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Integrate our tools directly into your apps, scripts, and workflows. Simple REST endpoints, JSON responses, zero dependencies.
Full API coming soon
12 lightweight endpoints are live now. Image processing, PDF tools, video conversion, and AI APIs are coming soon. Join the waitlist to get early access.
QR codes, hashing, passwords, JSON, colors, UUIDs, and more.
Simple Bearer token authentication. Get a key instantly.
Image, PDF, video, audio, and AI processing endpoints.
All API requests require an API key. Pass it in the Authorization header or as a query parameter.
Header (recommended)
Authorization: Bearer ot4f_test_YOUR_KEYQuery parameter
GET /api/v1/uuid?count=5&api_key=ot4f_test_YOUR_KEYGet your API key — Sign up for a Pro account to receive your API key with 10,000 calls/month included.
API pricing is separate from the Pro subscription. These plans are for developers building apps with our API.
| Plan | Price | Calls / month | Status |
|---|---|---|---|
| Free | $0 | 100 | Available Now |
| Dev | $19/mo | 10,000 | Coming Soon |
| Business | $99/mo | 100,000 | Coming Soon |
| Enterprise | Custom | Unlimited | Coming Soon |
Note: The Free tier (100 calls/month, lightweight endpoints only) is available now. Paid API plans will launch alongside the full image/PDF/video API. Join the waitlist for early access.
All errors return a JSON object with an error field and the appropriate HTTP status code.
// Error response format
{ "error": "Description of what went wrong" }200Success400Bad request — missing or invalid parameters401Unauthorized — missing or invalid API key429Rate limit exceeded500Server errorThese lightweight endpoints are live and ready to use. No file uploads required — pure JSON in, JSON out.
Generate a QR code as SVG.
| Name | Type | Required | Description |
|---|---|---|---|
| data | string | Yes | The text or URL to encode |
| fgColor | string | No | Foreground color (default: #000000) |
| bgColor | string | No | Background color (default: #FFFFFF) |
| errorCorrection | L|M|Q|H | No | Error correction level (default: M) |
curl -X POST "https://onlinetools4free.com/api/v1/qr-code" \
-H "Authorization: Bearer ot4f_test_YOUR_KEY" \
-H "Content-Type: application/json" \
-d '{"data":"https://example.com","fgColor":"#000000","bgColor":"#FFFFFF","errorCorrection":"M"}'{ "svg": "<svg ...>...</svg>", "modules": 25 }These endpoints are under active development. They require server-side processing for file uploads (images, PDFs, video, audio). Join the waitlist to get notified when they launch.
Get notified when image, PDF, video processing, and AI APIs launch. Early waitlist members get priority access and discounted pricing.
12 endpoints are live right now. Get your API key and start making requests in under a minute.