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Better Auth vs Kinde

Better Auth scores higher on the AgentReady, 57/100 against 54/100. They differ on 9 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Better Auth. A framework-agnostic, universal authentication and authorization framework for TypeScript.

Kinde. Modern auth and billing for engineers.

Where Better Auth is ahead

Better Auth passes structured api reference and limits / constraints documented, and Kinde 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: official typescript sdk, official python sdk and cli available. Kinde misses those.

Where Kinde is ahead

Kinde passes clear canonical domain and llms-full.txt / full agent docs, and Better Auth does not. That is discover, whether an agent can find the product at all without being told it exists.

It also holds adopt: no mandatory sales call. Better Auth misses it.

And on operate, observable execution. Better Auth misses it.

What neither does

Both fail openapi / spec quality, request examples provided, response examples provided, errors and status codes documented, agent-compatible signup flow, programmatic credential creation, fast time to first request, copyable quickstart, structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, agent compatibility verified. 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. Kinde leads 100 to 87. Better Auth misses clear canonical domain, llms-full.txt / full agent docs; Kinde misses nothing.

Understand is whether an agent can read the docs and work out how the API behaves before calling it. Better Auth leads 54 to 31. Better Auth misses openapi / spec quality, request examples provided, response examples provided, errors and status codes documented; Kinde misses structured api reference, openapi / spec quality, request examples provided, response examples provided, errors and status codes documented, limits / constraints documented.

Adopt. Better Auth leads 62 to 48. Better Auth misses no mandatory sales call, agent-compatible signup flow, programmatic credential creation, fast time to first request, copyable quickstart; Kinde misses agent-compatible signup flow, programmatic credential creation, fast time to first request, copyable quickstart, official typescript sdk, official python sdk, cli available.

Operate. Kinde leads 35 to 24. Better Auth misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, observable execution, agent compatibility verified; Kinde misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, agent compatibility verified.

Pricing

Better Auth starts at $0/month and has a free tier. Kinde starts at $25/mo and has a free tier.

Signal by signal

Which to pick

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

An agent can fetch this as data: POST /v1/compare {"slugs": ["better-auth", "kinde"]}