Which AI Agents Have a Public API? 72 of the 81 We Could Confirm

Of the 94 AI agents published in The Agents Index on 22 August 2026, we could determine public API availability for 81. Seventy-two of those 81 offer a public API and nine don’t. The other 13 listings are undetermined. We haven’t established an answer for them either way, and this census counts none of them as a No.

Every listing in our index carries a Public API field in its datasheet, beside Deployment and Open Source. It answers a question buyers usually ask late and should ask early: can I drive this thing from my own code, or only from the vendor’s screen?

The finding worth taking away

The 72 is the less interesting half. A public API is close to table stakes here, and a tool that has one isn’t telling you much by having it.

Here’s the half that’s worth something. Of the 35 tools you can run on your own infrastructure where we could determine the answer, 34 offer a public API. Of the 46 cloud-only tools we could determine, 38 do. Self-hostable tools are more likely to be callable, and the gap is wide enough to plan around.

Two forms of control that could vary independently mostly don’t. If a vendor lets you host the software, that same vendor almost always lets you call it. Eight of our nine confirmed negatives are cloud-only, so withholding the API and keeping the software on the vendor’s machines tend to travel together.

The exception, and why we’re printing it

When we last counted, on 19 August, this correlation had no exceptions at all: 34 of 34 self-hostable tools had an API, and all nine negatives were cloud-only. It has one exception now. Aider is a self-hostable, open-source, Apache-2.0 command-line coding assistant, and it has no public API.

The exception is real and it’s the right kind. Aider’s own scripting documentation offers two ways in, a command line and a Python class, and warns that the Python path “is not officially supported or documented, and could change in future releases without providing backwards compatibility.” There’s no HTTP endpoint to call. For a CLI you install and run yourself, that’s a coherent design choice and not a gap.

We’re saying this plainly because a census that only ever hardens its own findings isn’t measuring anything. The direction survived a corpus that grew from 81 listings to 94 since 13 August. The word “every” didn’t.

The nine with no public API

Nine tools in the index have no public API that we could find. What makes them worth a table isn’t the count but how much else they agree on.

Tool	Category	Deployment	Interface	Open source
Aider	Coding agents	Both	CLI	Yes
Bolt.new	Coding agents	Cloud	Web	No
Crescendo	Support agents	Cloud	Web	No
Decagon	Support agents	Cloud	Web	No
Gemini Code Assist	Coding agents	Cloud	IDE	No
Genspark	Research & data agents	Cloud	Web	No
Replit Agent	Coding agents	Cloud	IDE	No
Rox	Sales & marketing agents	Cloud	Web	No
Undermind	Research & data agents	Cloud	Web	No

Eight of these nine tools are cloud-only, and the same eight are closed-source. Six are web-first, two are IDE extensions, and one is the command-line exception. Aider sits apart on all three fields at once, which is a useful thing for the table to show: the absence of an API means something very different when you have the source.

This isn’t a criticism of any of the nine. Several are excellent at the job they do, and Decagon and Crescendo in particular are deliberately sales-led managed services where a self-serve API would be beside the point. It’s a description of what you’re buying. A tool in the closed-source eight is a destination, not a component. Whatever you build around it lives inside the vendor’s product and stops at its edges.

Where the APIs are, by category

Voice agents are the cleanest category in the index. All 11 voice agents in The Agents Index offer a public API, with no undetermined listings anywhere in the category. It’s the only category where we could answer the question for every member and the answer never varied, which makes sense. A voice agent your telephony stack can’t trigger and your CRM can’t reach isn’t much use, so the API is the product.

Category	Has a public API	None found	Determined	Undetermined
Coding agents	16	4	20 of 25	5
Agent platforms	12	0	12 of 15	3
Agent frameworks	11	0	11 of 14	3
Voice agents	11	0	11 of 11	0
Research & data agents	8	2	10 of 11	1
Support agents	6	2	8 of 9	1
Sales & marketing agents	7	1	8 of 8	0
Agent tools & infrastructure	2	0	2 of 2	0
Agencies & build partners	0	0	0 of 1	1

(Botsify and Sierra each belong to two categories and are counted once in each, so the members column sums to 96 against an index of 94 distinct tools. Only Botsify has a determined answer, so the Determined column sums to 82 against 81.)

Agent frameworks and agent platforms are unanimous where we have an answer, at 11 of 11 and 12 of 12. Nothing in either category was found lacking a public API.

Five of the nine negatives sit in research, support and sales and marketing, the categories bought by a function and not by a developer. Four sit in coding agents, which is also the largest category in the index. We wouldn’t push that further than we can support. Two of ten and two of eight are small numbers, and the honest claim is that these categories hold most of the confirmed negatives, not that a fixed share of them lacks an API.

What the undetermined 13 actually are

The 13 undetermined listings aren’t a random sample of the index, and part of the gap is the question fitting some products badly. Four are IDE extensions and three are code libraries, where “does it expose a REST API” is a different question from the one the field asks, because a library is itself the programmatic interface. The rest are three visual builders, two web tools, and one listing so new that no interface is recorded yet.

Six of those 13 are self-hostable: Juggler, Microsoft AutoGen, OpenAI Agents SDK, Pydantic AI, Windsurf and Zed. That’s why the self-host finding above is stated out of 35 and not out of 41. For any of the 13, the answer is to ask the vendor. We haven’t established one, and we’d rather say so than guess.

How to use this when you’re choosing

If you’re deciding between two tools that look alike on features, this field separates them faster than a demo will. Ask the two questions in this order: can I run it myself, and can I call it from my own code?

Because the two answers move together across most of our index, the first question is usually enough. A tool you can self-host is a tool you can integrate in 34 of the 35 cases where we know both. A No to both puts the tool in the closed-source eight above, and that’s a decision about how much of your workflow you’re willing to move inside someone else’s product.

Method

Counted on 22 August 2026 against all 94 listings published in The Agents Index on that date. The source is the Public API field on each listing’s datasheet, which records whether the vendor offers a conventional programmatic API a customer can call from their own code. An MCP server on its own doesn’t count as a public API under this definition. An API available only on an enterprise tier does.

What counts as determined. A tool is counted only where our research reached a conclusion we can point at: either positive evidence of a public API, or a documented negative finding naming the vendor pages and independent write-ups we checked.

Genspark is a representative negative. No public developer API appears across the vendor’s own pricing and feature pages or four independent feature write-ups, and genspark.ai returns HTTP 403 to automated fetches, so the finding is recorded as searched-and-not-found and not as a flat No.

What changed since the last count. On 19 August this page reported 72 of 81 as 71 of 80, against an index of 93. Three things moved and we can name all three. Agentix Labs was published on 19 August, taking the index to 94, with no API answer recorded yet. Aider moved from undetermined to No on 20 August when a research pass established it. Unify moved from No to Yes on 19 August: its llms.txt documents a Data API, a Sequences API, an Analytics API and a Bulk API, which an earlier read of its integrations pages had missed. So the determined count rose by one, the Yes count rose by one, and the negatives held at nine with Unify out and Aider in.

An absence is not a zero. No undetermined tool is counted as lacking a public API anywhere on this page. Every ratio above is stated out of the tools where we reached an answer, and the denominator is written into the sentence.

Counts are a snapshot of a moving index and will drift as tools are added and vendors ship. If you want to cite a figure from this page, cite it with its date: The Agents Index, 22 August 2026. Our full research process is described in how we research AI agents.