Fixie

Fixie is the company behind Ultravox Realtime, a speech-native voice AI platform for building natural, low-latency conversational voice agents. Rather than transcribing speech to text first, Ultravox processes audio directly to preserve tone, cadence, and pitch while cutting latency. The Ultravox Realtime REST API (api.ultravox.ai) lets developers create reusable agents, start and manage calls, define custom and built-in tools, clone and manage voices, build RAG corpora, wire telephony (Twilio, Telnyx, Plivo, SIP), and subscribe to call-lifecycle webhooks. Client SDKs ship for JavaScript, Python, Flutter/Dart, React Native, Kotlin/Android, and Swift/iOS. Fixie was backed by Redpoint Ventures; fixie.ai now redirects to ultravox.ai and its open models are published under the fixie-ai organization on Hugging Face.

Fixie publishes 14 API contracts indexed on the APIs.io network, including Accounts API, Agents API, API Keys API, and 11 more. Tagged areas include Company, Voice AI, Conversational AI, Real-Time, and Speech.

The Fixie catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

Fixie’s developer surface includes changelog, documentation, API reference, getting-started guide, engineering blog, pricing, signup flow, and 20 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

60.8/100 strong ▬ flat Agent 28/100 agent aware Front door AI 6/6 dominant Heartbeat 61/100 alive saas Full breakdown ↓
scored 2026-11-02 · rubric v0.26.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract 2 Agent Skills

Company Voice AI Conversational AI Real-Time Speech Agents Telephony Machine Learning SIP Webhook

What this lets a business do 2

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Developer Platform & API Ecosystem Management

BC-4270

Webhooksapi_keys

POST /api/webhooks POST /api/api_keys

AI Model Services

AE-110

Corpora

POST /api/corpora POST /api/corpora/{corpus_id}/query

Kin Score

Kin Score How this is scored →
scored 2026-11-02 · rubric v0.26.0

Composite quality — 60.8/100 · strong

Contract Quality 10.1 / 19

Developer Ergonomics 9.9 / 15

Access Clarity 13.8 / 15

Operational Transparency 4.1 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 4.1 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the AI & Biometrics regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Show this score on your site.

It updates itself when the score changes. Paste this where you link to your API docs:

<a href="https://apis.io/providers/fixie/"><img src="https://apis.io/badge/fixie/card.svg" alt="Fixie on APIs.io — Kin Score by API Evangelist"></a>

Other styles, a README pill and a shields.io endpoint are on the badge page.

Raise your score.

Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)

6 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 53.9 — up to +11.5 composite points
Contract Governance scores 18.2 — up to +9.8 composite points
Operational Transparency scores 42.1 — up to +7.5 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/fixie/apis.yml: open an issue on github.com/api-evangelist/fixie to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Speech and Voice AI	covered	26.8 (thin)	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

APIs 14

Individual APIs this provider publishes, each with its own machine-readable definition.

Fixie Accounts API

The accounts API from Fixie — 9 operation(s) for accounts.

Fixie Agents API

The agents API from Fixie — 9 operation(s) for agents.

Fixie API Keys API

The api_keys API from Fixie — 2 operation(s) for api_keys.

Fixie Call Throttles API

The call_throttles API from Fixie — 2 operation(s) for call_throttles.

Fixie Calls API

The calls API from Fixie — 13 operation(s) for calls.

Fixie Corpora API

The corpora API from Fixie — 8 operation(s) for corpora.

Fixie Deleted Calls API

The deleted_calls API from Fixie — 2 operation(s) for deleted_calls.

Fixie Models API

The models API from Fixie — 1 operation(s) for models.

Fixie Schema API

The schema API from Fixie — 1 operation(s) for schema.

Fixie Sip API

The sip API from Fixie — 3 operation(s) for sip.

Fixie Telephony Configs API

The telephony_configs API from Fixie — 3 operation(s) for telephony_configs.

Fixie Tools API

The tools API from Fixie — 4 operation(s) for tools.

Fixie Voices API

The voices API from Fixie — 4 operation(s) for voices.

Fixie Webhooks API

The webhooks API from Fixie — 2 operation(s) for webhooks.

Scroll for all 14

Open Collections 14

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Ultravox accounts API

OPEN COLLECTION

Ultravox accounts agents API

OPEN COLLECTION

Ultravox accounts api_keys API

OPEN COLLECTION

Ultravox accounts call_throttles API

OPEN COLLECTION

Ultravox accounts calls API

OPEN COLLECTION

Ultravox accounts corpora API

OPEN COLLECTION

Ultravox accounts deleted_calls API

OPEN COLLECTION

Ultravox accounts models API

OPEN COLLECTION

Ultravox accounts schema API

OPEN COLLECTION

Ultravox accounts sip API

OPEN COLLECTION

Ultravox accounts telephony_configs API

OPEN COLLECTION

Ultravox accounts tools API

OPEN COLLECTION

Ultravox accounts voices API

OPEN COLLECTION

Ultravox accounts webhooks API

OPEN COLLECTION

Scroll for all 14

Agent Skills 2

Packaged agent skills for driving this provider's APIs from an AI assistant.

Create a voice agent and start a call

AGENT SKILL

Subscribe to call webhooks and fetch recordings

AGENT SKILL

Pricing Plans 2

Published pricing tiers and plan structures.

Fixie Plans Pricing

7 plans

PLANS

Fixie Price Estimates

0 plans

PLANS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Fixie Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Fixie Webhooks

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Fixie API Rules

50 rules · 38 errors 10 warnings 2 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Fixie Ultravox Overlay

2 actions · update · fixie-ultravox-openapi-original.yml

DERIVED

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Fixie Authentication

apiKey · 1 scheme

SECURITY

Fixie Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Fixie Trust Center

trust center published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Fixie Agentic Access

114 operations · 57 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Webhooks

Webhooks

Build 3

SDKs, sample code, and the tooling you integrate with

Packages

Packages

SDKs

SDKs

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

TrustCenter

TrustCenter

Operate 4

Status, limits, changes, and where to get help

ChangeLog

StatusPage

Deprecation

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 2

The organization behind the API

Blog

Blog

Website

Website

Other 2

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Overlay

Overlay

Source (apis.yml)

aid: fixie
name: Fixie
description: Fixie is the company behind Ultravox Realtime, a speech-native voice AI platform for building natural, low-latency
  conversational voice agents. Rather than transcribing speech to text first, Ultravox processes audio directly to preserve
  tone, cadence, and pitch while cutting latency. The Ultravox Realtime REST API (api.ultravox.ai) lets developers create
  reusable agents, start and manage calls, define custom and built-in tools, clone and manage voices, build RAG corpora, wire
  telephony (Twilio, Telnyx, Plivo, SIP), and subscribe to call-lifecycle webhooks. Client SDKs ship for JavaScript, Python,
  Flutter/Dart, React Native, Kotlin/Android, and Swift/iOS. Fixie was backed by Redpoint Ventures; fixie.ai now redirects
  to ultravox.ai and its open models are published under the fixie-ai organization on Hugging Face.
url: https://raw.githubusercontent.com/api-evangelist/fixie/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- redpoint-ventures
x-tier: profiled
x-tier-reason: enriched-from-public-api
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-02'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-19'
image: https://raw.githubusercontent.com/api-evangelist/fixie/refs/heads/main/openapi/fixie-ultravox-openapi-original.yml
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-03
x-docs-hosting: vercel
tags:
- Company
- Voice AI
- Conversational AI
- Real-Time
- Speech
- Agents
- Telephony
- Machine Learning
- SIP
- Webhook
tags_raw:
- Company
- Voice AI
- Conversational AI
- Real-time
- Speech
- Agents
- Telephony
- Machine Learning
- SIP
- Webhooks
- Machine-Learning
apis:
- aid: fixie:fixie-accounts-api
  name: Fixie Accounts API
  description: The accounts API from Fixie — 9 operation(s) for accounts.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Account
  tags_raw:
  - accounts
  properties:
  - type: OpenAPI
    url: openapi/fixie-accounts-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-agents-api
  name: Fixie Agents API
  description: The agents API from Fixie — 9 operation(s) for agents.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Agents
  tags_raw:
  - agents
  properties:
  - type: OpenAPI
    url: openapi/fixie-agents-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-api-keys-api
  name: Fixie API Keys API
  description: The api_keys API from Fixie — 2 operation(s) for api_keys.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - APIKeys
  tags_raw:
  - api_keys
  properties:
  - type: OpenAPI
    url: openapi/fixie-api-keys-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-call-throttles-api
  name: Fixie Call Throttles API
  description: The call_throttles API from Fixie — 2 operation(s) for call_throttles.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags: []
  tags_raw:
  - call_throttles
  properties:
  - type: OpenAPI
    url: openapi/fixie-call-throttles-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-calls-api
  name: Fixie Calls API
  description: The calls API from Fixie — 13 operation(s) for calls.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Calls
  tags_raw:
  - calls
  properties:
  - type: OpenAPI
    url: openapi/fixie-calls-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-corpora-api
  name: Fixie Corpora API
  description: The corpora API from Fixie — 8 operation(s) for corpora.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Corpora
  tags_raw:
  - corpora
  properties:
  - type: OpenAPI
    url: openapi/fixie-corpora-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-deleted-calls-api
  name: Fixie Deleted Calls API
  description: The deleted_calls API from Fixie — 2 operation(s) for deleted_calls.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags: []
  tags_raw:
  - deleted_calls
  properties:
  - type: OpenAPI
    url: openapi/fixie-deleted-calls-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-models-api
  name: Fixie Models API
  description: The models API from Fixie — 1 operation(s) for models.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Models
  tags_raw:
  - models
  properties:
  - type: OpenAPI
    url: openapi/fixie-models-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-schema-api
  name: Fixie Schema API
  description: The schema API from Fixie — 1 operation(s) for schema.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Schema
  tags_raw:
  - schema
  properties:
  - type: OpenAPI
    url: openapi/fixie-schema-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-sip-api
  name: Fixie Sip API
  description: The sip API from Fixie — 3 operation(s) for sip.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - SIP
  tags_raw:
  - sip
  properties:
  - type: OpenAPI
    url: openapi/fixie-sip-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-telephony-configs-api
  name: Fixie Telephony Configs API
  description: The telephony_configs API from Fixie — 3 operation(s) for telephony_configs.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags: []
  tags_raw:
  - telephony_configs
  properties:
  - type: OpenAPI
    url: openapi/fixie-telephony-configs-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-tools-api
  name: Fixie Tools API
  description: The tools API from Fixie — 4 operation(s) for tools.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Tools
  tags_raw:
  - tools
  properties:
  - type: OpenAPI
    url: openapi/fixie-tools-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-voices-api
  name: Fixie Voices API
  description: The voices API from Fixie — 4 operation(s) for voices.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Voice
  tags_raw:
  - voices
  properties:
  - type: OpenAPI
    url: openapi/fixie-voices-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
- aid: fixie:fixie-webhooks-api
  name: Fixie Webhooks API
  description: The webhooks API from Fixie — 2 operation(s) for webhooks.
  humanURL: https://docs.ultravox.ai/
  baseURL: https://api.ultravox.ai/api
  tags:
  - Webhook
  tags_raw:
  - webhooks
  properties:
  - type: OpenAPI
    url: openapi/fixie-webhooks-api-openapi.yml
  - type: Authentication
    url: authentication/fixie-authentication.yml
  - type: AgenticAccess
    url: agentic-access/fixie-agentic-access.yml
  - type: Conventions
    url: conventions/fixie-conventions.yml
  - type: ErrorCatalog
    url: errors/fixie-problem-types.yml
  - type: Lifecycle
    url: lifecycle/fixie-lifecycle.yml
  - type: DataModel
    url: data-model/fixie-data-model.yml
  - type: Conformance
    url: conformance/fixie-conformance.yml
  - type: AsyncAPI
    url: asyncapi/fixie-webhooks.yml
  - type: Webhooks
    url: asyncapi/fixie-webhooks.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Plans
  url: plans/fixie-plans-pricing.yml
- type: CapabilityMap
  url: capabilities/fixie-capability-edges.yml
  name: Fixie Business Capability Map
- type: X-MCPServerCandidate
  url: mcp/fixie-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- type: Overlay
  url: overlays/fixie-ultravox-overlay.yaml
- type: DomainSecurity
  url: security/fixie-domain-security.yml
- type: TrustCenter
  url: security/fixie-trust-center.yml
- type: Packages
  url: packages/fixie-packages.yml
- type: SDKs
  url: packages/fixie-packages.yml
- type: ChangeLog
  url: changelog/fixie-changelog.yml
- type: AgentSkill
  url: skills/_index.yml
- type: LLMsTxt
  url: llms/fixie-llms.txt
- type: StatusPage
  url: https://status.ultravox.ai
- type: Deprecation
  url: https://docs.ultravox.ai/changelog/deprecation
- type: Webhooks
  url: asyncapi/fixie-webhooks.yml
- type: DeveloperPortal
  url: https://docs.ultravox.ai/
- type: Documentation
  url: https://docs.ultravox.ai/
- type: APIReference
  url: https://docs.ultravox.ai/api-reference
- type: GettingStarted
  url: https://docs.ultravox.ai/gettingstarted/quickstart/agent-console
- type: GitHubOrganization
  url: https://github.com/fixie-ai
- type: Blog
  url: https://ultravox.ai/blog
- type: Pricing
  url: https://ultravox.ai/pricing
- type: SignUp
  url: https://app.ultravox.ai
- type: Login
  url: https://app.ultravox.ai
- type: TermsOfService
  url: https://ultravox.ai/terms
- type: PrivacyPolicy
  url: https://ultravox.ai/privacy
- type: Support
  url: mailto:hello@ultravox.ai
- type: Website
  url: https://ultravox.ai/
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

Fixie API — frequently asked questions

Does Fixie have an API?

Yes. APIs.io lists 14 APIs from Fixie, including Fixie Accounts API, Fixie Agents API and Fixie API Keys API, and 11 more.

Is there an OpenAPI specification for the Fixie API?

Yes. APIs.io indexes 14 OpenAPI specifications for Fixie, each linked for download from this page.

How do I authenticate with the Fixie API?

Fixie uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Fixie Authentication.

How much does the Fixie API cost?

APIs.io lists 7 pricing plans for Fixie, with each plan's price, limits and inclusions under Pricing Plans on this page.

Is the Fixie API ready for AI agents?

Fixie has a Kin Score of 60.8 out of 100 (strong) and an Agent Readiness score of 28.1 (agent-aware), scored by API Evangelist on 2026-11-02.

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/fixie"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/fixie/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/fixie/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.