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API Development
APIs That Developers Love.

RESTful and GraphQL API development β€” designed first, documented thoroughly, and versioned for the long term.

Get Started β†’ Book Free Call
πŸ”Œ
API Development
βœ“ API Design
βœ“ API Development
βœ“ Auth & Security
βœ“ Documentation
βœ“ Third-Party Integrations
What's Included

Everything in our api development service

πŸ“
API Design

OpenAPI-first, RESTful resource design

βœ“ RESTful resource design
βœ“ OpenAPI 3.1 specification
βœ“ GraphQL schema design
βœ“ Versioning strategy
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API Development

Node.js, Python, Go, Java

βœ“ NestJS REST APIs.
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Auth & Security

OAuth2, JWT, API keys, rate limiting

βœ“ OAuth2 / PKCE flows
βœ“ JWT & refresh tokens
βœ“ API key management
βœ“ Rate limiting & throttling
πŸ“š
Documentation

Swagger UI, Postman, developer portal

βœ“ Auto-generated Swagger UI
βœ“ Postman collection
βœ“ Code samples in 5 languages
βœ“ Webhook documentation
πŸ”—
Third-Party Integrations

Stripe, Twilio, Salesforce, SAP

βœ“ Payment API integration
βœ“ Comms API (Twilio, SendGrid)
βœ“ CRM/ERP connectors
βœ“ Webhook receiver patterns
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API Testing

Contract, performance, chaos testing

βœ“ OpenAPI contract tests
βœ“ Supertest integration tests
βœ“ k6 load testing
βœ“ Chaos engineering basics
FAQ

API
questions

Common questions before you start.

Talk to Us β†’
REST vs GraphQL β€” which should we use?+
REST for straightforward CRUD APIs with clear resource boundaries. GraphQL when clients need flexible queries, you have complex nested data, or multiple client types (web, mobile) have different data needs. We build both professionally and advise based on your specific use case.
Do you provide API documentation?+
Yes β€” every API ships with Swagger/OpenAPI UI, a Postman collection, and code samples in JavaScript, Python, PHP, Go, and Java. For developer-facing APIs, we also build documentation portals with Docusaurus or Readme.
Related Services

Often paired with api development

🌐
web development
Learn more β†’
🟒
Node.js
Learn more β†’
☁
cloud & DevOps
Learn more β†’
πŸ”
QA & Security
Learn more β†’

Ready to get started with api development?

Free discovery call Β· 24hr proposal Β· Fixed-price quote.

Start Your Project β†’
50+
APIs Delivered
4.9β˜…
Rating
REST+GraphQL
Both protocols
48hrs
Start Time
100%
Documented
Our Process

How we deliver

A clear, milestone-based process with no surprises.

01
API Design Workshop
Week 1

Define endpoints, schemas, versioning, and auth approach before any code is written.

02
OpenAPI Spec
Week 1

Full OpenAPI 3.1 spec reviewed and approved. Changes at spec stage cost nothing.

03
Auth & Security
Week 1–2

OAuth2/PKCE, JWT, rate limiting, and IP allowlisting implemented and tested.

04
Endpoint Development
Week 2–5

Each endpoint ships with unit tests, integration tests, and live Swagger docs.

05
Third-Party Integrations
Week 4–6

Payments, CRMs, ERPs, communication APIs β€” connected and tested end-to-end.

06
Load Test & Go-Live
Week 6

k6 load testing, Postman collection, developer docs, and staged production rollout.

Technology

The stack we trust

TOOLS
Backend
Node.js / NestJS
Python / FastAPI
Go / Chi
Java / Spring Boot
TOOLS
Protocols
REST (OpenAPI 3.1)
GraphQL / Apollo
gRPC / protobuf
WebSocket / SSE
TOOLS
Auth
OAuth2 / PKCE
JWT & refresh
API key mgmt
Rate limiting
TOOLS
Docs & Testing
Swagger UI
Postman/Newman
k6 load tests
Contract testing
Why Nexcode

Why clients choose us

πŸ“
Design First

OpenAPI spec before any code. Zero ambiguity between design and implementation.

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100% Tested

Every endpoint β€” unit, integration, and contract tests β€” before it ships.

πŸ“š
Docs Included

Swagger UI, Postman collection, code samples in 5 languages. Always.

πŸ”
Security Built-In

OAuth2, JWT, rate limiting, OWASP checks on every project, not as add-ons.

Client Reviews

What clients say about our work

"

Nexcode designed and built our entire partner API β€” 47 endpoints, OAuth2, webhooks, and a developer portal β€” in 9 weeks. Their OpenAPI-first process meant zero rework. We onboarded 12 partners in month one.

RM
Rachel Moore
VP Engineering, ConnectPlatform
β˜…β˜…β˜…β˜…β˜…
Verified Review
β˜…β˜…β˜…β˜…β˜…

"GraphQL API handling 8M queries/day at 99.97% uptime. Query complexity limits and caching layer were production-ready on day one."

DK
Daniel Kim
CTO, Streamify
β˜…β˜…β˜…β˜…β˜…

"Migrated REST to gRPC for internal services. 4x throughput, half the bandwidth. Clean protobuf schema that has been extended without breaking changes for 18 months."

SO
Sarah O.
Lead Engineer, LogiCore