WhiteBooks at Scale

WhiteBooks processes 30+ Crore IRNs per year, peaks at 1.6 million IRNs in 24 hours, and sustains p50 IRN latency of 87 milliseconds. The architecture is multi-tenant, horizontally scalable, idempotent on the request envelope, and built for ERP-grade concurrency. Zero-downtime deployments ship multiple times per week without an SLA-impacting outage in the last 18 months.

Headline numbers (rolling 90 days)

Scale patterns we engineer for

• Horizontal scaling — gateway tier auto-scales on CPU + connection-count metrics. No single-instance bottleneck.
• Multi-tenant isolation — every request scoped by client_id; rate-limit budget and idempotency keys partitioned per tenant. One noisy tenant cannot starve another.
• Idempotent envelopes — every state-changing endpoint accepts an idempotency key (custom header). Duplicate requests within the dedup window return the original response without re-executing.
• Distributed retry queue — transient upstream failures (IRP / NIC timeouts) enter a queue with exponential backoff (1s → 2s → 4s → 8s → 16s). After 5 retries the job moves to a dead-letter queue with full request context for support investigation.
• Bulk-first design — bulk endpoints accept 1,000 entries per call and count as a single rate-limit unit. Customers processing high volume save both money and latency.
• Webhook back-pressure — outbound webhook delivery is rate-limited per receiver URL. We won't accidentally DDoS your endpoint with a million events.

Zero-downtime deployments

Blue-green deploys via Cloudfront-managed traffic shifting. New version receives 1% of traffic for 15 minutes, then 25%, then 100%. Each step gated by error-rate + latency checks. If any check trips, traffic shifts back to the previous version automatically. The customer never sees a deployment.

Customer-side load patterns we support

• Steady-state ERP — typically 10–100 IRNs/min spread over business hours. Plenty of headroom on Starter or Growth tiers.
• End-of-day batch — manufacturing customers post 1,000–10,000 invoices in a 30-minute window. Use bulk endpoints; Business or Enterprise tier.
• Marketplace event-driven — e-commerce flash sale → 100s of IRN requests per second for 1–2 hours. Enterprise tier with burst-rate.
• CA bulk filing — month-end GSTR-1 / 3B for 500+ clients. Bulk endpoints with webhook completion notifications.

Related

Part of the WhiteBooks Enterprise cluster. Last updated 27 May 2026.