OTP Verification for the UK

SMS delivery

Six-digit codes delivered by SMS to any UK mobile (+44).

10-minute expiry

Codes expire automatically, so there are no stale tokens to leak.

Attempt lockout

Five wrong attempts and the code is locked — brute force stops here.

Pay per verification

One credit per delivered code. No monthly fee, no minimum.

Integration

Two calls. That's the whole flow.

Nothing to install and no webhooks to wire up. Send a code, verify the code, and your user is authenticated.

1

Send a code

POST to /v1/otp/send with the recipient's UK number. Bremlio generates a six-digit code and texts it.

2

Verify the code

Your user types the code. POST it to /v1/otp/verify with the verification id and Bremlio confirms whether it matches.

3

Done

The user is verified — log them in, approve the transaction, or complete the signup.

verify.js

// Step 1: send the code
const { verification_id } = await fetch(
  "https://api.bremlio.com/v1/otp/send", {
    method: "POST",
    headers: {
      "X-Api-Key": API_KEY,
      "Content-Type": "application/json"
    },
    body: JSON.stringify({ to: "+447700900123" })
}).then(r => r.json())

// Step 2: verify what the user typed
const { verified } = await fetch(
  "https://api.bremlio.com/v1/otp/verify", {
    method: "POST",
    headers: {
      "X-Api-Key": API_KEY,
      "Content-Type": "application/json"
    },
    body: JSON.stringify({ verification_id, code: userInput })
}).then(r => r.json())

if (verified) {
  // ✅ user authenticated
}

Try it

Test the OTP flow live

Enter your API key and a UK number to send a real code now. No key? Sign up free → — you get 25 credits to test with.

Verify UK users in seconds, not minutes