. Your agents only get SnelStart 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 SnelStart 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 SnelStart 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 SnelStart's pages. It sends the same requests your browser would, from your browser's IP with its cookies, without opening a window. SnelStart 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 SnelStart 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?**

SnelStart 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).

**Which SnelStart package do I need?**

It depends on the tool. SnelStart lists customers and sales invoices, credit invoices and reminders from inStap, and ledger accounts, memorial entries and payment links from inKaart (checked 14 Oct 2026). The tool returns an error when your package lacks the feature.

**Does this work with SnelStart 12 or only SnelStart Web?**

The tools follow SnelStart Web (web.snelstart.nl). Some features, such as creating revenue groups, combined invoices and price agreements, exist only in SnelStart 12 and are not covered.

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

No. Every call to issue_sales_invoice, create_credit_invoice, send_invoice_reminder, register_payment or create_memorial_entry 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_customer, create_sales_invoice, upload_purchase_document runs without asking, because it sends nothing to anyone and one call undoes it.

**Can I use the SnelStart 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/snelstart 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.