CPA Field Guide / US tax & accounting
Independent · editorial · no pay-to-list

CPA & accounting software with an open API

How open a tool is to integration decides how much it locks you in. Here is every tool in this guide sorted by that — the ones with a self-serve public API first.

Open API — self-serve

You can generate an API key yourself and build against it, no approval needed.

Gated API

An API exists, but access needs approval, a partner program, or a higher plan.

Zapier only

No direct API; they connect to the rest of your stack through Zapier.

FAQ

Which CPA practice-management tool has the best API?

Karbon offers the most complete self-serve public API with webhooks; TaxDome also issues self-serve keys. Both let you build directly, without a partner agreement.

What does an open API mean for accounting software?

It means you can generate an API key yourself and integrate without vendor approval — the lowest-friction way to connect a tool to the rest of your firm's stack.

How this guide works

Most software directories rank by who pays. This one doesn't. It's a plain editorial reference, written to be useful to a working firm rather than to any vendor — including the one that maintains it.

No pay-to-list

No vendor pays for inclusion, placement, or ranking. There is no "sponsored" sort and no paid badges. Every product that meets a category's criteria can appear.

Only shipped capabilities

Each tool is described only by features it has actually released, sourced from the vendor's own product and developer documentation (reviewed July 2026). Roadmap items are not counted.

Categories a firm recognizes

Categories follow how US practices actually evaluate software, each with a stated definition and inclusion criteria. Deadline tracking is treated as a capability of practice management, with a small specialist list called out.

Who maintains it

CPA Field Guide is written and maintained by the team behind DueDateHQ, a deadline-monitoring tool listed in the guide. We describe every product — ours included — by the same standard, and never rank ours above its peers.

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