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Pennylane API and MCP server

Pennylane's API is only on the Essentiel plan or higher, and it takes an admin-level token for each company to handle invoices, customers and transactions. Sign in to Pennylane 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 Pennylane.

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

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

Checked Oct 14, 2026. Sources: Pennylane API: Introduction · Pennylane API: Generating a Company API token · Pennylane API: Scopes · Pennylane MCP: Getting started

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

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

  2. 02Connect it for your agents

  3. 03Cotlet keeps it signed in and working

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

REST API docs

What can the Pennylane API and MCP server do?

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

API reference
Pennylane tools in Cotlet's MCP server and REST API
Tool What it does Access
list_customers Customers in your Pennylane account with name, type and email, optionally filtered by name. read
list_customer_invoices Customer invoices with number, customer, amounts, status and due date, newest first. read
get_customer_invoice One customer invoice with its lines, payments and matched bank transactions. read
list_supplier_invoices Supplier invoices with number, supplier, amounts and due date, newest first. read
list_suppliers Suppliers in your Pennylane account with name and ID, optionally filtered by name. read
list_transactions Bank transactions with date, label, amount, categories and matched invoices, newest first. read
list_categories Categories you use to analyse transactions and invoices, with their group and direction. read
create_customer Add a company or individual customer to your Pennylane customer list. writeasks first
create_customer_invoice Create an invoice for a customer, as a draft by default. writeasks first
finalize_customer_invoice Turn a draft invoice into a final one with an invoice number. writeasks first
send_customer_invoice Email a customer invoice to the customer or to the addresses you give. writeasks first
import_supplier_invoice Upload a supplier invoice PDF with its date, due date and amounts. writeasks first
categorise_transaction Set the categories of a bank transaction, with a weight for each. write
match_transaction Link a bank transaction to a customer invoice as its payment. writeasks first

Scroll the table for all 14 tools.

Ask in plain words. Your agent does the rest.

All Pennylane use cases

Is it safe to connect Pennylane?

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 Pennylane 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. Each call uses 10 credits, and your Cloud Browser uses 50 credits a day while Pennylane is enabled for agents, so 20 calls a day come to 250 credits.

See full pricing
Cotlet credit packs: price, credits and calls at 10 credits each
Credits Price, one time Calls at 10 credits Per 1,000 credits
5,000 $29 500 $5.80
15,000 $79 1,500 $5.27
32,000 $149 3,200 $4.66
60,000 $249 6,000 $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 Pennylane have an API?

Yes, Pennylane has a public REST API (Company API v2) with read and write scopes for customers, customer and supplier invoices, transactions, categories and ledger entries (checked 14 Oct 2026). It needs the Essentiel plan or higher and an API token, and the official Pennylane MCP server is read-only for now: it cannot create or send an invoice.

How do I get access?

Sign up free, open Pennylane 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 Pennylane yourself and press Enable for agents. Your agent's calls go through it, from its IP with its cookies, so Pennylane 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_customer, create_customer_invoice, finalize_customer_invoice, send_customer_invoice, import_supplier_invoice, match_transaction wait for your OK by default. You can switch that off per tool for scheduled runs.

Can the agent change an invoice after it is finalized?

No. Pennylane documents that a finalized invoice can no longer be edited, so create_customer_invoice makes a draft by default and finalize_customer_invoice asks for your OK.

Should I use a Pennylane 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 Pennylane 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 Pennylane?

No. Cotlet is independent and not affiliated with Pennylane.

Give your agent access to Pennylane.

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