API Reference

API Documentation

Generate QR codes with a single URL. No SDK, no library, no signup required.

Base URL:https://online-qr.com/v1/

Quick Start

The simplest way to use the API — embed the endpoint URL directly in an <img> tag. No API key, no authentication, no setup required.

HTML

<img src="https://api.online-qr.com/v1/make-qr?data=https://example.com" alt="QR Code" />

The endpoint returns a raw PNG image. Use it in any <img> tag, Markdown document, or email template — no additional code needed.

Endpoints

GET/v1/make-qr— Generate a QR code image

Returns a QR code image in the requested format. All styling options are passed as query parameters. No authentication required for public use.

Query Parameters

Parameter	Type	Required	Default	Description
`data`	string	Yes	—	URL or any text content to encode. Must be URL-encoded.
`size`	number	No	`300`	Output image size in pixels (100–2000). Applied to both dimensions.
`format`	string	No	`png`	Output format: png, webp, or svg.
`template`	string	No	—	Template slug for a pre-configured styled QR (e.g. facebook, youtube).
`dotsColor`	string	No	`#000000`	Dot color in hex. URL-encode the # as %23.
`dotsType`	string	No	`rounded`	Dot style: rounded, dots, square, extra-rounded.
`cornerSquareColor`	string	No	`#000000`	Color of the three finder (corner) squares.
`backgroundColor`	string	No	`#ffffff`	Background color in hex.
`watermark`	boolean	No	`false`	Overlay a "Powered by Online-QR" watermark (free tier).
`view`	string	No	`auto`	raw forces the image bytes, page forces the browser preview. Omit to auto-detect.

Example URL

URL

https://api.online-qr.com/v1/make-qr?data=https%3A%2F%2Fexample.com&size=400&dotsType=rounded&dotsColor=%23ff6b35&backgroundColor=%23ffffff

Opening the URL in a browser shows a small preview page with a download button instead of the bare image. Every programmatic caller — <img> tags, fetch, curl and SDKs — still receives the raw image bytes, unchanged. Append &view=raw to force the image in a browser tab.

POST/v1/json-to-qr— Generate QR with full JSON config

For advanced styling, send a JSON body with the full QR configuration. Accepts nested configuration objects for fine-grained control over dots, corners, and background.

Request Body

JSON

{
  "data": "https://example.com",
  "size": 500,
  "format": "png",
  "dotsOptions": {
    "color": "#1a1a2e",
    "type": "rounded"
  },
  "cornersSquareOptions": {
    "color": "#6c63ff",
    "type": "extra-rounded"
  },
  "backgroundOptions": {
    "color": "#ffffff"
  }
}

Response

Returns binary image data directly.

Content-Typeimage/png

Status200 OK

Authentication Required for all Redirect Endpoints

POST/v1/redirects/— Create dynamic QR redirect

Creates a managed short link (online-qr.com/r/:shortCode) that redirects to your destination URL. Enables scan tracking and lets you change the destination without reprinting the QR code.

Required Headers

`Authorization`	Bearer <token>
`Content-Type`	application/json

Request Body

JSON

{
  "destinationUrl": "https://example.com/campaign",
  "customShortCode": "summer24",
  "password": null,
  "expiresAt": null
}

Response — 201 Created

JSON

{
  "id": "clx1abc2def3",
  "shortCode": "summer24",
  "destinationUrl": "https://example.com/campaign",
  "scanCount": 0,
  "createdAt": "2026-02-28T10:00:00Z",
  "expiresAt": null,
  "isActive": true
}

GET/v1/redirects/— List all redirects

Returns a paginated list of all dynamic QR redirects for the authenticated user. Supports ?page= and ?limit= query parameters (defaults: page 1, limit 20).

GET/v1/redirects/:id/analytics— Get scan analytics

Returns aggregated scan analytics: total scans, unique visitors, device type breakdown, country distribution, browser, OS, and time-series data. Supports ?from= and ?to= ISO 8601 date range filters.

GET/v1/redirects/:id/analytics/export— Export scan data as CSV

Exports raw scan events as a downloadable CSV file. Each row contains: timestamp, ip_address, user_agent, referrer, country, city, device_type, os, browser .

Authentication

No Auth — Static QR Generation

GET /v1/make-qr and POST /v1/json-to-qr require no credentials. Subject to the free-tier rate limit of 100 requests/hour per IP.

Bearer Token — Dynamic QR & Analytics

All /v1/redirects/ endpoints require authentication. Pass your API key or session token in the Authorization header.

Sending the token

HTTP Header

Authorization: Bearer YOUR_API_KEY

Get an API key

Sign in and navigate to Settings › API Keys to create a long-lived API key for server-side integrations. New accounts receive a 14-day Pro trial automatically — no credit card required.

Code Examples

curl

curl -o qr.png \
  "https://api.online-qr.com/v1/make-qr?data=https%3A%2F%2Fexample.com"

Rate Limits

Limits apply per IP address (unauthenticated) or per account (authenticated) on a rolling one-hour window. Exceeding the limit returns 429 Too Many Requests with a Retry-After header indicating when the window resets.

Tier	Requests / Hour	Notes
Free (unauthenticated)	100 / hour	Per IP address. No account required.
Pro	1,000 / hour	Per authenticated account. 14-day trial included.
Enterprise	10,000 / hour	Contact us for custom limits and SLA agreements.

Need higher limits for a production integration? Create a Pro account (free 14-day trial) or contact us for Enterprise pricing and custom SLA.

Error Codes

All errors return a JSON body with a message field describing the problem. Image generation endpoints return the HTTP status only (no body) when the request is fundamentally malformed.

Code	Meaning	Common Cause
400	Bad Request	Missing required parameter (data), invalid value, or out-of-range size.
401	Unauthorized	Missing or invalid Authorization header on a protected endpoint.
404	Not Found	The requested redirect ID or template slug does not exist.
429	Too Many Requests	Rate limit exceeded. Check the Retry-After response header for reset time.
500	Internal Server Error	Unexpected server error. Retry with exponential backoff.

Error Response Shape

JSON

{
  "status": 400,
  "message": "Invalid parameter: 'size' must be between 100 and 2000"
}