Backend Development Services

Typed FastAPI services, Postgres as source of truth, Redis for cache. Backends that don't page you on a Friday.

SQL Postgres
MySQL
NoSQL MongoDB
Redis
Vector Pinecone
pgvector
DATA LAYER
FastAPI · Python
POST /leads 200
84ms · auth: jwt
CORE ENGINE
Payments Stripe
Razorpay
LLMs OpenAI
Claude
Storage S3
R2
SERVICES
The stack we ship with

What we use. Why we pick it.

  • 01FastAPI

    Handles every request between your app and its data. Bad input gets rejected before it reaches the database, and API docs write themselves.

  • 02Postgres with reversible migrations

    Your database. Every structural change is versioned, reviewed, and reversible - no gambling on deploy day.

  • 03SQL Server (when the customer already runs it)

    Already on Microsoft? We work with what you have. Same architecture, different database underneath.

  • 04Redis

    Fast memory layer that keeps your app snappy under load. Sessions, rate limits, and job queues live here instead of hammering the database.

  • 05Celery

    Background work that should not block the user - emails, reports, file processing - runs quietly on its own schedule.

  • 06WebSocket + Socket.IO

    Live updates without refreshing. Prices, bid counters, order status - changes appear the moment they happen. Shipped on gold trading, live auctions, and delivery tracking.

  • 07S3-compatible object storage

    Where uploaded files live. Access goes through short-lived signed links, so only the right person gets to the right file.

  • 08Auth (JWT, OAuth2, SSO)

    Login via email, Google, GitHub, or company SSO. Access rules enforced at the server - removing a button on the frontend does not actually remove the access.

  • 09Observability (Sentry, Datadog, Grafana)

    We know when something breaks before your users do. Every error traced to the exact commit that caused it.

  • 10CI to wherever you host

    Code ships itself after tests pass - to AWS, Fly.io, Render, or Vercel. One command rolls back if a release goes wrong.

Reference architecture

How it fits together.

  • FastAPI on the hot path
  • Postgres as source of truth
  • Redis for cache
  • Celery for the jobs that would otherwise block a request.
Client App · browser Any frontend
HTTP ›
Hot path FastAPI Pydantic validation async Python · uvicorn OpenAPI auto-docs
SQL ›
Source of truth Postgres Reversible migrations
GET / SET ›
Cache Redis Session · rate · queue
  ›
Media S3 Signed URLs
enqueue ›
Workers Celery Email · imports · cron
Integrations

Wired in, not bolted on.

Providers we have shipped against. No wrapper libraries — direct API integrations, typed, tested, in production.

  • Payments
    • Stripe
    • PayPal
    • Razorpay
    • Apple Pay
    • Google Pay
  • Messaging
    • Twilio
    • Plivo
    • WhatsApp Business
    • OneSignal
  • Auth
    • Auth0
    • Clerk
    • Firebase Auth
    • NextAuth
    • Okta SSO
    • Supabase
  • Maps
    • Google Places
    • Mapbox
    • PostGIS
  • LLMs
    • OpenAI
    • Anthropic
    • Azure OpenAI
    • Google Gemini
    • Perplexity
    See AI Integration Services →
  • Market data
    • Polygon.io
    • Finnhub
    • Alpaca
    • Binance
    • CoinGecko
    • metalpriceapi.com
  • Telco
    • DT One — 130+ operators across 44 countries
  • Other
    • CopyLeaks
    • OpenSearch
    • Lasso Moderation
    • Cloudinary
    • Google Drive

If it ships an API, we can integrate it - REST, GraphQL, SOAP, webhooks, or SDK.

Every integration in production. Typed, tested, and handed over with the source on day one.

Case studies

Three products. One backend stack.

FastAPI in production across payments, trading, and real-time bidding.

  • 01/03
    Cross-border mobile top-up screenshot

    Cross-border mobile top-up

    FastAPI + Postgres ledger against React Native and a React web dashboard.

    Webhook-driven order state machine across DT One's 130+ operator network. Stripe + PayPal settled into one ledger. One backend serving both consumer mobile and reseller web.

    • 130+ Operators
    • 44 Countries
    • 2 Surfaces
    FastAPIPostgresDT OneStripe
    Read full case
  • 02/03
    Sabika Gold - gold trading platform screenshot

    Sabika Gold - gold trading platform

    FastAPI on AWS EC2, Socket.IO live spot price broadcast.

    SQL Server for KYC + holdings. Bucketed historical storage for chart rendering across six timeframes. Shipped on iOS, Android, and web.

    • 3 Platforms
    • 6 Timeframes
    • Live Price feed
    FastAPISocket.IOSQL ServerAWS EC2
    Read full case
  • 03/03
    Live auction bidding screenshot

    Live auction bidding

    FastAPI REST + WebSocket, server-authoritative 30-second timer.

    Atomic bid writes with seen-current-highest conflict handling. OneSignal for auction-start alerts. AWS S3 for vehicle galleries.

    • 30s Timer
    • Atomic Bid writes
    • Real-time Updates
    FastAPIWebSocketOneSignalAWS S3
    Read full case
How we engage

Four phases. One backend.

Week 1

Architecture

Data model, service boundaries, integrations, deploy target, observability strategy. Written down before a single endpoint is typed.

Weeks 2–4

The spine

Database, auth, first three endpoints, CI to staging, Sentry wired, basic dashboard in Datadog or Grafana. The boring bit most projects skip — which is why most projects hurt at month three.

Weeks 5–16

Features

Endpoint by endpoint, with tests. Celery jobs for anything slower than 200ms. Redis for caching on read-heavy paths. We ship to staging every day, to production after a gate.

Weeks 17–20

Hardening

Load tests, rate limits, edge cases, runbooks. The last month is where cheap builds skip steps and good builds pay down technical debt.

Engagement models

Same engineers, different shapes.

Same engineers across every model. The shape changes, the bar does not.

  • MVP sprint

    Most picked

    Fixed scope, fixed timeline, one platform, one to two flows.

    Best for Pre-seed founders validating an idea before fundraising.

  • Full product build

    Discovery to launch, our team owns the delivery. Best for startups and companies without an in-house engineering team.

  • Dedicated team

    Your roadmap, our developers, onboarding in three to five days. Best for scale-ups with an existing product and a backlog that is outrunning the team.

  • Rescue and audit

    Written audit of the codebase, API contracts, and data model - then we rebuild the parts that earn it. Most backend rescue jobs cost less than a full rewrite.

  • Staff augmentation

    Specific backend skills added to your team - FastAPI, Python, Postgres, Redis, Celery. Best for engineering teams filling a named gap without a full hire.

No prices on the page - they depend on scope. Share the brief and we come back with a number.

What you actually get from a modern Python backend

Typed endpoints. Every request and response is a Pydantic schema. The client gets an OpenAPI spec auto-generated from the code. We do not hand-write interfaces. The “backend returned an int where the app expected a string” bug class does not exist.

Async Python. One FastAPI worker handles hundreds of concurrent requests without the thread-per-request tax. Our small services run on a single modest box and handle real traffic.

Migrations you trust. Alembic migrations reviewed like code, rolled forward and rolled back. Schema changes that do not break production on a Friday evening - reversible, staged, reviewed.

OpenAPI that clients consume. Flutter (Chopper), React Native + React (TypeScript via openapi-typescript), Python clients all generated from the same spec. A field rename on the server fails a client build, not production.

When FastAPI + Postgres is the right call

  • Typed API for typed clients - Flutter, React Native, or React on the other end of the wire.
  • Real-time features - WebSocket endpoints are first-class in FastAPI. One stack for REST + sockets.
  • AI and ML integration - Python owns the LLM tooling. Your FastAPI backend is already where the OpenAI SDK and vector stores live.
  • Regulated data - typed contracts make audit easier. We have shipped KYC, AMFI compliance, and PCI-adjacent flows.

Real-time systems we have shipped

  • Server-authoritative live auction timer with atomic bid writes and sticky-session WebSocket upgrades - live auction bidding.
  • Socket.IO live price broadcast from a single upstream subscription fanned out to every connected client - gold trading platform.
  • Live tick stream + rules engine for price alerts with last-seen-price state and exactly-once delivery on reconnect - trading calculator watchlist.
  • Webhook-driven order state machine hitting a ~5-second top-up SLA across 130+ operators and 44 countries - cross-border mobile top-up.

Deploy targets we have shipped to

  • AWS (ECS + RDS + ElastiCache) - enterprise environments, strong IAM.
  • AWS EC2 with Docker for predictable cost and fewer moving parts - shipped for Sabika Gold.
  • Google Cloud (Cloud Run + Cloud SQL) - fast iteration, Firebase-adjacent.
  • DigitalOcean App Platform + Managed Postgres - cost-effective for early-stage.
  • Fly.io - global presence, cheap for small services.
  • Render - simple, opinionated, works for most MVPs.
  • Vercel / Netlify - only for services that live in the same repo as a Next.js app (via Serverless Functions or Edge Runtime).

We meet you at your infrastructure. Picking a vendor is a decision we weigh in on, but it is not a prerequisite to start.

What we will not do

  • Serverless-only for everything. Lambda and Cloud Functions are great for event handlers and scheduled jobs. They are usually the wrong default for a full API because of cold starts, traceability, and cost at scale. We pick case-by-case.
  • NoSQL where SQL fits. 90% of projects that reach for MongoDB regret it at month nine. We start with Postgres and only add other stores when there is a concrete reason.
  • Microservices on day one. Monolith first. Split when a boundary gets painful enough that splitting costs less than not splitting. Most projects never cross that line.
  • ORMs so heavy they write queries you cannot read. SQLAlchemy core + raw SQL where it earns clarity. Abstractions that hide the query plan hide the bug.

Why teams pick us for backend

We run FastAPI, Pydantic, and OpenAPI as one unit. The mobile or web client gets a typed binding generated straight from the server code. Rename a field on the backend, break a client build, catch it in CI. You do not find out a field changed shape because a user’s screen went blank.

Real-time lives in the same app as REST. WebSocket and Socket.IO handlers run next to your regular endpoints, not on a separate service you forget to deploy. Migrations use expand-then-contract so nothing goes down during a rollout. We deploy where you already host (AWS, GCP, Fly.io, Render, Vercel, on-prem) and hand over everything at launch: source, infrastructure-as-code, runbooks, the lot.- React Development - typed-client web apps that talk to this backend.

Pick this instead if

Where to go from here.

Three honest forks in the road. Each page names the stack, the failure mode it avoids, and the kind of product it suits.

mobile

Flutter App Development Services

Flutter apps for iOS, Android, iPad, and web from one Dart codebase. Named state management, typed backend contracts, store pipelines that ship on a Tuesday.

Read
web

React Development Services

React web apps on Next.js App Router. Server Components, TanStack Query, Tailwind + shadcn/ui. Fast by default, typed end to end, tested where it counts.

Read
ai

AI Integration Services

LLMs, RAG, and agents wired into production apps. Server-held keys, swappable models, measurable output. Not a ChatGPT wrapper.

Read
FAQ

Questions people ask before we start.

Why FastAPI and not Django, Flask, or Node?

FastAPI gives three things Django does not: native async, Pydantic validation, and OpenAPI out of the box. On a modern Python project you spend less time writing schemas and more time writing business logic. Flask works but is less typed - we reach for it only on small services. Node for hyper-low-latency webhook handlers or when the team is all JavaScript. Go for a CPU-heavy service that needs one binary.

How do you do database migrations?

Alembic with reversible migrations. Every migration is reviewed like code. Destructive migrations (drops, renames) go through an expand-then-contract pattern so production is never in a broken state during rollout. We have a written runbook for it.

How do you handle authentication and authorization?

JWT for API auth, OAuth2 or SSO via Auth0, Clerk, Firebase Auth, or NextAuth depending on the product. Authorization is RBAC or ABAC at the endpoint level, enforced by FastAPI dependencies. Row-level security on Postgres for multi-tenant apps.

Can you take over an existing backend?

Yes. We audit, document, write a migration plan, and extend. Rewrites are the last resort - usually the right move is to add a strangler service next to the existing one and grow it in.

How do you handle webhook reliability?

Signed webhooks (HMAC), idempotency keys on the receiving endpoint, a Postgres outbox pattern for outgoing webhooks, and Celery retries with exponential backoff. Every webhook has a trace ID. The 'the payment went through but our system missed it' bug class does not land on you.

How do you scale?

We start with a monolith on a single box that can handle real traffic (async FastAPI goes further than most teams expect). We split services when a boundary gets painful enough that splitting costs less than not splitting. We add Redis and Celery where the hot path demands it. We do not microservice on day one.

What observability do you ship out of the box?

Sentry for exceptions, Datadog or Grafana + Prometheus for metrics, structured JSON logs to CloudWatch or equivalent. Every request has a trace ID. Every error points to a commit. On-call runbooks included.

Do you handle deploys?

GitHub Actions runs tests and type-checks on every PR. Merge to main triggers a build and a staged deploy - staging first, then production after a manual gate. Rollbacks are one command (docker tag to the previous image, redeploy). No 'deploy on Friday at 5pm' anxiety.

Start a backend development services engagement

Tell us what you’re building.

Tell us the data model, the integrations, and the deploy target. We reply with an architecture, a timeline, and a scoped proposal for a discovery sprint. NDA signed on request. Response within 1 business day.

Book a 20-min scoping call
The team on the call

Sameer Donga

Founder & Lead Engineer

Shipping Flutter, FastAPI, and AI systems since 2019. Reviews the architecture on every engagement.

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Contact

Tell us what you’re building.

Share the problem, timeline, and where you need the sharpest engineering help. Wherever you’re based, we reply within 1 business day in your time zone.

326, Naroda Business Point, Haridarshan Cross Roads, Shri Balaji Rd, Nava Naroda, Ahmedabad, Gujarat 382330, India
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