RESTful API Endpoints
Clean, well-documented REST endpoints for transcription, translation, subtitle formatting, and file management. Predictable URL structure, standard HTTP methods, and JSON responses make integration straightforward.
Developer API
Subtitle Generator API - Automate Captioning at Scale
Integrate CapsAI's powerful transcription and subtitle generation directly into your application, platform, or workflow with our production-ready REST API. Full-featured SDKs for Python, Node.js, and Go make integration effortless. Webhooks notify your system when processing completes, batch endpoints handle bulk operations, and enterprise rate limits support millions of requests. Build captioning into your product without training your own models.
99.9%
API Uptime SLA
3
Official SDKs
<2s
Avg Response Time
Features
API Features & Capabilities
Webhook Notifications
Register webhook URLs to receive real-time POST notifications when transcription jobs complete, fail, or reach milestones. No polling required - your system reacts instantly to processing events.
Official SDKs (Python/Node/Go)
Production-ready SDK libraries for Python, Node.js, and Go with type definitions, error handling, retry logic, and streaming support built in. Install via pip, npm, or go get and start building in minutes.
Batch Processing Endpoints
Submit hundreds of files in a single API call with our batch endpoint. Track bulk job progress, receive completion webhooks, and download results programmatically without managing individual file states.
Authentication & Security
API key authentication with environment-scoped keys (development, staging, production). IP allowlisting, request signing, and OAuth 2.0 support for enterprise integrations with strict security requirements.
Rate Limits & Pricing Tiers
Transparent rate limits from 100 requests/minute (free) to 10,000+/minute (enterprise). Pay-per-minute pricing with volume discounts, committed-use contracts, and real-time usage dashboards.
Workflow
How to Integrate the CapsAI API
Step 1
Get Your API Key
Sign up and generate API keys from your dashboard. Create separate keys for development, staging, and production environments with independent rate limits and permissions.
Step 2
Install SDK & Submit Audio
Install our Python, Node.js, or Go SDK. Submit audio/video files via upload or public URL. The API returns a job ID for tracking the asynchronous transcription process.
Step 3
Receive Webhook or Poll Status
Get notified via webhook when transcription completes, or poll the status endpoint. The response includes full transcript, timestamps, speaker labels, and confidence scores.
Step 4
Retrieve Subtitles in Any Format
Download generated subtitles as SRT, VTT, JSON, or plain text via the results endpoint. Apply translations, styling, or custom formatting through additional API parameters.
Use Cases
API Integration Use Cases
Video Platforms & CMS
Auto-generate subtitles for every video uploaded to your platform. Trigger transcription on upload events and attach results to video metadata without manual intervention.
E-Learning & LMS Providers
Ensure every course video has accurate captions by integrating caption generation into your content pipeline. Meet accessibility compliance automatically at scale.
Media Workflows & DAM Systems
Add transcription to your digital asset management pipeline. Index video content by transcript for searchability and auto-generate metadata for content libraries.
SaaS Products & Startups
Ship captioning features in your product without building ML infrastructure. Our API handles the heavy lifting while you focus on your core product experience.
FAQ
Subtitle Generator API FAQs
What are the API rate limits?
Free tier: 100 requests/minute, 10 concurrent jobs. Pro tier: 1,000 requests/minute, 50 concurrent jobs. Enterprise: 10,000+ requests/minute with custom concurrent job limits and dedicated infrastructure.
Which programming languages have official SDKs?
We provide official SDKs for Python (pip install capsai), Node.js (npm install @capsai/sdk), and Go (go get github.com/capsai/capsai-go). Community SDKs exist for Ruby, PHP, and Java.
How does webhook delivery work?
Register a webhook URL via the API or dashboard. When transcription jobs complete or fail, we send a signed POST request to your URL with the job results. Failed deliveries retry with exponential backoff up to 24 hours.
What is the API pricing model?
Pay-per-minute of audio processed. Free tier includes 60 minutes/month. Pro starts at $0.006/minute with volume discounts. Enterprise gets custom pricing with committed-use contracts and SLA guarantees.
Is the API suitable for real-time/live transcription?
Our REST API is optimized for file-based (asynchronous) transcription. For real-time streaming transcription, use our WebSocket API endpoint which delivers partial results as speech is detected with sub-second latency.
Build captioning into your product today
Get your free API key and start generating subtitles programmatically in minutes. Official SDKs for Python, Node.js, and Go - 99.9% uptime SLA with enterprise support available.
Get API Key Free →