MCP or building on the Exact Online API yourself?

The Exact Online REST API is the layer everything runs on, Ledger Botje included. Building your own integration gives you complete freedom over what you build and how it behaves. An MCP server does not give you that freedom, but it does deliver the OAuth handling, rate-limit management, data cache and 292 ready-made actions an AI assistant can use straight away.

Short answer

Build it yourself when the integration is part of your own product or of a process nobody else runs quite that way. Use MCP when the goal is for an AI assistant to query and update your administration - otherwise you rebuild exactly the same layer.

The differences side by side

Ledger Botje (MCP) Your own REST API integration
Build time Connected in minutes Weeks to months, depending on scope
OAuth handling Included Build it yourself, token refresh included
Rate limits Managed, with cache and retry logic Monitor and handle it yourself
Available actions 292 fixed tools Everything the API exposes
Freedom Limited to the tools offered Complete
Usable by an AI assistant Directly, through the MCP protocol Only if you build that layer yourself
Maintenance on API changes Our problem Your problem
Cost From €39 per month Development time plus ongoing maintenance

Build on the API yourself when...

  • the integration is part of a product you ship to others.
  • you have a process so specific that no off-the-shelf tool covers it.
  • you need full control over timing, error handling and data storage.
  • you already have development capacity and can carry the maintenance.

Use MCP when...

  • the goal is for an AI assistant to query and update your administration.
  • you would rather not spend a development team on OAuth, tokens and rate limits.
  • you want to start quickly and decide later whether building your own is still needed.
  • you want the integration to keep pace with changes in the Exact Online API.

What you actually build when you build your own

The API call itself is the smallest part. Around it comes: the OAuth flow with PKCE, storing tokens securely and refreshing them in time, watching the daily call limit per administration, retrying after a 429, caching data you need often, and updating that cache when something changes in Exact Online.

That is precisely the layer an MCP server already has. If you are building purely to give an AI assistant access, you are rebuilding it.

Why an AI assistant cannot just use a REST API

An AI assistant needs more than endpoints: it needs a description of what each endpoint does, which parameters are meaningful, and when to use which. MCP standardises exactly that. Every tool arrives with a name, a description and a schema, so the model can choose without you writing an integration per assistant.

Build your own and you still write that description layer - and once per AI platform, because each platform has its own way of exposing tools.

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Does Ledger Botje use the same Exact Online API?

Yes. Ledger Botje talks to your administration through the regular Exact Online REST API, with the same OAuth authorisation you would use for your own integration. The difference is the layer on top.

Can I combine my own integration with Ledger Botje?

Yes. Both connect independently to the same administration through OAuth. Do keep an eye on the Exact Online daily call limit: it applies per administration and both integrations draw from it.

What happens when Exact Online changes its API?

With your own integration you absorb that change yourself. With Ledger Botje it is part of the maintenance; the MCP tools keep their names even when something shifts underneath.

Is MCP a replacement for the API?

No, MCP sits on top of it. The API remains the source; MCP is how an AI assistant can use that source in a structured way, without the model having to assemble HTTP requests itself.

Key facts

  • 292 MCP tools for Exact Online: 122 read-only and 170 write.
  • Works with 9 AI assistants: ChatGPT, Microsoft Copilot, Claude, Gemini, Mistral, Perplexity, Grok, Cursor and OpenClaw.
  • Connects via the Model Context Protocol (MCP) over Streamable HTTP, using OAuth 2.1 and PKCE.
  • From €39 per month. Every plan starts with a free 14-day trial, no credit card.

Tool counts verified on 25 July 2026.

Last updated: 25 July 2026