Wagend

Inbound: a message hits the webhook, has its SHA-256 signature validated, resolves to a Contact, is logged to the conversation, atomically bumps the inbox thread's unread state in SQL, and is pushed to the client through the notifications gateway — then a trigger engine fires any keyword auto-replies.

Real-time: a Redis presence registry holds a userId→serverIds map — which pods currently hold each agent's device sockets — under TTL keys, and every pod subscribes to its own channel. To deliver, a service looks the recipient up and publishes a targeted payload to only the pods holding their sockets (all their devices at once) instead of broadcasting to every pod; the Socket.io Redis adapter still carries room fan-out where a genuine broadcast is wanted. Typing indicators go to the workspace room but skip the sender's own room, so your desktop doesn't echo what you're typing on your phone.

Broadcasts never run in the request: the audience is chunked onto BullMQ queues, the API returns immediately, and workers merge personalization tags and send through a gateway-provider abstraction (Meta or Twilio), writing a log per message. A p-limit concurrency manager holds sends under Meta's per-number ceiling.

Billing is a credit economy enforced at two gates — an entitlements service (plan cached in Redis, 5-minute TTL) checks quota and a credit ledger debits the wallet, with a dual-enforcement service that refunds on failure. Stripe checkout and webhooks are processed idempotently on a BullMQ queue.

The AI layer routes through OpenRouter (multi-model, bring-your-own-key) for draft replies and summaries, and an agent pipeline parses, chunks and embeds each tenant's knowledge base into Qdrant, then retrieves against it to ground replies.