⚡Stack Radar

Speech & Voice Models · Reviewed 22 Oct 2026

AssemblyAI

Speech-to-text and voice AI APIs for developers.

free tier · assemblyai.com ↗

Paid against free › Speech & Voice Models › AssemblyAI

AssemblyAI at a glance
487.1KEstimated total trafficModeled monthly visits2.4KRanking keywordsPublic search sample95/100Technical health15 pages checked10.6KReferring domainsLive backlink summary

Overview

01

Summary

The useful answer before the supporting detail.

AssemblyAI is a Voice AI infrastructure provider offering speech-to-text and speech understanding APIs for developers S31. It solves the problem of building voice-enabled products by providing pre-recorded, streaming, and synchronous transcription, along with features like speaker diarization, sentiment analysis, and PII redaction S1. The main practical value is that developers can integrate production-ready voice AI into their applications via a single API, with options for cloud or self-hosted deployment S11.

02

Product identity and positioning

Name, category, positioning, audience, and first-party claims.

  • Identity: AssemblyAI is a provider of Voice AI infrastructure, including speech-to-text and speech understanding APIs S31.
  • Core purpose: It turns raw audio into structured, actionable intelligence S11.
  • Intended users: Developers building voice-enabled products, such as voice agents, contact center analytics, and clinical documentation S11.
  • Product scope: A platform offering multiple APIs: Pre-recorded, Realtime, Sync, Speech Understanding, Guardrails, Voice Agent, Dictation, and LLM Gateway S31 S1.
  • Positioning: Positioned as "Voice AI infrastructure for builders" S97.
  • Claimed distinction: Claims industry-leading accuracy and low latency, with sub-300ms streaming latency S1 S97.
03

Use cases and audiences

Who the product serves and the jobs it is designed to handle.

AudiencePractical use case
Voice agent developersBuild production-ready voice agents with turn detection and interruption handling S97.
Contact centersPower live agent coaching and compliance monitoring during calls S11.
Clinical documentationOptimize transcription for medical terminology and healthcare conversations S11.
Meeting note toolsGenerate summaries and action items from meetings S1.

Features

09

Features and capabilities

Core functions and evidence-backed product capabilities.

CapabilityWhat it does
Speech-to-TextTranscribes audio and video asynchronously across 99 languages S31.
Streaming Speech-to-TextHandles live audio over WebSocket with ~150ms p50 latency S31.
Speech UnderstandingExtracts insights like summarization, sentiment, and topic detection S31.
GuardrailsProvides PII redaction, content moderation, and profanity filtering S18.
Voice Agent APIManages a speech-to-speech pipeline with STT, LLM, and TTS S31.
Dictation APITranscribes and formats audio up to 20 minutes in one call S31.
LLM GatewayProvides unified access to frontier language models S31.
10

Integrations and ecosystem

Connected products, exports, APIs, and workflow compatibility.

Integration or interfaceTypeWhat it enables
Python SDKSDKIntegrate transcription, streaming, and voice agents into Python codebases S31.
TypeScript SDKSDKIntegrate transcription, streaming, and voice agents into TypeScript codebases S31.
HTTP APIAPIBuild directly against raw HTTP for full control S31.
WebSocket APIAPIHandle live audio streaming S31.
LLM GatewayAPISend transcripts to AI model, AI model, AI model, or open-source models S11.

Pricing

11

Pricing and plans

Published plans, free access, trials, credits, and pricing limitations.

Plan or offerVerified price and billingIncludedLimits
Universal-3.5 Pro$0.21 per audio hour, pay-as-you-go S169Transcription with 18 languages and code switching S169Not established
Universal-2$0.15 per audio hour, pay-as-you-go S169Transcription in 99 languages S169Not established
CustomContact sales S169Custom rate limits and concurrency S169Custom
Free tier$50 free credits, no credit card required S175Not establishedNot established

Competition

12

Competitive landscape

Domains competing for the same organic search demand.

Sampled competitors

CompetitorFirst-page appearancesSampled queriesAverage positionQueries observed
youtube.com423.3assembly ai, assemblyai
aws.amazon.com112assembly ai
reddit.com118assemblyai
g2.com119assembly ai

Website intelligence — Collected evidence

Customers, testimonials, and first-party review claims

No supporting public-page evidence was collected for this category.

Independent review sources discovered

No links to supported independent review platforms were discovered on the collected pages.

14

AI visibility

Measured ChatGPT and Google AI mentions with cited sources.

AI-assistant referral traffic

  • Estimated current generative-AI referral share: 2.4%
MonthSource
—All AI assistants
—All AI assistants
—All AI assistants

Website intelligence — Collected evidence

Site-stated AI capabilities

Page typeEvidenceSource
otherZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/
otherVoice AI infrastructure for buildershttps://www.assemblyai.com/
otherRoute between every LLM from one endpoint with built-in fallback, so you swap models and survive outages without touching your code.https://www.assemblyai.com/
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features
featuresEvery feature runs on the same industry-leading Voice AI models and inference platform behind 800M+ API calls a month, with the accuracy, availability, and compliance controls enterprise deployments require.https://www.assemblyai.com/features
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features/automatic-language-detection
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features/content-moderation
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features/entity-detection
featuresSpeech Understanding API Guardrails and Safety LLM Gatewayhttps://www.assemblyai.com/features
featuresSelf Hosted Voice AI Cloudhttps://www.assemblyai.com/features
featuresVoice Agents AI Notetakers Call Analytics Medical Transcription Dictation Agent Assist AI Scribeshttps://www.assemblyai.com/features
featuresTop Voice AI companies are building with Assembly.https://www.assemblyai.com/features
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features
featuresSpeech Understanding API Guardrails and Safety LLM Gatewayhttps://www.assemblyai.com/features/automatic-language-detection
featuresSelf Hosted Voice AI Cloudhttps://www.assemblyai.com/features/automatic-language-detection
featuresVoice Agents AI Notetakers Call Analytics Medical Transcription Dictation Agent Assist AI Scribeshttps://www.assemblyai.com/features/automatic-language-detection
featuresTop Voice AI companies are building with Assembly.https://www.assemblyai.com/features/automatic-language-detection
featuresZoom leverages AssemblyAI to help advance its AI research and development.https://www.assemblyai.com/features/automatic-language-detection
featuresSpeech Understanding API Guardrails and Safety LLM Gatewayhttps://www.assemblyai.com/features/content-moderation
featuresSelf Hosted Voice AI Cloudhttps://www.assemblyai.com/features/content-moderation

These are first-party product claims, not independent measurements of AI-search visibility.

15

Marketing opportunities

Actions calculated directly from the collected evidence.

OpportunityRecommended actionEvidence
Competitor gapReview the sampled queries where youtube.com appears.4 first-page appearances across assembly ai, assemblyai

Website intelligence — Collected evidence

Website evidence gaps

  • integrations: no usable public page was collected; verify whether the site publishes this evidence.
  • customers: no usable public page was collected; verify whether the site publishes this evidence.
  • reviews: no usable public page was collected; verify whether the site publishes this evidence.
  • changes: no usable public page was collected; verify whether the site publishes this evidence.
  • identity: no usable public page was collected; verify whether the site publishes this evidence.
  • technical: no usable public page was collected; verify whether the site publishes this evidence.

Trust and proof

16

Customers, proof, and reviews

Published proof, customer signals, and review evidence.

Independent reviews

PlatformPageHow it was foundNote
G2AssemblyAI - Speech to Text API Reviews & Product DetailsGrounded web searchthings Speech to Text related. We love the ease-of-use with integration, extremely clear documentation (implementation), phenomenal support, and accuracy of the speech to text recognition. Assembly has kept up with our startup's high
G2 AIAssemblyAI - Speech to Text API Reviews & Product Details / G2 AIGrounded web search- ✗ Reviewers experienced minor issues with the transcription quality, the speed of the service, the cost, the speaker differentiation, and the lack of certain features such as summarization for all languages and improved support for non-English languages.
FeaturedCustomers41 AssemblyAI Customer Reviews & ReferencesGrounded web searchRead 11 AssemblyAI reviews and testimonials from customers, explore 28 case studies and customer success stories, and watch 2 customer videos to see why companies chose AssemblyAI as their Speech Recognition Software
Product HuntAssemblyAI Reviews / Product HuntGrounded web searchReviewers mostly praise AssemblyAI for accurate transcription, strong formatting of names and numbers, and developer-friendly APIs and docs that make it quick to test and ship. Users also call out useful extras like Auto Chapters and sentiment analysis, while founders of IFTTT, ClinicFrame, and Nugget AI say it helps them summarize audio, handle medical conversations, and run low-latency streaming with solid speaker separation. Criticism is limited but notable: one user disliked billing friction
AWS MarketplaceAWS Marketplace: AssemblyAI ReviewsGrounded web searchIt is very accurate, fast, and easy to use. It has many features and is perfect for developers, tech companies ... of voice data automatically. With the API system, you can create your own software and customize it as you wish. I use the APIs with my own

Customer proof

Proof typeNamed customer or sourceEvidence
Case studyDovetailcustomer case study — For Dovetail, this partnership meant significant results: - 36% improvement in word error rate (WER) - ~10% improvement in speaker diarization (speaker labels) - Notable increase in customer sentiment tied to transcri… (How Dovetail improved WER by 36% with AssemblyAI to power continuous customer intelligence)
Case studyGraincustomer case study — After integrating AssemblyAI's Voice AI models into its workflows, Grain saw its customer satisfaction increase by 12%. (How Grain increased customer satisfaction by 12% after integrating AssemblyAI)
Case studyassemblyai.comcustomer case study — After conducting an in-depth comparison of transcription providers, Dovetail chose AssemblyAI. (Enhanced diarization + Dovetail case study + G2 wins / Newsletter / AssemblyAI)
Case studyusepylon.comcustomer case study — - 97% reduction in First Response Time, from 15 minutes to 23 seconds ... (How AssemblyAI scaled 24/7 support with AI agents)

Independent mentions

  • Customers — Summary AssemblyAI serves startups, growth-stage companies, and enterprises building products on speech. Customer stories highlight production use cases, model quality, scale, developer experience, and support.

External links were grounded in one live web search. Search snippets are leads, not independently scraped page content; rejected links remain available in Review evidence.

17

Company, security, and trust

Ownership, policies, security signals, and public trust evidence.

SignalFindingSource
Company and ownershipWe're all on the same team – AssemblyAI. Regardless of the department or team we work in, we recognize that as a startup, individual and team success comes as a byproduct of AssemblyAI's success. We are collaborative witsource
Contact and supportStandardize dates, phone numbers, currency, and URLs in the transcript itself, ready for the systems downstream.source
Legal and privacyWhen you visit our Websites and other web content pages (hereinafter collectively, “Websites”), we may (on our own or through a third-party) place a cookie on your device. Such cookies on their own rarely contain sufficisource
Security and complianceSOC 2 Type 2 and GDPR, with BAA availablesource
Uptime and status pageGlobal redundancy, enterprise-grade uptime, and 2 million hours of audio processed every day. The Voice AI infrastructure your product can depend on at any scale.source
Domain registered2016-12-24—
Domain expires2026-12-24—

Every trust signal above is backed by a collected page or a registration record.

18

Documentation and product updates

Help resources, product guidance, and visible changes over time.

Resource or updateTypeWhat is availableDate or freshness
AssemblyAI DocumentationDocumentationBuild with our Voice AI Infrastructure (source)Not dated
AssemblyAI / AI models to transcribe and understand speechStatus pagePublic service-status information. (source)Not dated
Lower latency, lower cost, more possibilities / AssemblyAIGuidePublic tutorials and product guidance. (source)Not dated

Not found in the collected public sources: public roadmap, changelog or release notes, separate help center or knowledge base.

Technical

19

Technical and delivery signals

Delivery model, platforms, API, data ownership, reliability claims and release activity.

SignalFindingSource
Delivery model (cloud, self-hosted, desktop, browser extension)Available as managed cloud or self-hosted deployment S1.S1
Platforms and appsWeb-based API; no native mobile or desktop apps mentioned S31.S31
API and extensibility (API, SDK, webhooks, MCP, plugins)Provides HTTP and WebSocket APIs, plus Python and TypeScript SDKs S31.S31
Data ownership and exportNot published on the collected pages.—
Performance and reliability claimsClaims sub-300ms latency for streaming and voice agents S1.S1
Release activityNot published on the collected pages.—
20

Measured infrastructure

Domain, certificate, and hosting signals, measured directly.

SignalFinding
Domain registered2016-12-24 — NameCheap, Inc.
Domain expires2026-12-24
TLS certificateLet's Encrypt, valid, expires 2026-12-30
Security headersHSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy
Server headerVercel
Mail handled byaspmx.l.google.com, alt1.aspmx.l.google.com
Nameserversns-18.awsdns-02.com, ns-1906.awsdns-46.co.uk

Not measurable: wayback: rate limited by archive.org, ladder stopped after 1 probe(s); rdap: exceeded the overall budget; wayback: exceeded the overall budget; tls: exceeded the overall budget; dns: exceeded the overall budget; headers: exceeded the overall budget. A gap here means the lookup was unavailable, not that the finding is negative.

21

Technical site audit

A bounded multi-page crawl with page-level issues and URLs.

Scout — Bounded technical crawl

  • Pages crawled: 15 of 15 maximum
  • Technical health: 95/100
  • Critical issues: 0
  • Warnings: 8
  • Notices: 16

Issues

SeverityIssueValueAffected URL
noticeMeta description length should be reviewed15https://www.assemblyai.com/
noticeImages are missing alt text6https://www.assemblyai.com/
warningTitle length should be reviewed110https://www.assemblyai.com/blog/voice-standard-bench
noticeMeta description length should be reviewed10https://www.assemblyai.com/blog/voice-standard-bench
noticeImages are missing alt text2https://www.assemblyai.com/blog/voice-standard-bench
noticeMeta description length should be reviewed15https://www.assemblyai.com/
noticeImages are missing alt text6https://www.assemblyai.com/
warningPage should have one primary H10https://www.assemblyai.com/products
noticeImages are missing alt text3https://www.assemblyai.com/products
noticeMeta description length should be reviewed10https://www.assemblyai.com/products/speech-to-text
noticeMeta description length should be reviewed39https://www.assemblyai.com/products/streaming-speech-to-text
noticeMeta description length should be reviewed171https://www.assemblyai.com/products/sync-speech-to-text
noticeImages are missing alt text4https://www.assemblyai.com/products/speech-understanding
noticeImages are missing alt text2https://www.assemblyai.com/products/voice-agent-api
noticeImages are missing alt text1https://www.assemblyai.com/products/dictation-api
noticeMeta description length should be reviewed178https://www.assemblyai.com/products/text-to-speech
noticeMeta description length should be reviewed14https://www.assemblyai.com/deployments/self-hosted
noticeImages are missing alt text4https://www.assemblyai.com/deployments/cloud
warningDuplicate title in audit sample2https://www.assemblyai.com/
warningDuplicate title in audit sample2https://www.assemblyai.com/
warningDuplicate meta description in audit sample2https://www.assemblyai.com/
warningDuplicate meta description in audit sample2https://www.assemblyai.com/
warningDuplicate meta description in audit sample2https://www.assemblyai.com/blog/voice-standard-bench
warningDuplicate meta description in audit sample2https://www.assemblyai.com/products/speech-to-text

Crawled pages

StatusTitleH1sWordsResponseURL
200AssemblyAI \AI models to transcribe and understand speech1155167 ms
200Introducing Voice Standard Bench: 50+ models, ranked by performance, speed and cost on real audio \AssemblyAI1317644 ms
200AssemblyAI \AI models to transcribe and understand speech1155171 ms
200Products Overview \AssemblyAI0148249 ms
200Pre-recorded Speech-to-Text API \AssemblyAI1185060 ms
200Realtime Speech-to-Text API \AssemblyAI1179677 ms
200Sync Speech-to-Text API \AssemblyAI1205769 ms
200Speech Understanding API \AssemblyAI1216846 ms
200Voice AI Guardrails \AssemblyAI1197785 ms
200LLM Gateway \AssemblyAI13170463 ms
200Voice Agent API \AssemblyAI1216059 ms
200Dictation API \Finished text in one call \AssemblyAI12060
200Text-to-Speech API for Voice Agents \AssemblyAI1116039 ms
200Self-hosted Voice AI \AssemblyAI1104122 ms
200AssemblyAI Cloud \AssemblyAI1115045 ms

This is a bounded Scout crawl. Core Web Vitals and Lighthouse scores are not claimed unless a dedicated performance audit is connected.

22

Search Console and Analytics

First-party search and behavioral data connection state.

Modeled acquisition channels

ChannelEstimated share
direct63.8%
search21.1%
search organic17.7%
search paid3.4%
social8.3%
social organic8.1%
social paid0.2%
referrals3.0%
paid referrals0.2%
mail1.1%
gen ai2.4%
affiliate0.0%
other0.0%

First-party connections

IntegrationStatusData available after connection
Google Search ConsoleNot connectedClicks, impressions, CTR, average position, queries, pages, countries, and devices
Google AnalyticsNot connectedOrganic sessions, engagement, landing pages, conversions, geography, and devices

No first-party Search Console or Analytics numbers are shown until the site owner authorizes the corresponding Google account. Scout traffic model values above are modeled estimates, not private analytics totals.

Limits and method

23

Limitations and open questions

Known constraints and missing evidence from the collected pages.

The collected pages do not mention specific competitors. Evidence gaps include lack of detailed pricing for add-on features, no explicit data retention policies, and no independent review ratings. Open questions remain about the exact free tier limits and the full scope of self-hosted deployment options.

24

Sources, method, and limitations

Evidence inventory, collection method, provider use, and constraints.

This report is based on 15 collected pages from assemblyai.com, including product, features, pricing, and documentation pages. The evidence catalog includes 180 entries from these pages. External proof search was performed but no additional verification was completed. Limitations: some pages were not fully rendered, and pricing details were supplemented by an authoritative pricing reference.

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