Skip to main content
Lantern exposes form endpoints through Shopify’s App Proxy at /a/lantern. Use these endpoints to render dynamic forms on the storefront and submit responses that update customer data.

​
Get a form

  • Method: GET
  • Path: /a/lantern/form/{handle}
  • Path params: handle (string, required) — unique form handle
Returns the form structure so you can render inputs on the storefront. 
{
  "id": "form-id-123",
  "handle": "newsletter-signup",
  "name": "Newsletter Signup",
  "fields": [
    {
      "handle": "profile:email",
      "label": "Email Address",
      "required": true,
      "valueType": "String",
      "fieldType": "Text",
      "inputType": "TextInput",
      "placeholder": "Enter your email"
    }
  ]
}
Form fields may include choices for select/radio inputs and propertyDefinition when the field maps to a Lantern property.

​
Submit a form

  • Method: POST
  • Path: /a/lantern/form/{handle}
  • Path params: handle (string, required)
  • Query params: locale (string, optional) — overrides the browser locale
  • Body: JSON object where keys are field handles and values are the submitted data
Example request body: 
{
  "profile:first-name": "Alex",
  "profile:last-name": "Rivera",
  "profile:email": "alex@example.com",
  "profile:birth-date": "1990-01-01",
  "attribute:favorite-color": "blue",
  "custom-field": "extra value"
}
Use profile: prefixes to update Shopify customer properties and attribute: prefixes for custom Lantern attributes. Other keys are stored as submitted.
Successful responses return the submitted data and an event id you can use for auditing: 
{
  "success": true,
  "eventId": "evt_12345abcde",
  "data": {
    "profile:first-name": "Alex",
    "profile:email": "alex@example.com"
  }
}

​
Errors

  • 400 Bad Request for validation issues
  • 401 Unauthorized if the Shopify App Proxy signature is missing or invalid
  • 422 Unprocessable Entity for invalid submissions (for example, required fields missing)