AssemblyAI vs Castmagic
AssemblyAI and Castmagic are both audio AI tools, tracked here on price, platforms, integrations, and capabilities. Every figure below is read from the vendor's own pages and dated. No score and no winner: the facts do the picking.
AssemblyAI
Voice AI infrastructure for builders
AssemblyAI delivers production-ready Voice AI models, including pre-recorded and real-time streaming speech-to-text, speaker diarization, and voice agent APIs. It provides advanced models like Universal-3.5 Pro, supporting multiple languages and specialized medical transcription modes.
Castmagic
AI content platform for audio and video repurposing
Castmagic is an AI content platform that converts audio and video recordings into transcripts, show notes, newsletters, and social media posts. The platform supports over 60 languages and integrates with tools like Zoom, Google Drive, and Zapier. Content teams and creators collaborate in shared workspaces to draft and publish assets in their brand voice.
At a glance
Capability tags are factual labels we assign when a tool is added; they describe what a tool does, not how well it does it.
Checked against the vendors. Written from each vendor's own site and last re-checked there: AssemblyAI on July 31, 2026 · Castmagic on July 29, 2026. Vendors change pricing and features without notice, so confirm anything that decides your purchase on the vendor's page.
Also in audio
A tool we have an affiliate relationship with. It is not part of the comparison above and we are not calling it the better pick.
- Recording and summarizing meetings without sending a bot into the call
- Pulling action items out of a call instead of writing notes during it
- Enhancing clarity in online meetings
Key features
AssemblyAI
- Pre-recorded and real-time streaming speech-to-text transcription
- Speaker diarization to segment utterances by speaker
- LLM-powered Speech Understanding and LLM Gateway
- Custom keyterms prompting and Medical Mode for specialized terminology
Castmagic
- Automated speaker-labeled transcription in over 60 languages
- AI asset drafting for show notes, newsletters, blogs, and social posts
- Custom brand voice parameters and editable content templates
- Team workspaces with user permissions and approval workflows
- Semantic library search to locate quotes and key moments
What each one does well
AssemblyAI
- ✓ Building real-time voice agents
- ✓ Transcribing pre-recorded audio files with high accuracy
- ✓ Performing call analytics and medical transcription
Castmagic
- ✓ Repurposing podcast and video recordings into social posts, newsletters, and blogs
- ✓ Content teams and agencies managing multi-brand client media pipelines
- ✓ Transcribing and summarizing meetings, webinars, and sales calls
People also ask
Which is cheaper, AssemblyAI or Castmagic?
AssemblyAI starts at $0.02 usage-based and Castmagic starts at $19/mo. The two are billed over different periods, so we do not rank them on price.
Does AssemblyAI or Castmagic have a free plan?
AssemblyAI publishes no free plan, and Castmagic publishes no free plan.
What is the difference between AssemblyAI and Castmagic?
Both are tracked for speech-to-text, transcription, speaker-identification. Of the capabilities they do not share, only AssemblyAI is tracked for developer-api, and only Castmagic is tracked for summarization, brand-voice, marketing-content.
How much do AssemblyAI and Castmagic cost?
AssemblyAI: from $0.02 usage-based. Castmagic: from $19/mo.
Answers are generated from the tracked plans and capability tags shown above, so they move when the vendors' pages do.
Full fact sheets, FAQs, and discussion links: AssemblyAI · Castmagic · all audio tools