API Development & Integration
APIs That Handle Production Load from Day One.
We design and build production-grade APIs — versioned, documented, rate-limited, and load-tested before launch. Plus integrations with 50+ third-party services.
OpenAPI 3.0 Docs
Load Tested at Launch
OAuth2 + JWT Auth
50+ Integrations Built
API Explorer
200 OK47ms
GET/users
POST/orders
PUT/products
DELETE/item
// Response
{
"id": "usr_01",
"name": "Jane Smith",
"plan": "pro",
"status": "active"
}
Rate limit: 1,000/min · Auth: Bearer token
200+
APIs Built & Integrated
<50ms
Avg. Response Time
99.99%
Uptime SLA
OAuth2
JWT & API-Key Auth
The Problem
APIs Built Fast Become APIs That Fail in Production
No versioning, no rate limits, auth bolted on later — the hidden costs compound until something breaks in front of a customer.
What gets skipped vs. what we build in from day one
APIs Built Fast
No versioning → breaking changes hurt clients
No rate limits → one bot kills your server
Auth bolted on later → security hole
Third-party failures cascade to your API
APIs Built Right
Versioned + rate-limited + authenticated from day one
Circuit breakers for third-party failures
OpenAPI spec clients can integrate against immediately
Load-tested to 3× expected peak before launch
50k
req/sec handled — zero downtime
Fintech payment processing API
8
Payment providers on one unified API
Fallback routing between providers
API Types
Every API Pattern We Build
Select an API type to see exactly how we implement it — endpoints, schema, delivery flow, or integrations.
REST API — Endpoint Reference
| Method | Endpoint | Auth | Rate Limit |
|---|---|---|---|
| GET | /users | Bearer | 1,000/min |
| POST | /orders | Bearer | 200/min |
| PUT | /products | API Key | 500/min |
| DELETE | /item | Bearer | 100/min |
OpenAPI specVersioningPaginationCachingCORS
Request Pipeline
Every Layer of the API Stack, Covered
A production API isn't just an endpoint. Every layer — from edge routing to database — needs to be designed intentionally.
Client
Web, mobile, or server
BrowseriOS/AndroidServer SDK
Edge / Gateway
Rate limit, route, cache
Cloudflare WorkersAWS API GatewayKong
Auth Middleware
Verify token, enforce RBAC
JWTOAuth2API Keys
Application Server
Business logic, transformations
Node.jsFastAPINestJSGo
Cache Layer
Sub-ms reads, reduce DB load
RedisMemcachedCDN
Database
Persistent storage
PostgreSQLMongoDBRedisS3
Our Process
Design First, Build Second
We don't write code until the API contract is agreed. Clients get an OpenAPI spec they can integrate against before a single endpoint is live — no waiting for the backend.
OpenAPI spec before any code is written
Frontend and mobile teams can start integration immediately
Auth + rate limiting before business logic
Security is structural — not added at the end
Load tested to 3× expected peak before launch
k6 test suite results delivered with every major release
01
API Design & OpenAPI Spec
We design the API contract first — endpoints, schemas, auth, error codes — and get it signed off before implementation starts.
Outcome: OpenAPI 3.0 spec, client can start integrating immediately
02
Auth & Security Layer
OAuth2, JWT, or API key auth implemented with rate limiting, IP allowlisting, and input validation before any business logic.
Outcome: security layer passing OWASP API top 10 checks
03
Build & Load Test
Endpoints built and load-tested with k6 to your expected peak traffic. No surprises in production.
Outcome: k6 load test reports, p99 latency under SLA
04
Documentation & Launch
Full OpenAPI documentation, Postman collection, developer portal, and SDK snippets delivered at launch.
Outcome: developer-ready docs + monitoring + alerting live
Your Options
Ethersofts vs. In-House vs. Offshore Agency
What gets skipped when speed is the priority — and what that costs you later.
| Feature | Ethersofts | In-House | Offshore Agency |
|---|---|---|---|
| OpenAPI documentation | Full OpenAPI 3.0 | If time allows | Basic only |
| Versioning strategy | Semantic versioning | Informal | None usually |
| Rate limiting | Yes, configurable | If remembered | Rarely |
| Auth methods | OAuth2 + JWT + API keys | Varies | Basic token |
| Load tested before launch | Yes, k6 reports | Rarely | No |
| Third-party integration expertise | 50+ connectors built | Limited to team knowledge | Ad-hoc |
Client Outcome
The Challenge
Fintech startup needed a unified payment processing API across 8 different payment providers — with automatic failover, PCI-DSS compliance, and 50k req/sec capacity.
What We Built
Unified payment API with provider abstraction, automatic failover routing, idempotency keys, webhook delivery, and full OpenAPI documentation. PCI-DSS compliant.
The Result
50k req/sec
Handled at peak load
99.999%
Uptime — 5 nines
$18M+
Processed in first quarter
Need an API built to handle real production load? Talk to an engineer this week.
“The API handles 50k requests per second without breaking a sweat. Every endpoint documented, every edge case handled, and the OpenAPI spec made our frontend integration trivial.”
FAQ
Questions we get all the time
If yours is not here, reach out. We respond within 24 hours with a real answer from an engineer — not a sales pitch.
REST for most APIs — simpler clients, easier caching, better CDN support, and every developer knows it. GraphQL makes sense when you have many different clients with different data needs (mobile vs web vs third party), or when your data has complex nested relationships. We recommend based on your client diversity, not trend.
We use URL-based versioning (/v1/, /v2/) for public APIs and header-based for internal ones. Every versioning strategy includes a deprecation policy — clients get at least 6 months notice before a version is sunset, with migration guides provided.
OAuth2 with refresh tokens for user-scoped APIs, JWT with short expiry + refresh rotation for session management, and API keys with scopes and rotation policies for machine-to-machine. We implement the right combination for your threat model — not just whatever is fastest to build.
Rate limiting is applied per IP, per API key, and per user — with separate limits for read and write operations. We use Redis sliding window counters for accuracy under burst traffic. Requests exceeding limits get a 429 with a Retry-After header. Alerts fire before limits are hit.
Yes — we've built integrations with 50+ services including Stripe, Twilio, SendGrid, HubSpot, Salesforce, Shopify, Plaid, AWS services, Google Workspace, and more. Third-party failures are handled with circuit breakers and graceful degradation so your API keeps working even when a dependency is down.
A focused REST or GraphQL API with auth, documentation, and rate limiting typically takes 4–8 weeks. Complex multi-provider integrations or APIs requiring 50k+ req/sec throughput run 8–14 weeks. Because we design the OpenAPI contract first, your frontend and mobile teams can start integrating in week one — they don't wait for the backend to finish.
Every API ships with a full OpenAPI 3.0 specification, an interactive developer portal, a ready-to-import Postman collection, and SDK code snippets in your team's languages. Documentation is generated from the spec, so it never drifts out of sync with the actual endpoints as the API evolves.
API Development & Integration
APIs That Work at Scale — From the First Request
Don't build an API wrapper that breaks in production. Let Ethersofts build an API designed for the traffic you'll have — not just the traffic you have today.
Free consultation24-hour responseNDA on request
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