Compare

Stream vs Vapi

Vapi scores higher on the AgentReady, 78/100 against 43/100. They differ on 21 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Stream. Stream provides APIs and SDKs for building in-app chat, activity feeds, video, audio, and moderation.

Vapi. Vapi is the developer platform for building voice AI agents.

Where Stream is ahead

Stream passes authentication documented, and Vapi 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: agent-compatible signup flow, official python sdk and cli available. Vapi misses those.

Where Vapi is ahead

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

It also holds understand: structured api reference, openapi / spec quality, pricing understandable, request examples provided, response examples provided and errors and status codes documented. Stream misses those.

And on adopt, self-service signup, programmatic credential creation, free trial or free allowance and fast time to first request. Stream misses those.

Finally, on operate, structured, predictable output, machine-readable errors, retry behavior documented, idempotency support and rate-limit behavior predictable. Stream misses those.

What neither does

Both fail mcp discoverable, no mandatory sales call, mcp integration available, 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. Vapi leads 87 to 67. Stream misses search discoverable, llms-full.txt / full agent docs, mcp discoverable; Vapi misses mcp discoverable.

Understand is whether an agent can read the docs and work out how the API behaves before calling it. Vapi leads 92 to 31. Stream misses structured api reference, openapi / spec quality, pricing understandable, request examples provided, response examples provided, errors and status codes documented; Vapi misses authentication documented.

Adopt. Vapi leads 50 to 40. Stream misses self-service signup, no mandatory sales call, programmatic credential creation, free trial or free allowance, fast time to first request, mcp integration available; Vapi misses no mandatory sales call, agent-compatible signup flow, official python sdk, cli available, mcp integration available.

Operate. Vapi leads 82 to 35. Stream misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, agent compatibility verified; Vapi misses agent compatibility verified.

Pricing

Stream does not publish a machine-readable starting price. Vapi starts at $0.05/min with no free tier.

Signal by signal

Which to pick

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

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