Mollie API: connect Mollie to your accounting and webshop

What you can do with the Mollie API

• Match payments to the right invoice in your accounting
• Refunds as a credit note or reversing entry
• Split settlements into orders and fees
• Write the payment status back to your webshop or CRM
• Keep track of recurring payments and subscriptions

How the integration works

A Mollie webhook only reports that something has changed, with the ID of the payment. The integration then fetches the current status from Mollie itself and processes it. That way it also works when a notification arrives twice or in a different order.

Facts about the Mollie API

Checked on 2 November 2026 against the official documentation. Limits, prices and versions change; the source is listed per row.

Fact	What the documentation says	Source
Authentication	API keys per website profile (test and live) or OAuth through Mollie Connect for third-party integrations. A key is shown once.	Mollie: Authentication
Token lifetime	OAuth access token 1 hour; the refresh token does not expire. API keys do not expire.	Mollie: Generate tokens
Rate limits	Per merchant, separately for reads and writes, calculated dynamically and visible in the RateLimit headers. When exceeded, 429 with Retry-After. Test mode may have lower limits.	Mollie: Rate limiting
Webhooks	The classic webhook only sends an id; you fetch the status yourself. Ten attempts spread over 26 hours. The new webhooks (beta) send events such as payment.paid with an X-Mollie-Signature.	Mollie: Webhooks
Test environment	Test mode with a test API key, euros only, fully separated from live; webhooks also fire in test mode.	Mollie: Testing
Version	API v2. The v1 API was shut down on 31 December 2024; the Orders API is no longer recommended, use the Payments API.	Mollie: Migrating v1 to v2
Duplicate requests	An Idempotency-Key header on POST prevents duplicate payments or refunds; Mollie keeps it for an hour.	Mollie: Idempotency
API cost	No separate API cost; you pay per successful transaction.	Mollie: Pricing
n8n	No built-in node; there are community nodes on npm, including a package from Mollie itself (January 2026). I connect through the API with an HTTP step.	n8n documentation

What you need on your side

• A Mollie administrator who can create a test key and a live key per website profile
• Access to the accounting package where payments, refunds and payouts should land
• A fixed reference per order that exists both in Mollie and in the accounts
• Agreements with your accountant on how payouts and fees are booked

Where it often goes wrong, and how I prevent it

• The webhook is not proof: the integration only trusts the status it fetches from Mollie itself.
• Bundled settlements: one settlement contains many payments minus fees. They have to be split out to reconcile with the bank.
• Refunds and chargebacks: these need their own entry, not a correction on the original invoice.
• Test and live: Mollie has separate keys for test and live. The integration runs in test first.

In practice

In webshop intakes this is a recurring problem: at the end of the month, going through the bank and splitting Mollie settlements into orders by hand. That is exactly the work this integration takes over.

What it costs

I build a Mollie integration as one scoped process for a fixed price, from €750. Maintenance and monitoring are a monthly fee: n8n management from €250 per month, server management €145 per server. In the free assessment we work out your process. All prices and what is included →

What I do not do

• I do not build payment pages or a checkout; the integration processes what Mollie has already handled.
• I do not use the deprecated Orders API for new integrations.
• I never trust a status from a webhook; the integration always fetches the payment from Mollie itself.

Frequently asked questions about the Mollie API

Does n8n have a Mollie node?

No, not as an official built-in node. I connect Mollie through the API and webhooks in n8n.

Does the bank reconcile by itself afterwards?

The integration splits every settlement into payments and fees, so your accounting can match the bank line. Whatever does not match goes on a list.

Does this work with Moneybird, Exact and Zoho Books?

Yes. The Mollie side is always the same; only the accounting side differs per package.

Why does Mollie not include the status in the webhook?

Mollie's classic webhook only contains the id of the payment. That is deliberate: nobody can send a fake notification that way. The integration then fetches the current status from Mollie itself and processes it.

What happens if a Mollie webhook does not arrive?

Mollie tries ten times, spread over 26 hours. In addition the integration checks open payments at fixed intervals, so a missed notification is still processed.