Troubleshooting
If requests fail, run zero doctor check-connector --env-name LOOPS_TOKEN or zero doctor check-connector --url https://app.loops.so/api/v1/api-key --method GET
Core APIs
Test API Key
Verify your API key is valid:
curl -s "https://app.loops.so/api/v1/api-key" --header "Authorization: Bearer $LOOPS_TOKEN"
Create Contact
Write to /tmp/loops_request.json:
{
"email": "user@example.com",
"firstName": "Jane",
"lastName": "Doe",
"userId": "clerk_user_abc123",
"subscribed": true,
"userGroup": "free"
}
curl -s -X POST "https://app.loops.so/api/v1/contacts/create" --header "Authorization: Bearer $LOOPS_TOKEN" --header "Content-Type: application/json" -d @/tmp/loops_request.json
Docs: https://loops.so/docs/api-reference/create-contact
Update Contact
Write to /tmp/loops_request.json:
{
"email": "user@example.com",
"userGroup": "pro",
"planUpgradedAt": "2024-01-15"
}
curl -s -X PUT "https://app.loops.so/api/v1/contacts/update" --header "Authorization: Bearer $LOOPS_TOKEN" --header "Content-Type: application/json" -d @/tmp/loops_request.json
Find Contact
Find a contact by email address. Replace <email> with the actual email:
curl -s "https://app.loops.so/api/v1/contacts/find?email=<email>" --header "Authorization: Bearer $LOOPS_TOKEN"
Delete Contact
Write to /tmp/loops_request.json:
{
"email": "user@example.com"
}
curl -s -X DELETE "https://app.loops.so/api/v1/contacts/delete" --header "Authorization: Bearer $LOOPS_TOKEN" --header "Content-Type: application/json" -d @/tmp/loops_request.json
Send Event
Trigger an automated email loop by sending an event. Events map to loops configured in your Loops dashboard.
Write to /tmp/loops_request.json:
{
"email": "user@example.com",
"eventName": "signup",
"eventProperties": {
"planType": "free",
"signupSource": "landing_page"
}
}
curl -s -X POST "https://app.loops.so/api/v1/events/send" --header "Authorization: Bearer $LOOPS_TOKEN" --header "Content-Type: application/json" -d @/tmp/loops_request.json
Docs: https://loops.so/docs/api-reference/send-event
Send Transactional Email
Send a one-off email using a transactional template. Replace <transactional-id> with the ID from your Loops dashboard.
Write to /tmp/loops_request.json:
{
"transactionalId": "<transactional-id>",
"email": "user@example.com",
"dataVariables": {
"firstName": "Jane",
"resetLink": "https://app.example.com/reset?token=abc123"
}
}
curl -s -X POST "https://app.loops.so/api/v1/transactional" --header "Authorization: Bearer $LOOPS_TOKEN" --header "Content-Type: application/json" -d @/tmp/loops_request.json
Docs: https://loops.so/docs/api-reference/send-transactional-email
List Transactional Emails
curl -s "https://app.loops.so/api/v1/transactional" --header "Authorization: Bearer $LOOPS_TOKEN" | jq '[.[] | {id, name}]'
List Mailing Lists
curl -s "https://app.loops.so/api/v1/lists" --header "Authorization: Bearer $LOOPS_TOKEN" | jq '[.[] | {id, name}]'
List Contact Properties
curl -s "https://app.loops.so/api/v1/contacts/customFields" --header "Authorization: Bearer $LOOPS_TOKEN" | jq '[.[] | {key, label, type}]'
Guidelines
- Contact identity: Use
emailas the primary identifier. Optionally passuserId(e.g., Clerk user ID) to link contacts across systems. - Event names: Must exactly match the event name configured in your Loops dashboard loop trigger.
- Transactional IDs: Find the
transactionalIdin Loops under Transactional > [template] > API. - Rate limit: 10 requests per second per team. Implement exponential backoff on HTTP 429.
- Field length: Maximum 500 characters per field value.
- No CORS: All requests must be server-side — never expose the API key to the browser.