Create Link

Create a new short link with platform-specific routing, attribution tracking, and UTM parameters.

Core vs Cloud

Core and Cloud accept different fields. Core requires userId and originalUrl. Cloud requires either templateId or templateSlug, derives userId from your API key, and does not accept originalUrl — its web destination is webFallbackUrl. See examples for both below.

Endpoint

POST /api/links

Authentication

• Core (Self-Hosted): Include userId in the request body. See Authentication.
• Cloud: Requires a valid API key in the Authorization header. See Authentication.

---

Request Body

Core Fields

Field	Type	Required	Description
userId	string (UUID)	Yes	User ID for link ownership
originalUrl	string (URL)	Yes	Destination URL (fallback)
templateId	string (UUID)	No	Template to use for default values
customCode	string	No	Custom short code
title	string	No	Internal title
description	string	No	Internal description
iosAppStoreUrl	string (URL)	No	iOS App Store URL
androidAppStoreUrl	string (URL)	No	Android Play Store URL
webFallbackUrl	string (URL)	No	Destination for web users
appScheme	string	No	Custom URL scheme, without :// (e.g. myapp)
iosUniversalLink	string (URL)	No	iOS Universal Link URL
androidAppLink	string (URL)	No	Android App Link URL
deepLinkPath	string	No	Deep link path within the app
deepLinkParameters	object	No	Key-value pairs passed to the app
attributionWindowHours	number	No	Attribution window (1-2160 hours). Default: 168 (7 days)
utmParameters	object	No	UTM parameters to append
targetingRules	object	No	Geographic/language/device targeting
ogTitle	string	No	Open Graph title for social previews
ogDescription	string	No	Open Graph description
ogImageUrl	string (URL)	No	Open Graph image URL
ogType	string	No	Open Graph type (e.g. website)
expiresAt	string (ISO 8601)	No	Expiration timestamp

Cloud Fields

Field	Type	Required	Description
templateId	string (UUID)	See note	Template to use for default values
templateSlug	string	See note	Template slug, as an alternative to templateId
title	string	No	Internal title for organization
description	string	No	Internal description
iosAppStoreUrl	string (URL)	No	Destination for iOS users
androidAppStoreUrl	string (URL)	No	Destination for Android users
webFallbackUrl	string (URL)	No	Destination for web users (http/https only)
appScheme	string	No	Custom URL scheme, lowercase, without :// (e.g. myapp)
iosUniversalLink	string (URL)	No	iOS Universal Link URL
androidAppLink	string (URL)	No	Android App Link URL
deepLinkPath	string	No	Deep link path within the app
customSchemeUrl	string	No	Full custom-scheme destination (e.g. myapp://product/123)
deepLinkParameters	object	No	Key-value pairs passed to the app
customCode	string	No	Custom short code
projectId	string (UUID) | null	No	Project to assign the link to. null clears the assignment
domainId	string (UUID) | null	No	Custom domain to issue the link on. null uses the workspace default
utmParameters	object	No	UTM parameters to append
targetingRules	object	No	Geographic/language/device targeting
attributionWindowHours	number	No	Install attribution window, 1-2160 hours
eventAttributionWindowHours	number	No	In-app event attribution window, 1-2160 hours
expiresAt	string (ISO 8601)	No	Expiration timestamp
appendClickId	boolean	No	Append ?lf_click=<id> to web destinations. Defaults to true on Cloud
ogTitle	string (max 255)	No	Open Graph title for this link's share preview
ogDescription	string (max 500)	No	Open Graph description
ogImageUrl	string (URL)	No	Open Graph image URL, http(s) only
ogType	string	No	Open Graph type. Defaults to website

Per-link previews for user-shared content

The og* fields override the workspace and template share cards for that one link, so a link a user creates to share a specific item can unfurl with that item's own title and image. Leave them unset and the link uses the card configured in the dashboard. See Social Share Preview for the full resolution order.

Cloud requires a template

Every Cloud link belongs to a template, but you may identify it with either templateId or templateSlug — one of the two is required. Templates define default settings for your links. See Link Templates.

Unknown fields are silently ignored

The request schema discards field names it does not recognise instead of rejecting them, so a misspelled or non-existent field produces a successful response with that value dropped. If a link is created without a destination you set, check the field name against this table first.

In particular, Cloud does not accept originalUrl, iosUrl, or androidUrl. Those are Core field names — the Cloud equivalents are webFallbackUrl, iosAppStoreUrl, and androidAppStoreUrl.

UTM Parameters Object

{
  source?: string;    // Traffic source (e.g., "instagram")
  medium?: string;    // Marketing medium (e.g., "social")
  campaign?: string;  // Campaign name (e.g., "spring-sale-2024")
  term?: string;      // Paid keywords (e.g., "wireless-headphones")
  content?: string;   // Content variant (e.g., "carousel-ad-1")
}

Targeting Rules Object

{
  countries?: string[];   // ISO 3166-1 alpha-2 codes (e.g., ["US", "CA", "GB"])
  languages?: string[];   // ISO 639-1 codes (e.g., ["en", "es", "fr"])
  devices?: string[];   // ["ios", "android", "web"]
}

---

Response

Success Response

Status Code: 201 Created

Core response:

{
  "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "short_code": "abc123",
  "user_id": "550e8400-e29b-41d4-a716-446655440000",
  "original_url": "https://example.com/products/wireless-headphones",
  "title": "Wireless Headphones - Spring Sale",
  "description": "Q2 2024 Instagram campaign",
  "ios_app_store_url": "https://apps.apple.com/app/your-store/id123456789",
  "android_app_store_url": "https://play.google.com/store/apps/details?id=com.yourstore",
  "web_fallback_url": "https://example.com/products/wireless-headphones?platform=web",
  "attribution_window_hours": 168,
  "utm_parameters": {
    "source": "instagram",
    "medium": "social",
    "campaign": "spring-sale-2024"
  },
  "targeting_rules": {
    "countries": ["US", "CA", "GB"],
    "languages": ["en"],
    "devices": ["ios", "android"]
  },
  "is_active": true,
  "expires_at": null,
  "created_at": "2024-01-20T15:30:00.000Z",
  "updated_at": "2024-01-20T15:30:00.000Z"
}

Cloud response includes additional fields:

{
  "id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "short_code": "abc123",
  "short_url": "https://lnk.forty.com/abc123",
  "user_id": "user_123",
  "organization_id": "org_456",
  "project_id": null,
  "template_id": "template_789",
  "original_url": null,
  "title": "Wireless Headphones - Spring Sale",
  "ios_app_store_url": "https://apps.apple.com/app/your-store/id123456789",
  "android_app_store_url": "https://play.google.com/store/apps/details?id=com.yourstore",
  "web_fallback_url": "https://example.com/products/wireless-headphones?platform=web",
  "attribution_window_hours": 168,
  "utm_parameters": {
    "source": "instagram",
    "medium": "social",
    "campaign": "spring-sale-2024"
  },
  "is_active": true,
  "expires_at": null,
  "created_at": "2024-01-20T15:30:00.000Z",
  "updated_at": "2024-01-20T15:30:00.000Z"
}

Error Responses

400 Bad Request - Invalid URL

{
  "error": "Bad Request",
  "message": "Invalid URL format",
  "statusCode": 400,
  "validation": {
    "originalUrl": "Must be a valid URL"
  }
}

400 Bad Request - Invalid Attribution Window

{
  "error": "Bad Request",
  "message": "Attribution window must be between 1 and 2160 hours",
  "statusCode": 400,
  "validation": {
    "attributionWindowHours": "Attribution window must be at least 1 hour"
  }
}

409 Conflict - Custom Code Already Exists

{
  "error": "Conflict",
  "message": "Short code 'spring-sale' is already in use",
  "statusCode": 409
}

401 Unauthorized (Cloud)

{
  "error": "Unauthorized",
  "message": "Missing or invalid API key",
  "statusCode": 401
}

404 Not Found - Template Not Found (Cloud)

{
  "error": "Not Found",
  "message": "Template not found",
  "statusCode": 404
}

---

Examples

Core - Basic Link Creation

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123"
  }'

Core - With Platform-Specific URLs

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123",
    "title": "Product 123 Campaign",
    "iosAppStoreUrl": "https://apps.apple.com/app/your-store/id123456789",
    "androidAppStoreUrl": "https://play.google.com/store/apps/details?id=com.yourstore",
    "deepLinkPath": "/product/123"
  }'

Core - With Deep Linking

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123",
    "appScheme": "myapp://",
    "iosUniversalLink": "https://myapp.com/product/123",
    "androidAppLink": "https://myapp.com/product/123",
    "deepLinkPath": "/product/123",
    "deepLinkParameters": {
      "productId": "123",
      "source": "campaign"
    }
  }'

Cloud - Basic Link Creation

curl -X POST https://api.linkforty.com/api/links \
  -H "Authorization: Bearer dl_a1b2c3d4e5f6a7b8" \
  -H "Content-Type: application/json" \
  -d '{
    "templateId": "550e8400-e29b-41d4-a716-446655440000",
    "webFallbackUrl": "https://example.com/product/123"
  }'

Cloud - With Platform-Specific URLs

curl -X POST https://api.linkforty.com/api/links \
  -H "Authorization: Bearer dl_a1b2c3d4e5f6a7b8" \
  -H "Content-Type: application/json" \
  -d '{
    "templateId": "550e8400-e29b-41d4-a716-446655440000",
    "webFallbackUrl": "https://example.com/product/123",
    "title": "Product 123 Campaign",
    "iosAppStoreUrl": "https://apps.apple.com/app/your-store/id123456789",
    "androidAppStoreUrl": "https://play.google.com/store/apps/details?id=com.yourstore"
  }'

With UTM Parameters

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123",
    "utmParameters": {
      "source": "facebook",
      "medium": "cpc",
      "campaign": "summer-2024",
      "term": "wireless-headphones",
      "content": "image-ad-1"
    }
  }'

With Attribution Window

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123",
    "attributionWindowHours": 336
  }'

Attribution Window: 336 hours = 14 days

With Targeting Rules

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/product/123",
    "targetingRules": {
      "countries": ["US", "CA"],
      "languages": ["en"],
      "devices": ["ios", "android"]
    }
  }'

Behavior: Only users in US/Canada, with English language settings, on mobile devices will be redirected. Others see default URL.

With Expiration

curl -X POST https://your-domain.com/api/links \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "550e8400-e29b-41d4-a716-446655440000",
    "originalUrl": "https://example.com/flash-sale",
    "title": "24-Hour Flash Sale",
    "expiresAt": "2024-12-31T23:59:59Z"
  }'

---

Use Cases

E-commerce Product Link

{
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "originalUrl": "https://shop.example.com/products/wireless-headphones",
  "title": "Wireless Headphones Product Page",
  "iosAppStoreUrl": "https://apps.apple.com/app/shop-app/id123",
  "androidAppStoreUrl": "https://play.google.com/store/apps/details?id=com.shop",
  "deepLinkPath": "/products/wireless-headphones",
  "attributionWindowHours": 168,
  "utmParameters": {
    "source": "instagram",
    "medium": "social",
    "campaign": "product-launch",
    "content": "product-123"
  }
}

User Flow:

1. User clicks link on Instagram
2. Mobile user redirected to App Store/Google Play
3. User installs app
4. App opens and navigates to wireless headphones product page
5. Install attributed to Instagram campaign

Referral Link

{
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "originalUrl": "https://example.com/referral/john-doe",
  "attributionWindowHours": 2160,
  "utmParameters": {
    "source": "referral",
    "medium": "friend",
    "campaign": "refer-a-friend",
    "content": "john-doe"
  }
}

Event Promotion

{
  "userId": "550e8400-e29b-41d4-a716-446655440000",
  "originalUrl": "https://example.com/events/summer-concert",
  "attributionWindowHours": 720,
  "expiresAt": "2024-07-31T23:59:59Z",
  "utmParameters": {
    "source": "facebook",
    "medium": "event",
    "campaign": "summer-concert-2024"
  }
}

Expires: July 31, 2024 (after event ends)

---

Best Practices

1. Always Provide Platform-Specific URLs

Bad:

{
  "originalUrl": "https://example.com/product"
}

Good (Core):

{
  "originalUrl": "https://example.com/product",
  "iosAppStoreUrl": "https://apps.apple.com/app/id123",
  "androidAppStoreUrl": "https://play.google.com/store/apps/details?id=com.app"
}

Good (Cloud):

{
  "webFallbackUrl": "https://example.com/product",
  "iosAppStoreUrl": "https://apps.apple.com/app/id123",
  "androidAppStoreUrl": "https://play.google.com/store/apps/details?id=com.app"
}

Improves attribution accuracy by 3-5x.

2. Use Descriptive Titles

Bad:

{
  "title": "Link 1"
}

Good:

{
  "title": "Instagram Story - Spring Sale - Wireless Headphones"
}

Makes links easier to find and manage.

3. Set Attribution Window Based on Campaign

Campaign Type	Window
Flash sale	24-72 hours
Product launch	7-14 days
Referral program	30-90 days

4. Include UTM Parameters

Always track campaign source:

{
  "utmParameters": {
    "source": "instagram",
    "medium": "social",
    "campaign": "spring-2024"
  }
}

---

Rate Limiting

• Core: Rate limiting disabled by default (configurable via environment variables)
• Cloud: 100 requests/minute per API key

See Rate Limits for details.

Related Endpoints

• Get Link - Retrieve link details
• Update Link - Modify existing link
• Delete Link - Remove link
• Bulk Operations - Create multiple links at once
• Link Analytics - View link performance

Guides

• Creating Links - Complete guide with examples
• Attribution Windows - Choosing the right window
• Link Templates - Using templates for defaults (Cloud)
• UTM Parameters - Campaign tracking best practices