SMS verification testing for software teams
Shipping phone verification without testing it is risky. Parsing errors, timeout handling, and user messaging all need exercise against real SMS delivery — but tying tests to personal SIM cards does not scale. SMSTwins gives engineering teams temporary virtual numbers, a REST API, and webhooks to validate OTP flows in development, staging, and CI.
Why automate OTP testing
Registration, login recovery, and two-factor paths should behave consistently across regions. Automated tests that request a number, wait for webhook delivery, and assert code format catch regressions before production.
Manual QA with personal phones creates bottlenecks and privacy leaks. Dedicated verification infrastructure keeps tests repeatable and isolated.
API surface
Authenticate with API keys (sk_live_ or sk_test_ for sandbox). Discover catalog endpoints without auth; purchase activations and rentals with keys. Webhooks POST signed JSON when SMS arrives or sessions change state.
The Simple API offers plain-text responses for shell scripts. OpenAPI documentation and code examples accelerate integration.
Rate limits and loyalty tiers
Limits follow your loyalty rank — up to 600 requests per minute at Platinum. Sandbox keys read catalog and balance but cannot purchase activations, letting you validate auth without spend.
Loyalty discounts reduce per-activation cost for teams that verify frequently in test environments.
Provider-quality routing
Tests should reflect production-like delivery. SMSTwins uses quality-scored SIM routes rather than fragile VoIP stand-ins, so staging results better predict live behavior.
Automatic refunds on timed-out activations align incentives — you pay for working verification, not failed silence.
Getting started in engineering
Create an account, issue an API key, and call POST /activations with your target service and country. Poll or subscribe via webhooks, then assert OTP handling in your application.
Read API Terms of Use and security practices: never expose keys in browser code, verify webhook signatures, and prefer webhooks over aggressive polling.
Developer SMS verification FAQ
- Is there a sandbox mode?
- sk_test_ keys support catalog and balance reads without purchasing activations. Use live keys in controlled staging when you need real SMS.
- How do webhooks sign payloads?
- HMAC-SHA256 over the raw JSON body using your webhook secret. Compare to the signature header documented in the Webhooks section.
- Can we test multiple countries?
- Yes. Catalog endpoints list countries, services, and live prices. Matrix pages cover popular combinations for SEO reference.