API & Integration Specialists

Connect Everything.
API Development & Integration

Custom REST, GraphQL and gRPC APIs engineered for reliability, security and scale. We connect your platforms, automate data flows and eliminate the silos slowing your product down.

REST & GraphQL gRPC & WebSocket 200+ Integrations OAuth 2.0 / JWT API Gateway
Mobile App
Web Client
AWS / GCP
Database
3rd-Party
Webhooks
200+
APIs Built & Integrated
<80ms
Average API Latency
99.99%
API Uptime SLA
10M+
Daily API Calls Served
What We Build

End-to-End API Services

From greenfield API design to complex enterprise integrations — we architect, build, document and maintain your API layer.

Custom REST API Development
Production-grade RESTful APIs with OpenAPI 3.0 documentation, versioning strategy, rate limiting, and full test coverage. Built to scale from day one.
OpenAPIVersioningRate Limiting
GraphQL API Development
Flexible GraphQL APIs that let clients fetch exactly what they need. Schema-first design, real-time subscriptions, and DataLoader optimisation to eliminate N+1 queries.
Schema DesignSubscriptionsCaching
Third-Party API Integration
Seamlessly integrate payment gateways, CRMs, ERPs, maps, SMS, email, and any SaaS platform into your product. We handle auth flows, error handling, and retries.
StripeSalesforceTwilio
API Gateway & Management
Centralised API gateway with traffic routing, authentication, caching, analytics and developer portal. AWS API Gateway, Kong, and custom solutions.
KongAWS GatewayAuth
Webhook & Event-Driven APIs
Real-time webhook systems and event-driven architectures using message queues (Kafka, RabbitMQ, SQS) for reliable, decoupled service communication at scale.
KafkaRabbitMQSQS
API Security & Compliance
End-to-end API security — OAuth 2.0, JWT, API key management, HTTPS enforcement, input validation, DDoS protection, and OWASP API Top 10 compliance.
OAuth 2.0JWTOWASP
Technology Stack

APIs Built With Best-in-Class Tools

Node.js Python FastAPI Java Spring Boot Go (Golang) GraphQL gRPC AWS API Gateway Azure APIM Node.js Python FastAPI Java Spring Boot
Kong Gateway Redis Cache Kafka RabbitMQ AWS SQS / SNS Swagger / OpenAPI Postman Kong Gateway Redis Cache Kafka
API Engineering Standards

APIs Built for Production Scale

Every API we build follows enterprise-grade engineering standards — documented, versioned, secured, and monitored from the moment it ships.

Auto-Generated Documentation
OpenAPI / Swagger docs generated from code — always in sync. Developer portal with interactive try-it-now sandbox for every endpoint.
Observability & Monitoring
Every API ships with structured logging, distributed tracing (Jaeger/Zipkin), and real-time alerting on latency, error rates, and throughput.
Backward-Compatible Versioning
URI versioning, deprecation headers, and migration guides ensure your API consumers are never broken by upstream changes.
🔑
OAuth 2.0 & JWT Auth
Industry-standard authentication with refresh token rotation, scope-based access, and PKCE for public clients.
Sub-100ms Response
Optimised query plans, Redis caching, connection pooling and CDN edge caching ensure blazing-fast API responses.
🔄
Idempotent Design
Safe retry logic, idempotency keys, and circuit breaker patterns prevent duplicate operations and cascade failures.
📈
Horizontal Scaling
Stateless API design with containerised deployments means your API auto-scales to handle 10× traffic spikes instantly.
🧪
Contract Testing
Pact-based consumer-driven contract tests catch breaking changes before they reach production — CI/CD integrated.
🌍
Multi-Region Deployment
Global API routing with latency-based DNS, regional failover, and active-active replication for zero-downtime.
Why Appther

Why Teams Choose Appther for APIs

We don't just write endpoints — we architect integration layers that become the backbone of your product.

01
Documentation-First
We design the API contract before a single line of code — ensuring consumer teams can work in parallel and requirements are clear from day one.
02
Security by Default
OWASP API Top 10 review on every build. Automated penetration testing, secrets scanning, and input sanitisation are non-negotiable.
03
2-Week API Delivery
Focused sprint cycles with a working, tested API in 2 weeks. No months-long waterfall projects — you see results fast.
04
Built to Scale
APIs designed to handle 10× current traffic without re-architecture. Horizontal scaling, caching, and async processing built in from the start.
05
SDK Generation
We generate typed client SDKs in JavaScript, Python, Go and Java from your OpenAPI spec — so your consumers integrate in hours, not weeks.
06
Ongoing Support
Dedicated engineers on call for API incidents. SLA-backed response times, proactive monitoring, and versioned upgrade paths.
Our Process

From Contract to Production API

A proven 5-step API delivery process that ships fast without cutting corners.

1
API Design
Define resources, endpoints, data models, and auth strategy using OpenAPI-first design.
2
Security Architecture
Design auth flows (OAuth 2.0, API keys), rate limiting, and OWASP compliance plan.
3
Build & Test
Develop with TDD — unit, integration, and contract tests. Mocked servers for parallel consumer development.
4
Deploy & Monitor
CI/CD pipeline deployment with blue-green releases, distributed tracing, and real-time dashboards.
5
Document & Handoff
Developer portal, SDK generation, runbooks, and on-call handoff to your team.
Use Cases

What Our APIs Power

From mobile backends to enterprise middleware — APIs we build are the backbone of real products.

📱
Mobile App Backend
High-performance REST/GraphQL backends powering iOS and Android apps with real-time sync.
💳
Payment Integration
Stripe, PayPal, Razorpay and custom payment gateway integrations with webhook reconciliation.
🏢
ERP / CRM Sync
Bidirectional data sync between Salesforce, SAP, HubSpot and your internal systems via middleware APIs.
🤖
AI Model APIs
Expose ML models and LLMs as managed APIs with input validation, rate limiting, and usage billing.
🛒
E-Commerce Platform
Inventory, orders, shipping, and marketplace APIs connecting storefronts to fulfilment and logistics.
🏥
Healthcare HL7 / FHIR
HIPAA-compliant FHIR R4 APIs connecting EHR, lab, and patient portal systems securely.
📊
Data Pipeline APIs
High-throughput ingestion APIs feeding data lakes and analytics platforms with schema validation.
🔔
Notification & Webhook Hub
Multi-channel notification APIs and webhook delivery systems with guaranteed at-least-once delivery.
FAQ

Frequently Asked Questions

REST vs GraphQL — which should I choose?

REST is ideal for simple CRUD operations, public APIs, and teams that value convention. GraphQL shines when clients need flexible data fetching, you have multiple front-end consumers with different data needs, or you want to reduce over-fetching. We'll recommend the right approach after understanding your use case — sometimes the answer is both.

How long does API development take?

A focused API module typically takes 1–2 weeks. A complete product API layer with auth, versioning, documentation, and monitoring takes 4–6 weeks. Integrations with third-party services typically add 1–3 days per integration depending on API quality. We provide a detailed estimate after reviewing your requirements.

Do you provide API documentation?

Yes — every API we build includes auto-generated OpenAPI 3.0 / Swagger documentation with live examples, a developer sandbox for testing, and written integration guides. We also offer optional developer portal setup on Readme.io or similar platforms.

How do you secure APIs against attacks?

We implement OAuth 2.0 / JWT authentication, rate limiting, IP allowlisting, input validation and sanitisation, HTTPS enforcement, and run automated scans against the OWASP API Security Top 10 on every release. Security is not an afterthought — it is part of the architecture from day one.

Can you integrate with our existing legacy systems?

Yes. We specialise in building adapter layers and middleware that expose legacy systems (SOAP, FTP, database-direct) as modern REST or GraphQL APIs without requiring you to replace the underlying system. This is one of the most common engagement types we handle.

What is the cost of API development?

API development at Appther starts from $5,000 for a focused integration and ranges to $50,000+ for a complete API platform with gateway, docs, SDKs and monitoring. We quote fixed-price after reviewing your scope — no hourly billing surprises.

Start Building

Ready to Connect Your Entire Stack?

Get a free API architecture review. We'll map your integration landscape and propose a clean, scalable solution — no commitment required.

Free NDA Signing 24-hr Response Fixed-Price Quotes 90-Day Warranty