Comparison
Subtitles King vs AssemblyAI
AssemblyAI is great for enterprise. Subtitles King is great for shipping fast.
TL;DR
At a glance.
| Feature | Subtitles King | AssemblyAI |
|---|---|---|
| Free tier | ✓ 100 MB videos | Free credit only |
| Cost (paid) | Pro waitlist | ~$0.37/hr |
| MCP server | ✓ hosted + self-host | ✗ |
| Self-host option | ✓ open source | ✗ |
| Burned-in subtitles | ✓ one call | Build it yourself |
| Real-time streaming | ✗ | ✓ |
| Speaker diarization | ✗ | ✓ |
| Lines to integrate | ~3 | ~25 |
When AssemblyAI wins
- Real-time streaming transcription with low latency.
- Speaker diarization, sentiment analysis, content moderation.
- Mature SDKs in many languages.
- Enterprise features and compliance certifications.
When Subtitles King wins
- Free tier handles real workloads — no credit card required.
- MCP-native: AI agents can use it directly without SDK code.
- Open source — self-host for full control.
- Returns burned-in subtitles, not just a transcript.
- ~3 lines of HTTP to integrate vs ~25 with their SDK.
Code
Integration, side by side.
# Subtitles King: 3 lines
curl -X POST https://brains.subtitlesking.com/presign \
-H "X-API-KEY: $KEY" -d '{"filename":"clip.mp4"}'
curl -X POST "$URL" -F "file=@clip.mp4"
curl -X POST https://brains.subtitlesking.com/queue -d '{"authToken":"$T"}'# AssemblyAI: ~25 lines (and you still need to burn the subtitles)
import assemblyai as aai
aai.settings.api_key = "your_key"
transcriber = aai.Transcriber()
transcript = transcriber.transcribe("clip.mp4")
srt = transcript.export_subtitles_srt()
# Now use ffmpeg to burn them in yourself...
import subprocess
subprocess.run([
"ffmpeg", "-i", "clip.mp4",
"-vf", f"subtitles={srt_file}",
"out.mp4"
])FAQ
Common questions.
Is Subtitles King a drop-in replacement for AssemblyAI?+
Not exactly — AssemblyAI does real-time streaming and speaker diarization, which we don't. For batch video subtitling, yes. We're cheaper, simpler, and we burn the subtitles in for you.
How does the cost actually compare?+
AssemblyAI is roughly $0.37/hour of audio. Our free tier is $0 for videos up to 100 MB; Pro pricing is on the waitlist but is being designed to be substantially cheaper than per-hour pricing for most batch workloads.
Can I use AssemblyAI through Subtitles King?+
No — we use OpenAI Whisper internally, not AssemblyAI. Different transcription engines have different strengths. If you need AssemblyAI-specific features like real-time, use them directly.
What if I need self-hosting?+
AssemblyAI is hosted-only. Our MCP binary and upload server are open source — you can run the entire stack on your own hardware.