What are SMS short codes?
Short codes are 5 – 6 digit numbers used by businesses to send high-volume, application-to-person messages. These include:
- One-time passwords (OTPs)
- Two-factor authentication (2FA)
- System alerts and transactional messages
- User verification links during sign-up or login flows
They’re wideley adopted by some of the worlds most famous brands.
More on short codes: Twilio glossary.
Why it matters for QA & automation
Many systems send OTPs via short code numbers only, particularly industries like fintech, retail and SaaS. If your testing tool can’t receive messages from short codes, your:
- MFA workflows may fail silently
- OTP verification flows can’t be automated
- Critical coverage for login, password reset, and onboarding is lost
This is exactly what happened to a leading fintech company. They were using a competitor for both email and SMS testing, but when they dropped short code support, their automated OTP verification broke.
They switched to Mailosaur because we still accept SMS from both long codes and short codes, without restriction.
Mailosaur: Full SMS testing coverage
Mailosaur’s SMS testing features include:
Feature Supported?
Inbound SMS from short codes ✅ Yes
Inbound SMS from long codes ✅ Yes
SMS OTP code extraction ✅ Yes
Email & SMS testing in same test ✅ Yes
REST API & SDKs (JavaScript, Python, etc.) ✅ Yes
Works with Playwright, Cypress, Selenium ✅ Yes
Supports CI/CD integration ✅ Yes
Example test flow:
const message = await mailosaur.sms.get(serverId, {
sentTo: 'test@your-sms.mailosaur.net'
});
const otp = message.sms.body.match(/\d{6}/)[0];
await page.fill('#otp-input', otp); Who’s using it?
- Dominos- to test transactional SMS sent from short codes
- Fintech platforms- for high-volume OTP validation
- Booking platforms- to test customer login flows and booking confirmation codes.
If your current tool doesn’t support short codes, it’s not a feature gap, it's a blocker!
Mailosaur continues to offer short code compatibility so you can run complete, real-world automated tests with confidence.
Ready to test SMS from short codes again? Start a free trail with Mailosaur, or reach out and talk to our team if you want to migrate your suite.