Connect Claude to Nordlet

This guide is for people who want Claude to work with their Nordlet books. Claude connects to the Nordlet MCP server at https://api.nordlet.com/mcp. You allow the connection once, on a Nordlet page. You do not copy any key.

1. Create a Nordlet account

1. Open app.nordlet.com and enter your e-mail address.
2. Accept the Terms of Service, the Privacy Policy and the Data Processing Agreement. Nordlet sends you a sign-in link. The link is valid for 15 minutes and works once. There is no password.
3. Open the link. Choose a plan: the flat rate, which starts with a free trial, or pay per request with a first top-up.
4. Create your company: name, country, registration code and VAT code. To try things first, tick Sandbox company. A sandbox holds test data and can be deleted at any time.

You can belong to several companies: your own, and companies whose owner invited you. Your role in each company (owner, admin, accountant, manager, developer or viewer) decides what you can do there. Claude gets the same rights.

2. Connect Claude

1. In Claude, add a custom connector with the address https://api.nordlet.com/mcp. Leave the authentication fields empty.
2. Claude opens a Nordlet page. If you are not signed in, Nordlet asks for your e-mail address and sends a sign-in link. Open the link in the same browser, and you come back to the page.
3. The page names the app that asks for access and the address you go back to. Check both, then choose Allow. Deny sends you back without access.
4. You are back in Claude, and the connector is connected.

Claude renews its access by itself. An access token is valid for one hour. Claude replaces it with a new one without asking you.

3. Connect Claude Code

Run:

claude mcp add --transport http nordlet https://api.nordlet.com/mcp

Then run /mcp in Claude Code and choose to authenticate the nordlet server. Your browser opens the same Nordlet page as in step 2. After Allow, the browser sends you back to Claude Code on your own computer.

4. Work in your companies

One connection works in every company you are a member of. Claude first lists your companies, then names the company in every call. Ask for the company by name, for example "issue this invoice in UAB Pavyzdys". When you are added to a new company, Claude can work in it at once. When you are removed from a company, Claude can no longer work in it.

Every call Claude makes is an ordinary API request and is counted like any other request. The changes it makes are recorded in the audit log.

5. Disconnect

1. In Nordlet, open Account → Developers. The connection is listed among your API keys under the app's name, for example "Claude".
2. Choose Revoke. Claude loses access at once, in every company.

To connect again, repeat step 2.

Using an API key instead

Owners, admins and developers can create an API key under Account → Developers and send it as a header. See MCP server.