Routing by phone number identifier
Every inbound webhook is resolved to its tenant before touching the application. Onboarding a new client goes through Meta's Embedded Signup, with no manual steps.
1 instance → N clients · Mass communication industry
Omnichannel messaging
Multi-tenant platform on top of WhatsApp for retail
webhook → tenant
POST /webhooks/whatsapp
phone_number_id1049…
tenantclient_b
inboxisolated
sidekiq · redisqueued
postgres.transactionok
The problem
Each client needed its own WhatsApp number and its own inbox, on a single shared instance. Standing up a full installation per client multiplied servers, updates and certificates.
The decision
Resolve the tenant at the edge, by phone number identifier, before the webhook touches the application. Anything that cannot be left half-done lives in PostgreSQL.
Atomic logic in PostgreSQL
Operations that cannot be left half-done live in the database, with constraints and transactions, preserving integrity under load instead of trusting execution order.
Docker, Caddy and Sidekiq
Container orchestration, TLS and reverse proxy with Caddy, and asynchronous pipelines in Sidekiq on Redis for everything that must not block a request.
The result
Real multi-tenancy without duplicating infrastructure: 45 accounts on a single instance, and onboarding a new one stopped being a full deployment.
45
Accounts in production
+500,000
Inbound messages per month
1
Instance for all of them
Tech sheet
- Role
- Backend Lead. I design and maintain the platform's backend.
- Project base
- Self-hosted open source platform, in Ruby on Rails, which I extend
- Data and queue
- PostgreSQL with atomic logic · Redis · Sidekiq
- Infrastructure
- Docker and Docker Compose · Caddy · self-hosted VPS
- Integrations
- WhatsApp Cloud API · Meta Embedded Signup · n8n · Evolution API
- Clients
- Retail. Under a confidentiality agreement, I do not name them.
Next case
Skin Studio
Appointments and e-commerce built end to end, with the business rules in the domain
Shall we work together?
Let's talk.
I design it, build it end to end and take ownership of keeping it running. Write to me and let's talk. I reply the same day.