AssemblyAI

assemblyai.com
AI & Machine Learning
Weekend Project

AI models to transcribe and understand speech

How to Replace AssemblyAI

Overview

AssemblyAI provides speech-to-text and speech understanding AI models for building Voice AI applications. The platform enables developers to transcribe audio, understand spoken content, and power voice agents with industry-leading accuracy and reliability. It serves thousands of companies processing 600M+ inference calls monthly with easy-to-use APIs and no long-term contracts.

Features

38 features across 17 categories

AI Integration(1)

LLM GatewayAI

Unified voice-to-intelligence workflow unifying speech transcription with LLM capabilities in one API

Also in: Apify, Synthesia, Pendo

AI Model(3)

Universal-2 ModelAI

High-accuracy speech model supporting 99 languages with strong out-of-the-box performance for general-purpose use cases

Universal-3 Pro ModelAIPremium

Most advanced speech language model with prompt-based architecture for deeper contextual understanding and domain-specific customization

Universal-Streaming ModelAI

Ultra-fast, ultra-accurate real-time transcription model designed for voice agents with built-in turn detection and unlimited concurrency

Also in: Deepgram, DeepL

Applications(1)

Voice Agent SupportAI

Built-in features and capabilities designed specifically for building voice agent applications

Compliance(2)

EU Data ResidencyPremium

Data storage and processing within EU for GDPR compliance

HIPAA CompliancePremium

Business Associate Agreement and HIPAA compliance for healthcare applications

Also in: Insider CDP, Airtable, 1Password

Content Moderation(2)

Content ModerationAIPremium

Detect sensitive content in audio and video files including hate speech, violence, sensitive social issues, alcohol, and drugs

Profanity FilteringAI

Automatically filter out profanity from transcripts

Core Transcription(2)

Speech-to-Text (Pre-recorded)AI

Transcribe pre-recorded audio and video files with high accuracy using Universal models with language detection and formatting

Streaming Speech-to-TextAI

Real-time transcription of live audio and video with ultra-low latency and high accuracy

Also in: GoTranscript

Customization(3)

Custom Spelling

Define custom spelling for words to ensure accurate transcription of specialized terminology

Keyterms PromptingAI

Provide up to 1,000 words or phrases to improve transcription accuracy for specific terminology

Plain Language InstructionsAI

Control transcription behavior with plain language prompts to provide context and tag audio events

Also in: monday.com, Obsidian, Smartsheet

Developer Tools(2)

API Documentation

Comprehensive developer documentation for API integration and implementation

No-code Playground

Test AI models without code in an interactive playground environment

Also in: Jobber, Hugging Face, 1Password

Infrastructure(1)

Self-hosted DeploymentsPremium

On-premises, EU-based, and VPC deployment options for maximum security and control

Integration(1)

LiveKit SDK Integration

Integration with LiveKit SDK for building voice agents

Localization(1)

Multi-language StreamingAI

Real-time transcription in multiple languages including English, Spanish, French, German, Italian, and Portuguese

Security/Privacy(2)

PII Audio RedactionAIPremium

Identify and remove Personally Identifiable Information such as phone numbers and social security numbers from audio files

PII Text RedactionAIPremium

Identify and remove Personally Identifiable Information from transcription text before returning to user

Speech Processing(1)

End-of-Turn DetectionAI

Advanced detection for next-gen end-of-turn controls in streaming transcription

Speech Understanding(6)

Entity DetectionAI

Identify a wide range of entities spoken in audio files such as person names, company names, email addresses, dates, and locations

Language DetectionAI

Automatically detect language in multilingual speech

Sentiment AnalysisAI

Detect the sentiment of each sentence of speech in audio files

Speaker DiarizationAI

Detect multiple speakers in audio and segment transcript into utterances, showing what each speaker said

Speaker IdentificationAI

Identify speakers by their actual names or roles, transforming generic labels into meaningful identifiers

TranslationAI

Automatically convert transcribed audio content from one language to another

Support(2)

Custom SLAs and SLOsPremium

Customizable Service Level Agreements and Service Level Objectives for enterprise customers

Dedicated Technical SupportPremium

Enterprise-grade technical support for production deployments

Text Analysis(3)

Filler Words DetectionAI

Identify and track filler words in transcriptions

Key PhrasesAI

Accurately identify significant words and phrases in transcription to extract pertinent concepts or highlights

Topic DetectionAI

Label the topics spoken in audio and video files using standardized IAB Taxonomy for contextual targeting

Text Processing(5)

Auto ChaptersAI

Automatically generate summaries over time for audio and video files

Auto Punctuation and CasingAI

Automatically add punctuation and proper casing to transcriptions for clearer outputs

Custom FormattingAI

Automatically standardize and format specific types of information in transcripts including dates, phone numbers, and emails

SummarizationAI

AI-powered automatic summarization of audio and video data with customizable summary types

Word-level Timestamps

Get precise timestamp information for each word in transcription

Pricing

Free

Free
  • Transcribe up to 185 hours of pre-recorded audio
  • Transcribe up to 333 hours of streaming audio
  • Up to 5 new streams per minute
  • Access to industry-leading Speech-to-Text and Audio Intelligence models
  • Developer docs and community support

Pay as you go

Starting at $0.15/hr
  • Unlimited access to Speech-to-Text, Speech Understanding, and LLM Gateway
  • Unlimited concurrent streams and pre-recorded concurrency starting at 200 files
  • Customize rate limits - scale to any workload
  • Dedicated technical support and customized SLAs and SLOs
  • BAA for HIPAA and compliance with EU Data Residency standards
  • Self-hosted deployments (On-prem, EU, VPC)

Enterprise

Custom
  • Tiered pricing options
  • Dedicated infrastructure
  • Custom model configurations
  • Customized solutions for specific needs

Cost Calculator

Pricing data not available for AssemblyAI. Check their website for current pricing.

Build vs Buy

Should you build a AssemblyAI alternative or buy the subscription? Estimate based on 38 features.

Buy AssemblyAI

Better Value
Monthly costContact Sales
3-year totalVaries
Time to deployDays

Build Your Own

Development cost$24,000
Maintenance$360/mo
3-year total$36,960
Dev time~2 months

Buying AssemblyAI saves ~$36,960 over 3 years vs building.

Estimates based on 38 features and a BuildScore of 5/5. Actual costs vary.

Integrations

21 known integrations

ChatGPT-4oClaude 3 HaikuClaude 3.5 HaikuClaude 4 OpusClaude 4 SonnetClaude 4.5 HaikuClaude 4.5 SonnetGemini 2.5 FlashGemini 2.5 Flash LiteGemini 2.5 ProGemini 3 FlashGemini 3 ProGPT 4.1GPT-5GPT-5 NanoGPT-5-MiniGPT-5.1GPT-5.2gpt-oss-120bgpt-oss-20bLiveKit SDK