Authentication

All requests to the Linq Partner API require authentication via a bearer token in the Authorization header. The official SDKs handle authentication automatically.

Bearer token authentication

Include your API token in every request:

Authorization: Bearer YOUR_TOKEN

Your token determines:

• Which phone numbers you can send from
• Which data you can access (chats, messages, attachments)
• Your rate limits and daily message quotas

Getting your token

Contact your Linq representative to provision a bearer token for your organization. Each token is scoped to a specific set of phone numbers and permissions.

Making authenticated requests

curl https://api.linqapp.com/api/partner/v3/chats \
  -H "Authorization: Bearer $LINQ_API_KEY" \
  -H "Content-Type: application/json"

import LinqAPIV3 from '@linqapp/sdk';

const client = new LinqAPIV3({
  apiKey: process.env.LINQ_API_KEY, // reads LINQ_API_V3_API_KEY by default
});

import os
from linq import LinqAPIV3

client = LinqAPIV3(api_key=os.environ["LINQ_API_KEY"])

Token security best practices

• Use environment variables — Never hardcode tokens in source code
• Never commit tokens — Add .env to .gitignore
• Rotate regularly — Request new tokens periodically from your Linq representative
• Limit access — Only share tokens with team members who need them
• Use separate tokens — Use different tokens for development and production

Error responses

Status	Code	Description
401	2004	Missing or invalid bearer token. Check that your Authorization header is correctly formatted.
403	2005	Valid token but insufficient permissions for this resource.
403	2006	You cannot send from this phone number. Verify the phone is assigned to your account.
429	1007	Rate limit exceeded. See Rate Limits.

See Error Codes for the complete error reference and the API Reference for endpoint specifications.