Vapivapi.ai
Vapi's API design is a genuine strength — the contract is machine-readable and schemas are well-typed, giving partners a solid foundation to build on. The critical gaps are in developer experience and agent usability: partners currently lack a self-service portal with complete endpoint descriptions, a sandbox to safely explore the API, and runnable collections that agents can use as executable context.
API DesignA clean, typed, well-governed API contract agents can reason about3 pass2 warn0 fail84A
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Auth declared & discoverablevia spec | 25/25 | Authentication required (global or on every operation). Investigated: spec 100%, docs 100%. | Agents can only authenticate when auth is declared, scoped, and discoverable. |
| warn | Machine-readable, versioned contractvia spec | 18.8/25 | info.version="1.0" set but no versioning scheme (URL / header / media type) detected. Investigated: spec 75%, docs 50%. | A current OpenAPI version with a declared versioning scheme lets agents reason about the contract. |
| pass | Security & governance hygienevia spec | 15/15 | No credential-shaped strings detected in spec. Investigated: spec 100%, wellknown 0%. | No leaked secrets, no critical lint violations, no OWASP API Top-10 spec smells, and a published vulnerability-disclosure channel. |
| warn | Schema coverage & depthvia spec | 12.5/25 | Max schema nesting depth: 16 (≥15 = deep). Investigated: spec 50%. | Typed, complete request/response schemas are what make agent function-calling possible. |
| pass | Example coveragevia docs | 10/10 | Code samples present on 3/20 pages across 1 language(s); broader multi-language coverage missing. Investigated: docs 100%, spec 0%. | Examples carry shape semantics schemas under-specify — for humans and agents alike. |
Developer ExperienceThe context both developers and agents need to integrate fast — onboarding, code samples, complete descriptions and worked examples2 pass1 warn2 fail57D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Code samples in docsvia docs | 18/18 | Code samples present on 3/20 pages across 1 language(s); broader multi-language coverage missing. Investigated: docs 100%. | Multi-language samples shorten time-to-first-call. |
| pass | Changelog publishedvia sdk | 13/13 | Newest official SDK activity 1 day(s) ago. Investigated: sdk 100%, spec 0%, docs 0%. | A published changelog lets partners track changes without surprise. |
| warn | Quickstart presentvia docs | 12.5/25 | Quickstart page reachable (1 variants scanned starting at https://docs.vapi.ai/quickstart) but no runnable code sample detected in HTML or .md variant. Investigated: docs 50%. | A quickstart is the fastest path from landing page to first successful call. |
| fail | Self-service developer portalvia docs | 0/29 | No signup page detected across conventional paths (/signup, /sign-up, /register, /get-started, /console/signup, /dashboard/signup, /try, /try-free, /free, /free-trial, /start, /start-free). Investigated: docs 0%. | Self-serve key/account creation is the fast first call for partners, with no sales gate. |
| fail | Description completenessvia spec | 0/15 | 47% description completeness. Investigated: spec 0%. | Complete descriptions are the context humans and agents need to use endpoints. |
Agent DiscoveryPartners and their agents can find your APIs — llms.txt, registries, crawlable and reachable docs2 pass0 warn0 fail100A+
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Registry & SDK presencevia cli | 28/28 | Official CLI at VapiAI/cli with published releases (installable). Investigated: cli 100%, docs 0%. | Listing in MCP registries and publishing SDKs puts the API where agents and their tooling look. |
| pass | Crawlable / AEOvia wellknown | 12/12 | Docs paths crawlable by all monitored AI agents. Investigated: wellknown 100%. | Bots allowed plus a fresh sitemap make docs findable by agent crawlers. |
| na | llms.txt present, valid & comprehensive | —/30 | No surface produced evidence for this capability in this run. | A valid, comprehensive llms.txt is the machine-readable entry point for agents. |
| na | Docs reachable, not hard auth-gated | —/30 | No surface produced evidence for this capability in this run. | Agents can only index and fetch docs they can reach — past auth gates and over correct HTTP semantics. |
Agent UnderstandingAgents can correctly interpret your APIs — machine-readable errors, consistent descriptions, structured data, parseable docs2 pass0 warn2 fail79B
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Machine-readable errors (RFC 9457)via spec | 28/28 | Only 2 distinct 4xx/5xx codes documented (plus 0 "default" catch-all responses). Investigated: spec 100%, docs 100%. | RFC 9457 problem details and a documented error-code inventory let agents parse failures without burning tokens. |
| pass | Operation purpose clarityvia spec | 25/25 | 92% of operations have a clear summary + operationId an agent can select on. Investigated: spec 100%. | Agents select the right endpoint from its summary + operationId; clear, named operations make tool-selection reliable — the strongest driver of correct tool choice. |
| fail | Agent instructions file (AGENTS.md)via wellknown | 0/10 | No AGENTS.md at the site root or /.well-known/. Investigated: wellknown 0%. | An AGENTS.md gives coding agents explicit setup, auth, and usage instructions to interpret and operate the API — beyond llms.txt's link index. |
| fail | Docs structured datavia docs | 0/8 | Neither JSON-LD nor OpenGraph/meta tags detected across 2 assessed pages (2 JS-rendered). Investigated: docs 0%. | Structured data (JSON-LD/schema.org) on docs pages gives agents an unambiguous parse target and is what answer engines cite. Detected on the JS-rendered head (Firecrawl) for a bounded page budget, so JS-injected JSON-LD is now caught; pages we can't render are excluded rather than failed. |
| na | Agent-navigable, token-efficient docs | —/22 | No surface produced evidence for this capability in this run. | Server-rendered, clean, small-footprint docs are what an agent can cheaply fetch and parse correctly. |
| na | Description consistency across surfaces | —/7 | Only 0 surface description(s) with ≥6 tokens available; need at least 2 to compare. | Every surface tells the same story about what the product is. |
Agent UsabilityAgents have the context to use your APIs reliably, not just find them2 pass0 warn3 fail58D
| Signal | Points | Findings | Rationale | |
|---|---|---|---|---|
| pass | Rate-limit signalingvia spec | 22/22 | rate-limit behavior documented in the docs site at https://docs.vapi.ai/providers/model/azure-openai. Investigated: spec 100%, docs 100%. | Machine-readable rate-limit headers let agents throttle adaptively. |
| pass | Pagination documented & consistentvia spec | 22/22 | Pagination params detected on 17 list endpoint(s). Investigated: spec 100%, docs 100%. | Consistent, documented pagination lets agents traverse collections. |
| fail | Idempotency documentedvia spec | 0/27 | 0% of mutating operations document idempotency. Investigated: spec 0%, docs 0%. | Documented idempotency lets agents retry safely. |
| fail | Sandbox separationvia spec | 0/20 | No sandbox/test server declared across 1 server entries; no test-key prefixes documented. Investigated: spec 0%, docs 0%. | An isolated environment lets agents exercise destructive operations safely. |
| fail | Runnable collection with test scriptsvia platform | 0/9 | No public Postman workspace discovered for the org. Investigated: platform 0%. | A public, maintained collection with assertions is runnable truth agents validate against. |
Resources Discovered
The public resources we found for Vapi — the evidence behind the score. All discovered from public sources; nothing here requires access to your systems.
| APIs analyzed | 1 — Vapi API |
|---|