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SnelStart API and MCP server

SnelStart's API is for certified software partners, and a production key needs OAuth, a webhook URL and five named customers. Sign in to SnelStart 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 SnelStart.

SnelStart has no API for this. So we run one for you.

SnelStart's own API, a GitHub MCP server and Cotlet compared
What you need SnelStart's APIGitHub MCP serverCotlet
Use for many companies without certification No Partly Yes, 14 tools
Acts as you, signed in 24/7 No No Yes, Cloud Browser
Fixed for you when SnelStart changes N/A No Yes, tested every 6h
Runs with your laptop off N/A No Yes, hosted

Checked Oct 14, 2026. Sources: SnelStart: API for developers (application, development key, certification) · SnelStart B2B API developer portal · SnelStart Web help: Functionaliteiten in SnelStart Web

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

  1. 01Sign in to SnelStart in your own Cloud Browser

  2. 02Connect it for your agents

  3. 03Cotlet keeps it signed in and working

How do I connect SnelStart 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. SnelStart 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/snelstart with its own method and path, such as POST /api/v1/snelstart/customers/{customer_id}/sales-invoices, with the same API key. Our open-source repo has ready scripts to start from.

REST API docs

What can the SnelStart API and MCP server do?

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

API reference
SnelStart tools in Cotlet's MCP server and REST API
Tool What it does Access
list_customers Lists customers (Relaties, Klanten) with name, VAT number and email address. read
search_articles Finds articles by name so an invoice line can use them. read
list_sales_invoices Lists sales invoices from the invoice overview, filtered by status. read
get_sales_invoice Returns one sales invoice with its lines, VAT mode and customer email. read
list_purchases Lists purchase invoices and receipts from Inkopen, optionally only unprocessed ones. read
list_ledger_accounts Lists ledger accounts (grootboekrekeningen) with code and name. read
create_customer Adds a customer under Relaties, Klanten. write
create_sales_invoice Saves a sales invoice as a concept, without sending it. write
issue_sales_invoice Emails a concept invoice to the customer or saves it without sending. writeasks first
create_credit_invoice Credits a sales invoice in full or in part, as Crediteren does. writeasks first
send_invoice_reminder Emails the customer that an invoice is still open and attaches the invoice again. writeasks first
register_payment Registers a purchase or sales invoice as paid in a bank or cash journal. writeasks first
upload_purchase_document Uploads one PDF, UBL, PNG or JPG file to Inkopen for SnelStart to read. write
create_memorial_entry Books a memorial entry (memoriaalboeking) with debit and credit lines. writeasks first

Scroll the table for all 14 tools.

Ask in plain words. Your agent does the rest.

All SnelStart use cases

Is it safe to connect SnelStart?

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 SnelStart 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 SnelStart 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 SnelStart have an 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.

How do I get access?

Sign up free, open SnelStart 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 SnelStart yourself and press Enable for agents. Your agent's calls go through it, from its IP with its cookies, so SnelStart 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: issue_sales_invoice, create_credit_invoice, send_invoice_reminder, register_payment, create_memorial_entry wait for your OK by default. You can switch that off per tool for scheduled runs.

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.

Should I use a SnelStart 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 SnelStart 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 SnelStart?

No. Cotlet is independent and not affiliated with SnelStart.

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