Sellavie.ai — AI Social Sales Agent

Multi-tenant FastAPI backend that automates Instagram, Facebook, and WhatsApp conversations and connects them to order, invoice, and payment workflows.

Python 3.11FastAPISQLite (runtime)React 18 + ViteMeta Graph APIsOpenAI / Anthropic / GroqPaystack / Flutterwave / StripeNginxJWT + refresh rotation + TOTP 2FAFernet encryption

Live site Technical case study

This project is private because it is an actively deployed commercial SaaS platform.

Tenancy

business_id isolation

Rate limit

100 req/min per IP

Auth

60m access / 30d refresh

Payload caps

2MB default, 10MB uploads

Project Overview

Sellavie.ai is a backend-first AI social sales platform. The system maps each inbound social event to the correct tenant, generates context-aware responses, and executes order/invoice/payment actions with verified webhooks and controlled side effects.

Challenge

Businesses lose revenue when social DMs are answered late, handoffs are inconsistent, and order/payment follow-through is handled manually across channels.

Solution

Built a multi-tenant backend that ingests webhooks, resolves tenant context, generates AI replies with provider failover, and executes commerce actions (orders, invoices, payment status updates) using server-side action parsing.

Results

Deployed a live system used by real businesses with webhook-based messaging, multi-provider AI orchestration, payment callback reconciliation, and analytics endpoints for conversation and transaction monitoring.

Architecture

FastAPI monolith handles auth, tenant management, webhook ingestion, AI orchestration, and commerce APIs.
Tenant isolation is enforced with business-scoped records (`business_id`) and owner/team access checks.
Meta webhooks are signature-verified, dispatched by platform type, and mapped to tenant integration IDs.
AI provider chain runs preferred-first failover (OpenAI -> Anthropic/Groq) with safe fallback replies.
Internal action tags drive server-side side effects for handoff, checkout, invoice, and payment states.
React SPA is served behind Nginx, which proxies `/api` to FastAPI.

Key Engineering Highlights

Designed owner + team-member tenant access model with JWT access/refresh rotation and optional TOTP 2FA.
Built webhook ingestion for Instagram, Facebook, and WhatsApp with deterministic tenant routing from integration IDs.
Implemented state-machine-style AI routing by parsing internal control tags and separating text from actions.
Added background task execution for notification and invoice side work using async tasks and worker threads.
Built payment and transaction synchronization via verified webhooks across Paystack, Flutterwave, and Stripe.
Added reliability controls: duplicate order guardrails, provider failover, payload caps, and defensive error handling.

Security & Privacy

HMAC webhook verification for Meta and payment providers before processing side effects.
Bcrypt password hashing, signed JWT access/refresh tokens, refresh-token rotation, and optional TOTP 2FA.
Fernet encryption plus response masking for sensitive payment configuration fields.
Request hardening with rate limits, scanner path blocking, and payload size limits.
Audit-oriented activity logs and generic client error responses to reduce data leakage.
Consent withdrawal, data export, account deletion, and Meta deauthorize/data-deletion callback endpoints.