Contract-first
An OpenAPI 3.1 or GraphQL SDL contract reviewed and mocked before a line of logic is written.
API Development
APIs other teams actually enjoy consuming
We design and ship production APIs — payment and billing endpoints, partner and marketplace integrations, mobile and SPA back-ends, internal service meshes. Our API development services cover contract-first REST and GraphQL design in OpenAPI 3.1, OAuth2 security, idempotent writes, cursor pagination, and webhook delivery with retries — built in Node.js/NestJS, .NET, Python/FastAPI and Go. Clean contracts, real docs, no black boxes.
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0Years of experience
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0In-house engineers
0Code & IP ownership
Why it matters
Most APIs don't fail on the happy path
They fail on the edges — a breaking change shipped without a version bump, a webhook that silently drops, a POST that double-charges on retry, an integration that falls over the first time a third-party returns a 429. Our API development is built to survive those edges: contract-first design so consumers never guess, idempotency keys so retries are safe, exponential-backoff and dead-letter queues so nothing is lost, and deprecation headers so nobody wakes up to a 404. That is what separates real API software development from a folder of undocumented endpoints.
Safe to retry
Idempotency keys, at-least-once webhooks and dead-letter queues, so failures don't corrupt data.
Hardened
OAuth2/OIDC, scoped keys, per-client rate limits and OWASP API Top 10 coverage.
What we do
API development services, end to end
From a single custom API development sprint to a full backend platform and every integration in between. Pick the scope you need — here is exactly what each one includes.
Custom API Development
Custom API development that starts from your domain model, not a template:
- We write the OpenAPI 3.1 / GraphQL SDL contract first, then review it with your front-end and partner teams
- We generate types, server stubs and mock servers so client work starts on day one
- Idempotency keys on writes, cursor pagination, RFC-7807 problem+json errors, semantic versioning with
DeprecationandSunsetheaders - Contract tests in CI so a breaking change can never merge unnoticed
REST API Development
Resource-oriented REST API development with the details that decide whether an API is a pleasure or a pain: correct verbs and status codes, ETags and conditional requests, cursor-based pagination, idempotency keys on POST/PATCH, consistent error envelopes, and a documented versioning and deprecation policy.
Web API Development (GraphQL)
Web API development for SPAs and mobile — a single typed GraphQL schema with DataLoader batching to kill N+1 queries, persisted queries to cap payload abuse, subscriptions over WebSockets for live data, and field-level authorization so clients only see what they should.
API Integration Services
API integration services that stitch your own stack together — CRM, ERP, billing, data warehouse. We build an integration layer that maps schemas between systems, handles retries and backpressure, dedupes with idempotency, and keeps an audit trail of every sync so you can prove what moved where and when.
Custom API Integration
Custom API integration for the systems that ship no clean connector — legacy SOAP, undocumented endpoints, flat-file feeds, screen-scraped portals. We build adapters, normalize inconsistent payloads, reconcile data both ways, and wrap it all behind one sane internal API your team can actually use.
Third-Party API Integration
Third-party API integration with the services you rely on: Stripe and PayPal for payments, Twilio and SendGrid for messaging, Salesforce and HubSpot for CRM, QuickBooks and Xero for accounting, EasyPost and Shippo for shipping. OAuth2 app onboarding, webhook signature verification, and exponential-backoff retries for the inevitable 429s and 5xxs.
Backend API Development
Backend API development with a microservices or modular-monolith architecture chosen to fit your team size — an API gateway for auth, routing and rate limiting, async messaging over Kafka, RabbitMQ or SQS for event-driven flows, and distributed tracing so you can follow one request across every service.
Security, Docs & Support
OAuth2/OIDC, short-lived JWTs with rotation, mTLS for service-to-service calls, scoped API keys and per-client rate limits, hardened against the OWASP API Top 10. Shipped with interactive OpenAPI docs, generated SDKs, a sandbox, and monitoring with alerting so regressions are caught before your consumers notice.
Have an integration that keeps breaking?
Book a free consultation and we'll audit your API or integration and map a fix.
Architecture
Patterns we reach for
The right tool for the load — not a one-size-fits-all stack bolted onto every project.
Event-Driven & Webhooks
Kafka/SQS events, outbound webhooks with signing, retries and replay.
API Gateway
Kong, AWS API Gateway or Azure APIM for auth, throttling and versioning.
GraphQL Federation
One graph across many services, each team owning its own subgraph.
gRPC Internally
Low-latency, strongly-typed service-to-service calls behind a REST edge.
Serverless APIs
Lambda/Cloud Functions for spiky, pay-per-use endpoints.
AI & LLM APIs
Streaming endpoints, token budgeting and caching in front of model calls.
Need to scale a backend team fast?
Hire API developers from us — senior back-end engineers in REST, GraphQL, microservices and integrations, embedded in your workflow.
How we work
Contract-first, test-backed delivery
The same disciplined process behind every API we ship — so integration starts early and stays predictable.
Model & contract
Domain modelling, then a versioned OpenAPI/GraphQL contract signed off by every consumer.
Mock & parallelise
Mock servers and generated types let front-end, mobile and partners build against day one.
Build
Endpoints shipped in two-week sprints with auth, validation and pagination from the start.
Test
Unit, contract and k6 load tests in CI — with real latency and error-rate budgets.
Ship
Gateway, rate limits, OpenAPI docs, SDKs and dashboards wired and verified at go-live.
Operate
Versioning, deprecation windows, new endpoints and 24/7 monitoring keep it healthy.
Technology
The API stack we build on
We pick the language and tooling that fit your latency, team and budget — not the other way round.
Node.js / NestJS
Python / FastAPI
.NET
PHP
Laravel
Go
GraphQL
OpenAPI / Swagger
PostgreSQL
Redis
Docker / K8s
AWS
Why Sumedha Softech
An API development company that hands over more than code
Your APIs are infrastructure — they have to stay reliable for years and stay legible to the next engineer. As an API development company we ship the contract, the tests, the docs and the dashboards alongside the code, so nothing about your API is a mystery.
The contract is the source of truth
OpenAPI/GraphQL specs, generated SDKs and a sandbox — not tribal knowledge.
Security & reliability
OWASP API Top 10 coverage, load-tested to a target p95 latency and error budget.
15+ years, 700+ projects
Proven back-end engineering with a 5.0 rating on Clutch.
Dedicated in-house teams
Hire API developers who are senior, full-time and yours — never anonymous subcontractors.
Versioned, never breaking
Additive changes, deprecation windows and consumer contract tests protect every client.
You own it
100% of the source, specs and IP is yours — no lock-in, no per-seat licence.
FAQ
API development, answered
The questions engineering leads actually ask us. Still curious? We're one message away.
Ask us anythingREST or GraphQL — which should we build?
Depends on your consumers. REST API development is simpler to cache and reason about and is ideal for public and partner APIs; GraphQL shines when clients need to fetch varied, nested data in one round trip, as in SPAs and mobile. We often ship a REST edge with GraphQL or gRPC internally, and recommend the fit after seeing your data and clients.
Can you take over an existing API or integration?
Yes. We start with an audit — reverse-engineer the current behaviour into an OpenAPI contract, add contract and load tests to pin down what it does today, then refactor safely behind versioning. Most of our custom API integration work begins exactly this way.
How do you keep third-party API integration from breaking?
We treat every third-party API integration as unreliable by default: signed webhooks with replay protection, exponential-backoff retries with a dead-letter queue, circuit breakers around flaky vendors, idempotency so a retried call never double-acts, and alerting when a provider starts returning 429s or 5xxs.
How do you version APIs without breaking clients?
Changes are additive first. Breaking changes go behind a new version (URL or header) with Deprecation and Sunset headers and a documented window, and consumer contract tests fail the build if an existing client would break. Nobody wakes up to a surprise 404.
Can we hire API developers to extend our team?
Yes. You can hire API developers from us as a dedicated pod or to augment your own — senior engineers fluent in REST, GraphQL, microservices, message queues and third-party integrations, working in your repo, tools and stand-ups.
Do we own the code, specs and docs?
Completely. You receive 100% of the source, the OpenAPI/GraphQL specs, generated SDKs and full IP rights, with no recurring licence fees on our side after launch.
Let's build
Start your API project
Share a few details about your systems and we'll get back within one business day with ideas, a rough timeline and an honest estimate. Free consultation, NDA on request.
- Free 30-minute consultation
- NDA available on request
- Talk directly to a senior backend engineer