Authentication

All API requests (except the registration endpoints) require a Bearer token in the Authorization header.

Header Format

Authorization: Bearer mfx_test_abc123...

Key Types

Prefix	Environment	Traffic
`mfx_test_`	Sandbox	Routed to sandbox. No real faxes sent.
`mfx_live_`	Live	Routed to production. Real faxes delivered.

The key prefix determines routing automatically. There is no separate sandbox URL or environment toggle. See Environments for how isolation works.

Getting Your First Key

# Step 1: Start registration (sends a 6-digit code to your email)
curl -X POST https://api.mintfax.com/v1/account/register \
  -H "Content-Type: application/json" \
  -d '{"name": "My App", "email": "dev@example.com"}'

# Step 2: Verify the code from your email
curl -X POST https://api.mintfax.com/v1/account/register/verify \
  -H "Content-Type: application/json" \
  -d '{"email": "dev@example.com", "code": "482901"}'

The api_key field in the verification response is your key. It is shown once - store it securely.

Multiple Keys

Each account can have multiple named API keys, managed via the control panel. Use separate keys for different applications or environments to scope access and simplify rotation.

Key Rotation

Generate a new key in the control panel, update your application, then revoke the old key. Both keys work simultaneously during the transition.

Security

Store keys in environment variables or a secrets manager, not in source code
Use sandbox keys (mfx_test_) during development and testing
Rotate keys immediately if you suspect a leak
Each key is scoped to a single environment

Get Started

Environments

Billing

Errors

Header Format

Key Types

Getting Your First Key

Multiple Keys

Key Rotation

Security

​Header Format

​Key Types

​Getting Your First Key

​Multiple Keys

​Key Rotation

​Security

Header Format

Key Types

Getting Your First Key

Multiple Keys

Key Rotation

Security