AssemblyAI vs WhisperAPI

AssemblyAI

Audio

WhisperAPI

Audio

Tagline

AssemblyAI

Speech-to-text API with diarisation, summarisation, and topic detection.

WhisperAPI

Hosted OpenAI Whisper transcription with a pay-as-you-go API and drop-in web dashboard.

Pricing

AssemblyAI

Freemium· Pre-recorded Speech-to-Text API: $0.21 /hr · Universal-2: $0.15 /hr · Realtime Speech-to-Text API: $0.45 /hr · Universal-Streaming: $0.15 /hr · Universal-Streaming Multilingual: $0.15 /hr

WhisperAPI

Paid· 20 API Credits: $5 · 100 API Credits: $20 · 200 API Credits: $30 · Custom: $100.00

Lowest paid tier

AssemblyAI

$0.15 /hr · Universal-2

captured 2026-08-11

WhisperAPI

$5 · 20 API Credits

captured 2026-08-09

API

AssemblyAI

Not listed

WhisperAPI

Yes

Platforms

AssemblyAI

web

WhisperAPI

api

Company

AssemblyAI

AssemblyAI

WhisperAPI

—

Model used

AssemblyAI

Universal / Slam-1

WhisperAPI

OpenAI Whisper

Best for

AssemblyAI

Pick AssemblyAI when you need accurate streaming/batch ASR plus diarisation + summarisation without engineering it yourself.

WhisperAPI

Pick WhisperAPI if you need a no-fuss, pay-per-use Whisper endpoint for transcribing files without managing GPUs or juggling OpenAI keys.

Not for

AssemblyAI

Skip it at extreme volume — Whisper self-hosted is cheaper if engineering capacity is available.

WhisperAPI

Skip it if you need speaker diarization, real-time streaming captions, or you're already comfortable self-hosting whisper.cpp or faster-whisper.

Editorial score

AssemblyAI

8.7 / 10

WhisperAPI

6.9 / 10

Use cases

AssemblyAI

transcriptiondiarisationpodcast indexing

WhisperAPI

audio-transcriptionvideo-subtitlesmultilingual-transcriptionpodcast-to-text

Pros

AssemblyAI

• High accuracy
• Strong streaming API
• Lots of post-processing features
• Excellent SDKs and docs

WhisperAPI

• Hosted Whisper with no GPU or OpenAI key required
• Generous 10GB file size and 98+ language coverage
• Credits never expire and no monthly minimums
• Outputs JSON, VTT, DOCX, PDF out of the box

Cons

AssemblyAI

• More expensive than Whisper for high volume
• Latency varies

WhisperAPI

• More expensive than self-hosting open-source Whisper
• No advertised diarization or real-time streaming
• Thin product surface - essentially a Whisper wrapper

Website

AssemblyAI

www.assemblyai.com

WhisperAPI

whisper-api.com

Editorial score: rule-based, 0–10, from AI-assisted profile inputs (see /methodology) — not a user rating; “—” means unscored. “Not listed” means we have no record of it, not that it is absent. GitHub figures and prices carry the date they were checked or captured; prices are shown as published, unconverted.