OTP tester — send and verify a code online
Walk through the complete OTP flow here, with no account and nothing to install. Enter a number, see the message exactly as it would arrive on the handset, and verify the code — with the real SMSBOX API call shown alongside every step. No real SMS is sent, and that is deliberate: a public form that texts arbitrary numbers gets abused within a day. If you want a real code on your own phone, use free test credits.
The requests and status codes shown here come straight from our own API specification. What you see is exactly what your software will send and receive.
How an OTP flow fits together
Request a code
Your application calls the send endpoint with the user's number. SMSBOX generates the code, stores it and sends the message.
The user receives it
The message arrives on the handset. In Belgium that averages under five seconds thanks to direct operator connections.
Verify the code
The user types the code into your screen and your application submits it to the verify endpoint. That call is free of charge.
Handle the answer
Code 11 means verified, code 51 means the code is wrong. After 10 minutes the code has expired and you need to send a new one.
Why we do not send a real SMS here
A public page that texts any number you type into it is a well-known fraud vector. Attackers make such forms send messages in bulk to number ranges whose revenue they share with an operator — SMS pumping. The bill lands with whoever sends the messages, not with them.
That is why real sending always runs through an account with a verified number. You create an account for free, claim test credits and send a real OTP to your own phone. Same flow, same API — just without the open door.
