Blog

Plain-English summary of RBI's April 2026 mandatory 2FA rules for digital payments, what counts as a valid second factor, and how OTP fits in.

How smishing attacks trick users into handing over OTPs in India, the warning signs, and the product, copy, and infrastructure changes that defeat them.

How SIM swap fraud bypasses SMS OTP in India and the layered defenses (silent network auth, device binding, step-up checks) that keep your users safe.

How attackers exploit OTP send endpoints with bots and SMS traffic pumping schemes — and the rate limits, fingerprinting, and routing controls that stop them.

Key lifecycle for SMS OTP APIs: dual-key cutover, secrets storage, incident response, and protecting credentials used for TRAI DLT-compliant sends.

Choose a verification channel for Indian products: when TRAI-compliant SMS OTP wins, when email magic links help, and when TOTP fits—plus how DLT-free OTP APIs fit an SMS-first stack.

Design phone OTP flows for high traffic: idempotency, rate limits, fraud signals, fallbacks, and observability—aligned with TRAI DLT transactional SMS expectations for Indian login and payments.

Best practices for OTP time windows, max verification attempts, lockout strategies, resend cooldowns, and the UX tradeoffs developers need to consider.

Learn what SMS pumping and OTP fraud are, how artificial inflation attacks work, detection signals, prevention techniques, and how to protect your SMS budget.

Compare SMS OTP and WhatsApp OTP for delivery rates, cost, user experience, and reliability in India. Learn when to use each and how to set up fallback strategies.

Learn proven rate limiting strategies for OTP APIs: per-phone, per-IP, and sliding window approaches to prevent SMS pumping and brute force attacks.

Learn how to secure OTP systems with bcrypt hashing, rate limiting, expiry windows, attempt limits, HTTPS enforcement, and idempotency keys.