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API Development Services

APIs built
for what comes next.

REST, GraphQL, gRPC. OpenAPI docs. AI-native API design. Fixed price, production-ready.

★★★★★4.9/5 · 30+ clients·50+ shipped
A

Afnexis Results

Real production numbers

50+

APIs shipped

in production

<50ms

p99 latency target

production APIs

4-8 wks

to production

avg. timeline

4.9/5

client rating

30+ clients

WHAT WE BUILD

Which API do you need built?

REST API Design and Build

Resource-oriented design, OpenAPI 3.0 docs, client SDKs, versioning strategy. Built to last.

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GraphQL APIs

Schema-first design, DataLoader for N+1 prevention, subscriptions for real-time. Apollo or Pothos.

Scope this

AI and LLM APIs

Streaming endpoints for LLM responses, RAG pipelines as APIs, tool-calling endpoints for agents.

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Auth and Security Layer

OAuth 2.0, API keys, JWT, rate limiting, IP allowlisting, CORS. Every API secure from day one.

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Third-Party Integrations

Salesforce, Stripe, HubSpot, Twilio, SendGrid. We've built wrappers for every major SaaS API.

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API Performance and Monitoring

p99 latency under 50ms. Redis caching, connection pooling, load testing with k6.

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By Muhammad Aashir Tariq · CEO & Head of AI, Afnexis · Updated April 2026

REAL RESULTS

Numbers from real deployments.

<50ms

p99 latency

production APIs

50+

APIs shipped

in production

0

unversioned breaking changes

production record

4.9/5

client rating

30+ clients

"They built the API that powers our entire fintech platform. 50+ endpoints, Stripe integrated, under 40ms p99. Done in 6 weeks."

S

CTO · ShinyLoans · Fintech

HOW IT WORKS

From call to production in weeks.

1

Design

API contract first. We write the OpenAPI spec before any code. You review the interface, we build it.

2

Build

Test-driven development. Integration tests for every endpoint. No shipping without tests.

3

Document

Auto-generated docs, a Postman collection, and example responses for every endpoint.

PRICING

Fixed price. No surprises.

Ranges from 50+ real projects. Milestone billing. No retainers.

Project TypeWhat's IncludedTimelineStarting At
REST APIUp to 20 endpoints, auth, docs, tests, staging + prod3-5 weeks$15K
GraphQL APISchema design, resolvers, DataLoader, subscriptions, docs4-7 weeks$20K
AI/LLM APIStreaming endpoints, RAG integration, tool-calling, monitoring4-8 weeks$25K
Enterprise API Platform50+ endpoints, multi-tenant, versioning, rate limiting, SLAs8-16 weeks$70K

FAQ

Quick answers.

REST vs GraphQL — which should I use?

REST for most use cases. GraphQL when your clients have very different data needs (mobile vs web vs third-party) and you want to avoid over-fetching. We'll recommend the right one in scoping.

Do you write API documentation?

Yes. OpenAPI 3.0 spec, Swagger UI, and a Postman collection. For client-facing APIs we also write a getting-started guide and code examples in JavaScript and Python.

How do you handle API versioning?

URL versioning (/v1/, /v2/) for REST. We never introduce breaking changes without a new version and a deprecation timeline.

Can you build APIs that work with LLMs and AI agents?

Yes. We design APIs specifically for agent tool-calling: consistent schemas, idempotency, good error messages, and streaming where needed.

READY TO START?

Let's build your first agent.

30-min call. No pitch. We map the workflow and quote it.