Developer REST API Platform

Automate PDF & Image Workflows with One Simple API

Integrate conversion, compression, signing, merging, and extraction into your web or mobile app. Start with our generous free tier, scale to millions of documents effortlessly.

Get Free API Key Interactive API Documentation →

Your Live API Key

Bearer token for REST requests

Enterprise Reliability

Built for Production Scale

Sub-second document conversion latency
Automatic PDF repair & broken xref reconstruction
CORS enabled for direct browser-to-API calls
Zero retention guarantee (ephemeral RAM processing)

Quickstart Example

curl -X POST https://heyhlo.com/api/v1/compress \
  -H "Authorization: Bearer hlo_live_YOUR_API_KEY_HERE" \
  -H "Content-Type: application/json" \
  -d '{"file": "<BASE64_PDF_STRING>", "quality": "recommended"}'

POST https://heyhlo.com/api/v1/compressOpen API Playground

POST/api/v1/compress

Adaptive lossy and lossless stream compression with configurable quality levels.

POST/api/v1/convert

Convert between PDF, Word DOCX, Excel XLSX, JPG, PNG, and WebP in both directions.

POST/api/v1/merge

Concatenate unlimited PDFs into a unified file while maintaining bookmarks and structure.

POST/api/v1/split

Extract custom page ranges (e.g. '1-3, 5') into separate lightweight PDF files.

Subscription Tiers

Transparent Pricing for Developers & Companies

Upgrade your API key quota instantly. Cancel or switch plans at any time with zero penalty.

Starter Developer

$19/month

1,000 requests/mo

100 MB per file

1,000 API requests every month
High-speed cloud conversion pipeline
All 70+ PDF & Image tools included
Up to 100MB file size limit
Full REST API access (cURL, Python, Node, PHP)
Standard email & Discord support

Pro Growth

$49/month

5,000 requests/mo

250 MB per file

5,000 API requests every month
Priority processing queue (<500ms latency)
Batch conversion & multi-PDF merge up to 50 files
Up to 250MB file size limit
Webhook callback notifications on job completion
Dedicated API integration engineer support

Enterprise Scale

$149/month

25,000 requests/mo

500 MB per file

25,000 API requests every month
Custom SLA 99.99% uptime guarantee
Dedicated private server instances
Up to 500MB file size limit
Custom fonts & OCR document parsing
Direct WhatsApp & Slack hotline

Loading HeyHlo Studio...

curl -X POST https://heyhlo.com/api/v1/compress \ -H "Authorization: Bearer hlo_live_YOUR_API_KEY_HERE" \ -H "Content-Type: application/json" \ -d '{"file": "<BASE64_PDF_STRING>", "quality": "recommended"}'