API DEVELOPMENT

Your Custom API, Built to Scale, From $5,000

Production-grade APIs deployed on our global edge network. REST, GraphQL, WebSocket, and webhook integrations — designed, built, and shipped for real business traffic in as little as 1 week.

Custom API development services for businesses that need production-grade APIs built on our global edge network. Starting at $5,000 for a standard REST API, with complex integrations from $10,000 to $50,000+. Every API ships with full documentation, authentication, error handling, and edge deployment — ready to serve real traffic from day one.

As a specialized API development company, we focus exclusively on building APIs that power web applications, mobile backends, data platforms, and AI-driven products. Our web API development practice uses TypeScript, Hono, and a global edge network to deliver sub-50ms response times globally.

What Your Project Includes

Custom API Development Services

From simple data APIs to complex real-time systems, we deliver production-ready APIs for every use case. Each service includes full documentation, testing, and deployment.

🔗

REST APIs

Resource-oriented APIs built with clean URL structures, proper HTTP semantics, and versioned endpoints. The backbone of modern web and mobile applications.

  • OpenAPI 3.1 specification with interactive documentation
  • CRUD operations with pagination, filtering, and sorting
  • Versioned endpoints (/v1/, /v2/) with deprecation strategy
  • Rate limiting, caching headers, and response compression

GraphQL APIs

Flexible query APIs that let clients request exactly the data they need. Reduced over-fetching, strong typing, and a single endpoint for complex data requirements.

  • Strongly typed schema with auto-generated TypeScript types
  • Query, mutation, and subscription support
  • DataLoader pattern for N+1 query prevention
  • Query complexity analysis and depth limiting

WebSocket APIs

Real-time bidirectional communication for chat applications, live dashboards, collaborative editing tools, and streaming data services with sub-millisecond message delivery.

  • Persistent connections with automatic reconnection logic
  • Room-based messaging and presence tracking
  • Message batching and backpressure handling
📨

Webhook Integrations

Event-driven webhook systems for payment notifications, CI/CD pipeline triggers, data synchronization between systems, and third-party service automation.

  • Webhook signature verification and replay protection
  • Retry logic with exponential backoff for failed deliveries
  • Event logging and delivery status tracking dashboard
  • Configurable event subscriptions per consumer
Technology

Our API Tech Stack

We build on modern, proven technologies that deliver edge performance, type safety, and long-term maintainability. Every tool in our stack is chosen for production reliability.

☁️

Edge Runtime

Deployed to 300+ cities worldwide. Sub-50ms cold starts, zero server management, and automatic scaling from zero to millions of requests.

🔥

Hono

Ultra-fast, lightweight web framework built for edge runtimes. Middleware, routing, and developer experience that rivals Express without the bloat.

📘

TypeScript

Full type safety across your entire API — request validation, response types, database queries, and shared types with your frontend team.

🗄️

D1

SQLite-compatible edge database. ACID transactions, familiar SQL syntax, and automatic read replication for global performance.

🔄

Stateful Compute

Stateful compute at the edge. Perfect for real-time collaboration, WebSocket rooms, rate limiting counters, and distributed coordination.

📦

R2

S3-compatible object storage with zero egress fees. Store files, images, documents, and large datasets without worrying about bandwidth costs.

🤖

Edge AI

Run AI inference at the edge — LLMs, embeddings, image classification. Build AI-ready APIs without managing GPU infrastructure.

How It Works

From Idea to Production in 5 Steps

A proven development process that delivers results on time and on budget. Every phase has a clear deliverable and your sign-off before we move forward.

1

Discovery — 1–2 days

We learn your business goals, map existing systems, define data models, and identify all integration requirements. This phase produces a detailed requirements document covering every endpoint, authentication strategy, and data flow your API needs to support. We also identify potential risks and outline mitigation strategies before any code is written.

2

Architecture — 2–3 days

We design the complete API architecture: endpoint structure, database schemas, caching layers, error handling patterns, and deployment strategy. You receive an OpenAPI specification and architecture document for review and approval. We plan for scale from the start — your API won't need a rewrite when traffic grows.

3

Development — 1–4 weeks

Our engineers build your API in TypeScript with Hono on our global edge network. We implement every endpoint, middleware layer, authentication flow, and third-party integration defined in the architecture. We deliver working increments every few days so you can test and provide feedback throughout the build phase — no surprises at delivery.

4

Testing — 3–5 days

Thorough testing across every layer: unit tests for business logic, integration tests for API endpoints, load tests for performance under traffic, and security scans for vulnerability detection. We verify every endpoint against the OpenAPI specification and test real-world edge cases — malformed requests, authentication failures, rate limit behavior, and concurrent access patterns.

5

Deployment — 1 day

Production deployment to a global edge network with CI/CD pipelines, monitoring dashboards, uptime alerting, and operational runbooks. We do a final smoke test against production traffic, verify all monitoring is active, and conduct a handoff session where we walk your team through the architecture, documentation, and operational procedures.

Pricing

Transparent Custom API Development Pricing

No hidden fees. No surprise invoices. Every tier includes documentation, testing, and production deployment. Choose the scope that fits your project.

Starter
$5,000
Basic API with core endpoints and documentation
  • 3–5 REST endpoints with full CRUD
  • OpenAPI 3.1 specification
  • API key authentication
  • Edge deployment
  • Interactive API documentation
  • Basic error handling and logging
  • 1–2 weeks delivery
Get Started 🔥
Enterprise
$50,000+
Full API platform with microservices architecture
  • Unlimited endpoints and resources
  • Microservices or multi-service architecture
  • AI-ready endpoints and MCP server integration
  • Custom RBAC and multi-tenant support
  • Real-time monitoring dashboard
  • Compliance review (SOC2, HIPAA, GDPR)
  • Dedicated support SLA and on-call engineering
  • Full documentation, runbooks, and knowledge transfer
  • 2–4 months delivery
Contact Us 🔥

Need a different scope? See our detailed cost guide or get a custom quote.

FAQ

Custom API Development FAQ

Common questions about our custom API development services, pricing, timelines, and technology choices. Can't find your answer? Ask us directly.

Custom API development is the process of designing, building, and deploying APIs tailored to your exact business requirements — not off-the-shelf solutions. At Possibility Engineering, we build production-grade APIs on our global edge network using TypeScript and Hono, with full OpenAPI docs, auth, error handling, and monitoring from day one.
Starter APIs with 3–5 endpoints start at $5,000. Professional APIs with auth, integrations, and real-time features range from $10,000–$30,000. Enterprise platforms start at $50,000. We provide transparent quotes before work begins — no hidden fees. See our cost guide for details.
Starter APIs take 1–2 weeks. Professional APIs with multiple resources and integrations take 3–6 weeks. Enterprise platforms take 2–4 months. We deliver working increments throughout development so you can track progress and provide feedback.
TypeScript on our global edge network with Hono framework. Edge SQL databases, stateful edge computing, edge object storage, and edge caching. Auth via JWT, OAuth2, or API keys. AI capabilities via edge inference. Everything deploys through automated CI/CD pipelines.
Yes. Support plans start at $500/month covering bug fixes, monitoring, dependency updates, security patches, and incremental features. Includes guaranteed response times (4 hours critical, 24 hours standard). Enterprise clients get dedicated SLAs with on-call engineering.
Every API ships with versioned endpoints (/v1/, /v2/) and a clear deprecation strategy. Maintenance includes automated dependency updates, performance monitoring dashboards, alerting, and adapting integrations when third-party APIs change.
Security is built into every layer: input validation, proper auth with token rotation, rate limiting, HTTPS enforcement, scoped CORS, automated security scans, OWASP Top 10 testing, and request logging with audit trails. Enterprise projects get RBAC and compliance support (SOC2, HIPAA, GDPR).
GET STARTED

Ready to Build Your Custom API?

Tell us what you need. We'll respond within 24 hours with a clear plan, honest pricing, and a realistic timeline. No pressure, no commitment — just a straightforward conversation about your API project.

Get Your API Built — Free Consultation
Talk to Us →