AssemblyAI
Built by AI experts, AssemblyAI's Speech AI models include accurate speech-to-text for voice data (such as calls, virtual meetings, and podcasts), speaker detection, sentiment analysis, chapter detection, PII redaction, and more. AssemblyAI provides powerful APIs for transcribing and understanding audio data at scale. The platform supports real-time streaming transcription via WebSocket, asynchronous batch transcription, and audio intelligence features including summarization, auto chapters, entity detection, and content safety filtering. SDKs are available for Python, Node.js, Ruby, Java, and Go.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles AssemblyAI the way a machine reads it — 27 machine-readable artifacts across 3 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — AssemblyAI scores 59.2/100 (developing), with a separate agent-readiness read of 49/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile AssemblyAI
Each block below is one kind of artifact we hold for AssemblyAI. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 3
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
AssemblyAI LeMUR API
LeMUR related operations
AssemblyAI Streaming API
Streaming Speech-to-Text
AssemblyAI Transcript API
Transcript related operations
Agent Skills 1
An agent skill packages the how-to for driving these APIs from an assistant — the prompts, the sequence, the guardrails — so the knowledge to use the API travels with it.
Packaged agent skills for driving this provider's APIs from an AI assistant.
assemblyai
AGENT SKILLGraphQL 1
Where a provider ships GraphQL, the schema is the contract. We profile it alongside the REST surface so the whole interface is legible in one place.
GraphQL schemas published by this provider.
AssemblyAI GraphQL API
AssemblyAI is an AI speech-to-text and audio intelligence API. The API covers async and real-time transcription, speaker diarization, sentiment analysis, topic detection, PII re...
GRAPHQLPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Assemblyai Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Assemblyai Finops
FINOPSFeatures 5
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
Speech-to-Text Transcription
High-accuracy transcription of audio files and streams using AssemblyAI's Universal-2 model with support for 99+ languages and custom vocabulary.
Real-Time Streaming Transcription
WebSocket-based streaming transcription for live audio with partial results and final transcripts, supporting call centers, live captioning, and voice applications.
Speaker Diarization
Automatic speaker detection and labeling that identifies who said what in multi-speaker recordings.
Audio Intelligence
Advanced understanding features including sentiment analysis, summarization, auto chapters, entity detection, content safety filtering, and PII redaction.
LeMUR
LeMUR (Leveraging Large Language Models for Understanding Recordings) enables asking questions of audio transcripts using a conversational AI interface built on top of transcrip...
Event Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
AssemblyAI Universal Streaming Speech-to-Text API
AsyncAPI specification for the AssemblyAI Universal Streaming Speech-to-Text WebSocket API (v3). Clients open a WebSocket to `wss://streaming.assemblyai.com/v3/ws`, send raw bin...
ASYNCAPISpectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
AssemblyAI API Rules
SPECTRALSecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Use Cases 5
What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.
What developers build with this provider.
Call Center Analytics
Customer service teams transcribe and analyze customer calls for quality assurance, compliance, agent coaching, and sentiment analysis.
Meeting Intelligence
Enterprises transcribe virtual meetings (Zoom, Teams, Meet) to generate summaries, action items, and searchable archives.
Podcast Processing
Podcast producers transcribe episodes for SEO, accessibility, show notes, and content repurposing.
Voice Application Development
Developers build voice-powered applications using real-time streaming transcription for voice commands, dictation, and conversation interfaces.
Compliance and Legal
Legal and compliance teams transcribe depositions, hearings, and recorded communications with PII redaction and timestamped transcripts.
Integrations 4
Pre-built integrations with other platforms tell you where this provider already fits in a stack.
Pre-built integrations with other platforms and tools.
Twilio
Integration with Twilio Media Streams for transcribing phone calls in real-time using AssemblyAI's streaming API.
Zoom
Integration with Zoom recordings for batch transcription and meeting intelligence processing.
Python SDK
Official Python SDK for AssemblyAI available on PyPI (assemblyai) for easy integration in Python applications.
Node.js SDK
Official Node.js SDK for AssemblyAI available on npm (@assemblyai/sdk) for JavaScript and TypeScript applications.
Resources
Every other property we hold for AssemblyAI — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 2
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 2
The organization behind the API
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