aut2fa FAQ
aut2fa is an API that sends one-time verification codes (OTP, 2FA). This page answers the common questions about it: how test keys work, what happens to a code that isn't delivered, retries, rate limits, pricing and WhatsApp delivery. Each answer is also on the page it belongs to.
Updated on
Questions
How do test keys work?
Keys that start with ak_test_ are free, and codes aut2fa generates in test mode are always 000000. Automated tests can run the whole flow without touching your balance.
What if a code isn’t delivered?
Nothing. The send is marked as failed, your balance stays the same, and your statement shows the failure.
How do you protect against SMS pumping?
Every account has a ceiling on sends per minute. You can also turn on limits per application: sends per minute and sends per recipient per hour. Requests over a limit get a 429 with a Retry-After header, before anything is sent.
Is it safe to retry a request?
Yes, with an Idempotency-Key header. Repeating a request with the same key returns the original send instead of sending a second code.
Can I send my own code?
Yes. Pass it in the code field, or leave the field out and aut2fa generates one. Set locale to en or pt-BR to choose the message language.
Pricing questions
Is there a free plan?
Yes. New accounts receive 10 free live sends through any channel. After using this allowance, add balance to keep sending. Test keys (ak_test_) are free and run the whole flow with the code 000000.
Which channels can I use today?
The tables above list the channels currently available for delivery. Each shows suggested quantities, the total cost and the price per code.
Do I pay for codes that aren't delivered?
No. A send that no channel delivers is marked failed and costs nothing; your statement shows the failure.
Can I pay in another currency?
Not today. Balance and prices are in Brazilian reais (BRL).
WhatsApp OTP questions
What if the phone number has no WhatsApp?
aut2fa can't deliver the code, so the send ends as failed and costs nothing.
How long is the code valid?
10 minutes from the moment you create the send. After that, /verify answers with verification set to expired.
What happens after 5 wrong codes?
The send is locked: verification becomes locked and no further code is accepted. Create a new send to try again.
Can I test for free?
Yes. Keys that start with ak_test_ are free and the code aut2fa generates for a test send is always 000000, so automated tests run the whole flow without touching your balance.