Why aggregator-only routes fail in emerging markets
Most SMS API providers use a tiered aggregator model: messages go through 2–4 hops before reaching the destination operator. Each hop adds latency, drops grey routes during congestion, and reroutes through cheaper paths that often have higher failure rates. For India alone, aggregator-route OTP delivery rate during business hours can drop to 78% — meaning 22% of users never receive their code, retry, complain, or churn. Direct-operator agreements (Vodafone Idea, Airtel India, Telkomsel Indonesia, Viettel Vietnam, Globe Philippines) cost more per message but deliver 95%+ reliably. We aggregate direct routes for the high-failure markets and use aggregator fallback for low-volume tail.
Routing architecture
Each SMS request enters our routing layer with destination MCC/MNC, message category (OTP / promotional / transactional), and priority tier. The router selects: direct route (when covered and priority allows), Tier 1 aggregator (Sinch, Infobip), or Tier 2 fallback (Twilio, MessageBird). For OTP we always prefer direct route if available. Real-time delivery report (DLR) feedback retrains the router weekly — routes with >5% delivery failure get demoted automatically. WhatsApp Business API runs on a separate path with our Meta-approved BSP partnership.
Delivery rate benchmarks
Measured 30-day rolling delivery rate (excluding obvious invalid numbers): India direct-operator route 96.4% / aggregator route 81.2%. Indonesia direct 97.1% / aggregator 88.5%. Vietnam direct 95.8% / aggregator 79.4%. Philippines direct 96.9% / aggregator 86.1%. Pricing for direct routes runs $0.018–0.042 per OTP depending on operator. WhatsApp Business utility messages: $0.005–0.015 per conversation depending on country.
Routing posture
We route OTP, transactional notifications (delivery, payment confirmation), and promotional messages with proper opt-in. We require sender ID registration where mandated (DLT in India, AIS/DTAC in Thailand, Telkomsel in Indonesia). We block: phishing-pattern messages, promotional messages without unsubscribe instructions, messages to numbers on national DND registries (where enforced), and bulk political messaging during election quiet periods (where regulated). High-volume customers get dedicated compliance review at onboarding.
Anonymized case outline — An Indonesian fintech with 1.4M users sending ~3.2M OTP/month migrated from a single-aggregator setup. Pre-migration delivery rate: 87% (aggregator-only). Post-migration: 96% (direct Telkomsel + Indosat + XL routes, with aggregator fallback). Customer-side: signup conversion improved 9.2%, support tickets for 'didn't receive code' dropped 71%. Per-message pricing increased 14% but ROI was strongly positive on conversion alone. Settlement monthly via wire or stablecoin per customer preference.
FAQ
Sender ID registration?
Yes for India DLT, Indonesia, Thailand, UAE, Saudi. We handle the registration paperwork as part of onboarding for direct routes.
100k+ OTP/hour bursts?
Indian direct routes can absorb 50k/min sustained, Indonesia 30k/min, Vietnam 25k/min. Higher bursts use aggregator overflow with documented failover.
WhatsApp Business setup time?
Meta BSP onboarding typically 5–10 business days from approved Facebook Business Manager + verified phone number. We assist with template approval.
Voice OTP fallback?
Available for India, Indonesia, Brazil. Triggers automatically after 60 seconds of unredeemed SMS OTP.
Talk to our infrastructure team
MNDA standard. Multi-channel: email, scheduled call, or Telegram. We respond within 4 business hours.