SMS verification codes, two API calls
Add SMS OTP to your app or store with send_otp and verify_otp. Codes of 4-8 digits, expiry from 1 to 60 minutes, abuse protection included. In Romania an SMS costs about 0.035 EUR.
- Two REST endpoints
- 4-8 digits, custom expiry
- Templates in 9 languages
- verify_otp is free
Users forget passwords, orders sit unconfirmed, fake accounts pile up. An SMS verification code fixes all three. RCSZilla gives you a REST API with two endpoints, Bearer token authentication and message templates already translated into 9 languages.
What you get in the verification API
Two endpoints, nothing more
POST to send_otp delivers the code, POST to verify_otp validates it. Bearer token authentication. Full documentation at docs.rcszilla.com, plus a ready-made n8n integration.
Configurable code and expiry
Choose a code length of 4 to 8 digits, an expiry between 1 and 60 minutes and the maximum number of attempts. You decide how strict verification is.
Abuse protection included
At most one OTP per 60 seconds per recipient. Nobody drains your credits with repeated requests to the same number.
Templates in 9 languages
Customizable message templates per language, with the {code} and {expiry} variables. Pass the lang parameter and the user gets the code in their own language.
Three delivery routes
The channel parameter takes sms or email. For SMS you pick the route: the RCSZilla network, or your own Android phone where sending is free. Email goes out through your own SMTP servers.
History and stats in the dashboard
See codes sent, verified and failed, plus credits used. Send a test OTP straight from the interface before writing a line of code.
Add OTP in three steps
Create your free account
No card, no subscription. Authenticate requests with a Bearer token and you are ready for the first call.
Send the code
POST to https://app.rcszilla.com/api/?endpoint=send_otp with recipient, channel, lang and ref_id, for example your order id. The user receives the code by SMS or email.
Verify the code
The user types the code into your app, you POST to verify_otp. Verification is free, you pay only for the SMS sent.
What it costs
You pay only for the SMS messages you send, from prepaid credits. In Romania an SMS costs about 0.035 EUR. Verifying the code is free, no matter how many verify_otp calls you make.
- No subscription and no monthly fees
- Prepaid credits never expire
- verify_otp is free, you pay only for the SMS sent
- Free when sending through your own Android phone
- Free account, no card needed
Frequently asked questions
How much does one SMS code cost?
In Romania, an SMS costs about 0.035 EUR. Verification through verify_otp is free. If you send through your own Android phone, the SMS costs nothing.
How do I start and how long does integration take?
Create a free account, no card needed. The API has two REST endpoints, authenticated with a Bearer token and documented at docs.rcszilla.com. Send a test OTP from the interface first, then connect your app. For n8n there is a ready-made integration.
What if the user does not receive the code?
You see the status of every code in the dashboard: sent, verified or failed. After 60 seconds you can send a new code to the same recipient. As a fallback, send the same kind of code by email through your own SMTP servers, changing only the channel parameter.
Do I need a subscription or a card?
No. The account is free and asks for no card. You buy prepaid credits when you need them, and they never expire. There are no monthly fees.
Can I tie each code to an order in my system?
Yes. Pass the ref_id parameter with your own reference, for example the order or user id, and find it back in the history. You control the message text in the templates, with the {code} and {expiry} variables, separately for each language.
More RCSZilla solutions
Send your first code today
Create the free account, send a test OTP from the interface, then connect your app to the API. No card, no subscription.
Create free account