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Checkly vs Testfully

Checkly scores higher on the AgentReady, 85/100 against 49/100. They differ on 16 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Checkly. The active reliability layer for developers & agents.

Testfully. A single product to build, test, document and monitor APIs.

Where Checkly is ahead

Checkly passes openapi / spec quality, authentication documented, request examples provided, response examples provided, errors and status codes documented and limits / constraints documented, and Testfully does not. That is understand, whether an agent can read the docs and work out how the API behaves before calling it.

It also holds adopt: programmatic credential creation, fast time to first request and copyable quickstart. Testfully misses those.

And on operate, structured, predictable output, machine-readable errors, retry behavior documented, rate-limit behavior predictable, observable execution and agent compatibility verified. Testfully misses those.

Where Testfully is ahead

Testfully passes llms-full.txt / full agent docs, and Checkly does not. That is discover, whether an agent can find the product at all without being told it exists.

What neither does

Both fail mcp discoverable, no mandatory sales call, official python sdk, mcp integration available, idempotency support. If your agent needs any of those, you will be building it yourself either way.

Score, pillar by pillar

The AgentReady splits into four pillars, scored separately, because a product can be easy to find and still impossible to adopt.

Discover. Testfully leads 87 to 80. Checkly misses llms-full.txt / full agent docs, mcp discoverable; Testfully misses mcp discoverable.

Understand. Checkly leads 100 to 38. Checkly misses nothing; Testfully misses openapi / spec quality, authentication documented, request examples provided, response examples provided, errors and status codes documented, limits / constraints documented.

Adopt. Checkly leads 65 to 48. Checkly misses no mandatory sales call, official python sdk, mcp integration available; Testfully misses no mandatory sales call, programmatic credential creation, fast time to first request, copyable quickstart, official python sdk, mcp integration available.

Operate is whether an agent can run against it in production and recover when a call fails. Checkly leads 94 to 24. Checkly misses idempotency support; Testfully misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, observable execution, agent compatibility verified.

Pricing

Checkly does not publish a machine-readable starting price and has a free tier. Testfully does not publish one and has a free tier.

Signal by signal

Which to pick

Checkly clears more of the signals an agent needs, so it is the safer default for unattended use. Full profiles: Checkly and Testfully. Alternatives to each: Checkly, Testfully.

An agent can fetch this as data: POST /v1/compare {"slugs": ["checklyhq", "testfully"]}