Authentication for just one FreeAgent Business Account

I’m new to FreeAgent and have been reviewing the API Docs.
I’m working on an integration using Integromat which is just from one CRM to FreeAgent.
On reviewing the authentication process, it seems that it is built for having many users wanting to access their FreeAgent account (so they are presented with the “allow access” page).

For me though, it is just one account that will always need access, and it is simply to create Invoices in FreeAgent (that have been created in the CRM first), so if I’ve understood the API docs correctly, the current setup would mean that I would see the “allow access” page each time I want to post a new Invoice (assuming it is more than 15mins between each invoice).

If I’ve misunderstood though, and you can point me in the right direction, that would be great.

Thanks in advance!

Hi Tom,

Thanks for posting your query and welcome to our API community! :wave: My name is Ewa and I’m one of the engineers looking after our API here at FreeAgent.

Normally, an individual user needs to go through the approval flow only once when beginning to use an integration. Once you’ve done that, FreeAgent will provide an authorization code which the integration should swap out for an access and refresh tokens. The access token is used to authorize subsequent API requests (e.g. to create new invoices); it is valid for one hour, but once it expires you can use your refresh token to obtain a new access token without having to go through the app approval process from scratch.

I’m not familiar exactly with how Integromat works, though I can see that they give you the ability to connect to any service that uses OAuth 2.0, which is exactly the process that I’ve just described.

I hope this helps!

Best wishes,


Hi Ewa,

That is great thank you for confirming and for the quick reply; much appreciated!

Have a good week!


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