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Fiken API and MCP server

Fiken's API is a paid add-on and has no endpoint for payment reminders or dunning letters. Sign in to Fiken 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 Fiken.

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

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

Checked Oct 14, 2026. Sources: Fiken API v2 documentation · Fiken Help: Hvordan bruke Fikens API · Fiken Help: Hvordan lage faktura i Fiken · Fiken Help: Registrere kjøp og utgifter

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

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

  2. 02Connect it for your agents

  3. 03Cotlet keeps it signed in and working

How do I connect Fiken 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. Fiken 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/fiken with its own method and path, such as POST /api/v1/fiken/invoices, with the same API key. Our open-source repo has ready scripts to start from.

REST API docs

What can the Fiken API and MCP server do?

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

API reference
Fiken tools in Cotlet's MCP server and REST API
Tool What it does Access
list_contacts Customers and suppliers with ID, name, organisation number, email and customer or supplier number. read
list_invoices Sales invoices with number, customer, dates, gross amount and remaining balance. read
get_invoice One invoice with its lines, totals, sent state and payments. read
list_purchases Purchases with supplier, date, invoice number, gross amount and what is still unpaid. read
list_inbox Documents in the Fiken inbox with name, upload date and whether they are used. read
list_bank_accounts Bank accounts registered in the company, with the account code payments are booked on. read
create_contact Add a customer or supplier with name, email and organisation number. write
create_invoice_draft Save an invoice draft for a customer. Nothing is booked and nothing is sent. write
create_invoice Issue an invoice and book the income. It is created, not sent. writeasks first
send_invoice Send an invoice to the customer by EHF, eFaktura, email, SMS or letter. writeasks first
register_invoice_payment Register a received payment, full or partial, on a customer invoice. writeasks first
create_reminder Send a payment reminder or a dunning letter for an overdue invoice. writeasks first
upload_receipt Put a receipt or supplier invoice in the Fiken inbox so it can be attached to a purchase. write
create_purchase Register a purchase from a supplier or a cash purchase, with VAT, cost account and payment. writeasks first

Scroll the table for all 14 tools.

Ask in plain words. Your agent does the rest.

All Fiken use cases

Is it safe to connect Fiken?

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 Fiken 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 Fiken 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 Fiken have an API?

Yes, Fiken has a documented REST API (v2) for invoices, sales, purchases, contacts, offers, credit notes and attachments (checked 14 Oct 2026), but it is a paid add-on: 99 NOK per month for a company registered in Brønnøysundregistrene. Apps that serve other companies must register an OAuth2 app, and Fiken publishes no MCP server of its own.

How do I get access?

Sign up free, open Fiken 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 Fiken yourself and press Enable for agents. Your agent's calls go through it, from its IP with its cookies, so Fiken 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: create_invoice, send_invoice, register_invoice_payment, create_reminder, create_purchase wait for your OK by default. You can switch that off per tool for scheduled runs.

Which Fiken access type does my user need?

Cotlet works with the access your own user has. Hele regnskapet can do everything in the books, including invoices and purchases. Se regnskapet uten å kunne gjøre endringer can only view, so only the list tools work for that user.

Can my agent delete or correct an invoice?

No. Fiken does not allow deleting an invoice, because the bookkeeping law requires a credit note instead, and Cotlet has no tool that creates credit notes. Create the credit note in Fiken with Opprett kreditnota for faktura.

Should I use a Fiken 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 Fiken 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 Fiken?

No. Cotlet is independent and not affiliated with Fiken.

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