# FreeAgent API — invoice reference and global sequencing

**URL:** <https://api-discuss.freeagent.com/t/freeagent-api-invoice-reference-and-global-sequencing/6559>\
**Category:** Uncategorized\
**Created:** [27 May 2026 11:48 UTC](https://api-discuss.freeagent.com/t/freeagent-api-invoice-reference-and-global-sequencing/6559 "2026-05-27T11:48:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![snappyfish](https://api-discuss.freeagent.com/user_avatar/api-discuss.freeagent.com/snappyfish/32/1227_2.png) [@snappyfish](https://api-discuss.freeagent.com/u/snappyfish)\
**Post date:** [27 May 2026 11:48 UTC](https://api-discuss.freeagent.com/t/freeagent-api-invoice-reference-and-global-sequencing/6559/1 "2026-05-27T11:48:11Z")

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I’m integrating with the FreeAgent API to create daily sales invoices via the Invoices endpoint. I have two questions:

How does the built-in Amazon integration create invoices with a reference like “Amazon Sales 2026-05-22” without it bumping the user’s global invoice sequence? Does the internal integration use a different mechanism than the public API?

When creating an invoice via the public API with a reference field set to a non-numeric string (e.g., “Sales 2026-05-27”), will FreeAgent’s global sequence counter attempt to increment from that value? Or does the counter only follow numeric/auto-sequenced references?

I’m trying to understand whether there’s a way to set a custom reference on an invoice via the API without disturbing the user’s own invoice numbering.

Thanks

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**Author:** ![joshpencheon](https://api-discuss.freeagent.com/user_avatar/api-discuss.freeagent.com/joshpencheon/32/1049_2.png) [@joshpencheon](https://api-discuss.freeagent.com/u/joshpencheon)\
**Post date:** [9 June 2026 13:03 UTC](https://api-discuss.freeagent.com/t/freeagent-api-invoice-reference-and-global-sequencing/6559/2 "2026-06-09T13:03:27Z")

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Hello,

FreeAgent’s built-in Amazon integration makes use of contact-level sequencing for the contact(s) that it creates. You can read more about the different types of sequencing available in FreeAgent in [this knowledge base article](https://support.freeagent.com/hc/en-gb/articles/115001219130-How-invoice-numbering-works-in-FreeAgent).

When FreeAgent generates a reference for a new invoice, it will look for the latest existing invoice associated with the appropriate sequencing level (in order: recurring invoice profile, project, contact, global), and try and increment the reference from there:

```auto
INV123 -> INV124
Q1 INV123 -> Q1 INV124
MYREF -> MYREF001

```

So while it isn’t possible to prevent an invoice’s reference influencing future reference generation entirely, the use of a contact with contact-level sequencing or a project with project-level sequencing can contain the influence to just those levels’ invoices.

Kind regards,  
Josh  
FreeAgent engineering