Authentication
All requests use your FetchLayer API key as a Bearer token. There is no account to create on Linktree or any other link-page service, and no OAuth flow — this reads pages that are public to anyone with the address.
Sending requests
bash
curl -X POST https://api.fetchlayer.dev/link-in-bio/profile \
-H "Authorization: Bearer ss-your-key" \
-H "Content-Type: application/json" \
-d '{"profile":"https://linktr.ee/spotify"}'Keep your key secret
Only use API keys in server-side code and rotate a key immediately if it is exposed.
Every route is a POST
Every route takes a JSON body over POST, so nothing travels in a URL. Unrecognised body fields are rejected with a 400 naming the field — sending url where the route wants profile returns profile: Invalid input: expected string, received undefined; Unrecognized key: "url" rather than quietly reading nothing.
Authentication errors
A missing or invalid key returns HTTP 401. A key scoped to other platforms returns HTTP 403.
json
{
"error": "Invalid API key"
}