Authentication

The Tether API uses API keys for authentication. All requests must include your key in the Authorization header.

Generating an API key

API keys are scoped to a specific product in your Tether account. To create one:

1. Go to Settings → Products and select a product.
2. Scroll to the API section.
3. Click Generate API Key.
4. Copy the key — it will only be shown once.

Because keys are product-scoped, every request made with a key is automatically restricted to that product's data. You cannot use a key to access customers or data belonging to a different product.

Authenticating requests

Pass your API key as a Bearer token in the Authorization header of every request:

Authorization: Bearer YOUR_API_KEY

Example

import { useEffect, useState } from "react";

export function useData() {
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    fetch("https://usetether.io/api/v1/customers", {
      headers: {
        Authorization: `Bearer ${import.meta.env.VITE_TETHER_API_KEY}`,
      },
    })
      .then((res) => res.json())
      .then((json) => { setData(json); setLoading(false); });
  }, []);

  return { data, loading };
}

Request headers

Errors

If authentication fails, the API returns a 401 response:

1{
2  "error": "Unauthorized",
3  "code": "UNAUTHORIZED"
4}

Common causes:

• Missing Authorization header
• Malformed token (must be Bearer <key>, not just the key)
• Key has been revoked — generate a new one in Settings