Modern URL shortening with QR codes and detailed analytics

URL shortener, QR code generator, and link analytics API. Create short links, generate QR codes, and track click analytics.

Jo4 - URL Shortener & Analytics API

Jo4 is a modern URL shortening service with QR code generation and detailed link analytics.

Authentication

All protected endpoints require an API key. Set your API key as an environment variable:

export JO4_API_KEY="your-api-key"

Get your API key from: https://jo4.io/api-keys

API Base URL

https://jo4-api.jo4.io/api/v1

Endpoints

Create Short URL (Authenticated)

curl -X POST "https://jo4-api.jo4.io/api/v1/protected/url" \
  -H "X-API-Key: $JO4_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "longUrl": "https://example.com/very-long-url",
    "title": "My Link"
  }'

Request Body:

• longUrl (required) - The destination URL (max 2048 chars)
• title (optional) - Link title (max 200 chars)
• description (optional) - Link description (max 500 chars)
• shortUrl (optional) - Custom alias (max 16 chars, alphanumeric/hyphen/underscore)
• expirationTime (optional) - Unix timestamp for link expiration
• passwordProtected (optional) - Boolean to enable password protection
• password (optional) - Password if protected (4-128 chars)

UTM Parameters:

• utmSource, utmMedium, utmCampaign, utmTerm, utmContent

Response:

{
  "response": {
    "id": 123,
    "slug": "abc123",
    "shortUrl": "abc123",
    "fullShortUrl": "https://jo4.io/a/abc123",
    "longUrl": "https://example.com/very-long-url",
    "title": "My Link",
    "qrCodeUrl": "https://jo4.io/qr/abc123"
  }
}

Create Anonymous Short URL (No Auth Required)

curl -X POST "https://jo4-api.jo4.io/api/v1/public/url" \
  -H "Content-Type: application/json" \
  -d '{"longUrl": "https://example.com"}'

Limited features, no analytics access.

Get URL Details

curl -X GET "https://jo4-api.jo4.io/api/v1/protected/url/{slug}" \
  -H "X-API-Key: $JO4_API_KEY"

Get URL Analytics

curl -X GET "https://jo4-api.jo4.io/api/v1/protected/url/{slug}/stats" \
  -H "X-API-Key: $JO4_API_KEY"

Response includes:

• Total clicks
• Clicks by date
• Geographic distribution
• Device/browser breakdown
• Referrer sources

List My URLs

curl -X GET "https://jo4-api.jo4.io/api/v1/protected/url/myurls?page=0&size=20" \
  -H "X-API-Key: $JO4_API_KEY"

Update URL

curl -X PUT "https://jo4-api.jo4.io/api/v1/protected/url/{id}" \
  -H "X-API-Key: $JO4_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "Updated Title",
    "longUrl": "https://new-destination.com"
  }'

Delete URL

curl -X DELETE "https://jo4-api.jo4.io/api/v1/protected/url/{id}" \
  -H "X-API-Key: $JO4_API_KEY"

QR Codes

Every short URL automatically gets a QR code at:

https://jo4.io/qr/{shortUrl}

Rate Limits

Rate limits vary by plan:

• Free: 60 requests/minute
• Pro: Up to 10,000 requests/minute
• Anonymous (public endpoints): 10 requests/minute

API Documentation

Full OpenAPI/Swagger documentation: https://jo4-api.jo4.io/swagger-ui/index.html

Common Use Cases

1. Shorten a URL for sharing

curl -X POST "https://jo4-api.jo4.io/api/v1/protected/url" \
  -H "X-API-Key: $JO4_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"longUrl": "https://example.com/article", "title": "Article"}'

2. Create campaign tracking link

curl -X POST "https://jo4-api.jo4.io/api/v1/protected/url" \
  -H "X-API-Key: $JO4_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "longUrl": "https://mysite.com/landing",
    "title": "Q1 Campaign",
    "utmSource": "twitter",
    "utmMedium": "social",
    "utmCampaign": "q1-2026"
  }'

3. Create expiring link

curl -X POST "https://jo4-api.jo4.io/api/v1/protected/url" \
  -H "X-API-Key: $JO4_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "longUrl": "https://mysite.com/promo",
    "title": "Limited Offer",
    "expirationTime": 1738454400
  }'

Error Codes

Code	Meaning
400	Bad request - invalid parameters
401	Unauthorized - missing or invalid API key
403	Forbidden - insufficient permissions
404	Not found - URL doesn't exist
429	Rate limit exceeded