Hire a Senior Backend Engineer: High-Throughput Python (Django, FastAPI), Golang Microservices & PostgreSQL

A resilient software product depends on clean API contracts, idempotent payment and webhook processing, fast database queries, and observable background workers. I am Aldian Fazrihady, a Senior Backend Engineer with 15+ years of production experience building mission-critical backends in Python (Django, Django REST Framework, FastAPI, Celery, Daphne ASGI) and Go (Golang microservices, gRPC, concurrent workers) backed by PostgreSQL and Redis.

1. Core Backend Engineering Specializations

• Python Backend Engineering (Django, DRF, FastAPI, Celery): Asynchronous ASGI WebSockets (Django Channels / Daphne), high-concurrency FastAPI services, distributed Celery task queues with Redis, and strict Pydantic schema validation.
• Go (Golang) High-Throughput Microservices: Low-latency REST and gRPC services, bounded worker pools, context-aware cancellation, and race-free concurrent state management.
• PostgreSQL Performance & Zero-Downtime Migrations: Eliminating N+1 ORM queries, designing composite and partial covering indexes, concurrent index creation (CREATE INDEX CONCURRENTLY), and hybrid relational + pgvector schemas.
• Idempotent Payment & Webhook Engines: Cryptographic HMAC signature verification, dual live/sandbox routing, and automatic status reconciliation for international card checkouts and Indonesian QRIS / Virtual Account payments.

2. Idempotent Webhook & Database Transaction Pattern

from django.db import transaction

def mark_order_paid_idempotently(order_uuid: str, provider_ref: str) -> bool:
    with transaction.atomic():
        order = (
            Order.objects.select_for_update()
            .filter(uuid=order_uuid)
            .first()
        )
        if not order or order.payment_status == "PAID":
            return False
        order.payment_status = "PAID"
        order.provider_reference = provider_ref
        order.save(update_fields=["payment_status", "provider_reference", "modified_at"])
    return True

3. What a Senior Backend Engineer Can Deliver in 1 Day ($100 / Rp 1,000,000)

• Design and ship a production REST/GraphQL/WebSocket API endpoint with automated unit and integration tests.
• Diagnose and fix slow PostgreSQL queries, connection pool exhaustion, or Celery memory leaks.
• Integrate secure payment checkouts, webhook signature verification, or transactional HTML email delivery via AWS SES.