Finance & ERP · Integration
FreeAgent
Add FreeAgent to your product for your customers, and give your AI agents governed access to it.
FreeAgent is accounting built for small businesses and contractors, so the object model is smaller and more opinionated than a general ledger, which actually makes it easier to integrate correctly. Invoices, contacts, expenses and bank transactions are the core, and the reconciliation between an invoice and the bank transaction that paid it is where the real work sits. Everything is scoped to one company, so the account is the tenancy boundary and there is no cross-company query to get wrong. Accounting data is audited by someone eventually, so writes need to be idempotent rather than merely retried. fastn handles the OAuth per customer and keeps token refresh out of your product.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let a customer connect their own FreeAgent account so invoicing and expenses appear inside your product.
Raise an invoice from your product against the customer's own contacts and their numbering.
Read bank transactions to show what has actually been paid rather than what was billed.
React when an invoice is paid, rather than reconciling on a schedule.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent reports which invoices are overdue and which have a matching bank transaction.
An agent drafts an invoice within governed permissions, with the write audited per tenant.
An agent explains the gap between billed and received for a period.
Example prompt
Which invoices are overdue, and has any payment come in that has not been reconciled?
Set up FreeAgent in 4 steps
- 01Enable the FreeAgent connector from your fastn dashboard.
- 02Have each customer authorise their own FreeAgent account, so calls run under their credentials rather than a shared key.
- 03Decide which invoices, payments and vendors your product needs, map those fields, then enable the actions and triggers you want.
- 04Call it from your product and expose it to your agents through the same governed connection.
Why teams use the FreeAgent integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a FreeAgent integration without building it. Your customers connect their own FreeAgent account inside your product and work their invoices, payments and vendors there, with no per-customer code on your side.
- Handle the part that actually costs time: financial writes must be idempotent and reconcilable, because a duplicate is an accounting problem rather than a bug. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a FreeAgent update is not your on-call problem.
- One integration serves your product and your agents. The same governed FreeAgent connection powers in-product features and gives AI agents scoped, audited access, so you move financial records without hand-keying them between systems without wiring it twice.
Used by these teams
Compare with
Xero
QuickBooks
Zoho BooksOften used alongside
Tools the same teams tend to run next to FreeAgent, across other categories.
Shopify
Stripe
BigCommerce
AfterShipFreeAgent integration FAQ
How do I add a FreeAgent integration to my product?
Enable the FreeAgent connector in your fastn dashboard, then let each customer authenticate their own FreeAgent account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no FreeAgent client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own FreeAgent account?
Yes. Every connection is scoped to the individual customer, so each authorises their own FreeAgent account and only ever sees their own invoices, payments and vendors. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this FreeAgent integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent reports which invoices are overdue and which have a matching bank transaction.
Who maintains the FreeAgent integration?
fastn does. When FreeAgent changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Is the FreeAgent integration safe for financial writes?
Writes are idempotent, so a retry after a timeout does not post a document twice, and every call is logged per tenant so an entry can be traced back to the event that created it. That matters more in finance than anywhere else, because a duplicate is a number somebody has to explain.
Can it handle each customer's own chart of accounts?
Yes. ERP deployments are configured to the business, so account structures, required fields and fiscal calendars differ per customer. Those are mapped per tenant as configuration, not hard-coded.
What about FreeAgent rate limits during a first import?
Backfills are throttled deliberately. ERP limits are often account-wide rather than per-integration, so an unthrottled import can exhaust a customer's allowance and disrupt their other integrations.
What can I build with the FreeAgent integration?
A common starting point: let a customer connect their own FreeAgent account so invoicing and expenses appear inside your product. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the FreeAgent integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding FreeAgent does not change your per-connector cost. You can start free with 3 connected accounts.
Add FreeAgent to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.