API Development Services | REST, GraphQL, Webhooks | 361.dev

─── [ SERVICE_INFO: API_DEVELOPMENT ] ───

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API stands for Application Programming Interface. It's the way different software systems talk to each other. Think of an API as a waiter in a restaurant—you (the customer) don't go into the kitchen to make your food. You tell the waiter what you want, the waiter takes your order to the kitchen, and brings back your meal.

API development is the process of building these communication channels so different systems can exchange data and trigger actions.

REAL_WORLD_ANALOGY

When you use a weather app on your phone, the app doesn't store weather data. It asks a weather API: "What's the weather in New York?" The API goes to the weather service's database, retrieves the data, and sends it back to your app. All of this happens in milliseconds.

SIMPLE_EXAMPLE_-_PAYMENT_API

// Your website charges a customer via Stripe API
const charge = await stripe.charges.create({
// $20.00  amount: 2000,        
  currency: 'usd',
// Customer's card token  source: 'tok_visa',  
  description: 'Product purchase'
});

// Stripe returns confirmation:
// { id: "ch_123", status: "succeeded", paid: true }

1. Your code sent data to Stripe's API

2. Stripe processed the payment

3. Stripe sent back confirmation

4. You never handled sensitive card data

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[01]

CONNECT_EXISTING_SYSTEMS

Your business uses multiple tools: CRM (Salesforce), accounting (QuickBooks), email (Mailchimp), e-commerce (Shopify). Without APIs, you manually copy data between them. With APIs, they communicate automatically.

WITHOUT_API

New customer orders on Shopify

→ Manually export order to CSV

→ Import CSV into QuickBooks

→ Copy email to Mailchimp

→ Add customer to Salesforce CRM

20 minutes of manual work per order

WITH_API

New customer orders on Shopify

↓ [API triggers webhook]

→ Auto-creates invoice in QuickBooks

→ Adds email to Mailchimp list

→ Creates contact in Salesforce

All happens in 2 seconds, zero manual work

[02]

BUILD_CUSTOM_INTEGRATIONS

Off-the-shelf integrations don't fit your unique business logic. Custom API development lets you connect systems exactly how you need.

[03]

ENABLE_MOBILE_&_WEB_APPS

Modern apps separate frontend (what users see) from backend (where data lives). APIs connect them. Same API serves both platforms—build once, use everywhere.

[04]

MONETIZE_YOUR_DATA

If you have valuable data or functionality, build an API and charge developers to use it. This is how companies like Stripe, Twilio, and Google Maps make billions.

[05]

SCALE_EFFICIENTLY

APIs let you add features and integrations without rebuilding your entire system. Well-designed APIs grow with your business.

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Custom API development means building APIs specifically for your business needs—not using generic SaaS APIs or forcing your processes to fit someone else's system.

[SCENARIO_01]

UNIQUE_BUSINESS_LOGIC

You have processes that no off-the-shelf API handles. Example: Real estate platform with custom commission-split calculations based on agent tier, property type, and time of year.

[SCENARIO_02]

LEGACY_SYSTEM_INTEGRATION

Your company runs on a 10-year-old custom ERP system. Modern tools can't connect to it directly. Build a middleware API that translates between old and new.

[SCENARIO_03]

PERFORMANCE_REQUIREMENTS

Generic APIs are too slow for your use case. High-frequency trading, real-time gaming, IoT sensors—these need custom-built APIs optimized for millisecond response times.

[SCENARIO_04]

SECURITY_&_COMPLIANCE

You handle sensitive data (medical records, financial transactions) with strict compliance requirements (HIPAA, PCI-DSS). Custom API development ensures end-to-end encryption, audit logging, and role-based access control.

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[PHASE_01]

DISCOVERY_&_REQUIREMENTS

[2-3 days]

We identify what data needs to move between systems and what actions need to be triggered.

Questions we answer:

→ What systems need to communicate?
→ What data needs to be exchanged?
→ Who accesses the API? (internal vs external)
→ What's the expected traffic?
→ Security requirements?

[PHASE_02]

API_DESIGN

[3-5 days]

We design the API structure—endpoints, data formats, error handling. This is like creating a blueprint before construction.

Design decisions:

→ REST vs GraphQL vs WebSockets?
→ JSON vs XML data format?
→ Synchronous vs asynchronous processing?
→ Versioning strategy (v1, v2, etc.)?

[PHASE_03]

DEVELOPMENT

[2-6 weeks]

We build the API with proper error handling, validation, authentication, and performance optimization. Weekly demos showing progress.

[PHASE_04]

TESTING

[1-2 weeks]

We test every endpoint with various scenarios: valid data, invalid data, edge cases, high load.

Testing checklist:

✓ Functional testing (does it work correctly?)
✓ Security testing (can it be exploited?)
✓ Performance testing (how fast under load?)
✓ Error handling (fails gracefully?)
✓ Integration testing (works with other systems?)

[PHASE_05]

DOCUMENTATION_&_DEPLOYMENT

[3-5 days]

We write comprehensive API documentation and deploy to production with monitoring active from day one.

EXAMPLE_API_DESIGN

BASE URL: https://api.yourcompany.com/v1

Authentication:
POST   /auth/login       → Get access token
POST   /auth/refresh     → Refresh token

Orders:
GET    /orders           → List orders (paginated)
POST   /orders           → Create order
GET    /orders/:id       → Get order details
PATCH  /orders/:id       → Update order

Webhooks:
POST   /webhooks/stripe  → Payment events
POST   /webhooks/ship    → Shipping updates

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[01]

REST_APIs

REST (Representational State Transfer) is the most common API architecture. Simple, widely supported, easy to understand.

How it works:

GET /api/products/123 → Retrieve product

POST /api/products → Create product

PATCH /api/products/123 → Update product

DELETE /api/products/123 → Delete product

When to use:

→ Simple CRUD operations
→ Mobile apps that need predictable caching
→ Public APIs for third-party developers
→ Microservices communication

[02]

GRAPHQL_APIs

GraphQL lets clients request exactly the data they need—nothing more, nothing less. One request gets all needed data instead of multiple REST calls.

When to use:

→ Complex data relationships
→ Mobile apps on slow networks
→ Clients need different data shapes
→ Rapid frontend development

[03]

WEBHOOKS

Webhooks push data to your system when events happen—you don't have to poll constantly. Event-driven architecture.

How it works:

Event happens (payment succeeded)

→ Service calls your webhook URL

→ Your system processes the event

→ All in real-time, no polling

When to use:

→ Payment processing (Stripe, PayPal)
→ Real-time notifications
→ External service integration
→ Event-driven architectures

WEBHOOK_HANDLER_EXAMPLE

app.post('/api/webhooks/stripe', async (req, res) => {
// Verify signature (security critical)  
  const verified = verifyStripeSignature(req.body, req.headers);
  if (!verified) return res.status(401).send('Invalid');

  const event = req.body;

  if (event.type === 'payment_intent.succeeded') {
    await updateOrderStatus(event.data.object.id, 'paid');
    await sendReceiptEmail(event.data.object.id);
  }

  res.status(200).send('OK');
});

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[EXAMPLE_01]

PAYMENT_API_INTEGRATION

Scenario: E-commerce site needs to accept credit card payments without handling sensitive card data.

Solution: Stripe API integration with secure tokenization.

Result: PCI-compliant payment processing without storing card data.

[EXAMPLE_02]

SHOPPING_CART_API

Scenario: Mobile app and website both need shopping cart functionality.

Solution: Unified cart API with Redis for fast access.

Result: Single source of truth for cart state across all clients.

[EXAMPLE_03]

CRM_INTEGRATION_API

Scenario: Sales team uses Salesforce, but customer data lives in your custom database. Need real-time sync.

Solution: Bidirectional API integration with webhook listeners.

Result: Automatic data sync between systems.

[EXAMPLE_04]

DASHBOARD_AGGREGATION_API

Scenario: Dashboard needs data from 5 different services (analytics, social media, ads, email, support).

Solution: Backend aggregation API that calls all services in parallel and returns combined data.

Result: One fast API call instead of 5 slow ones. API keys hidden on backend.

[EXAMPLE_05]

MICROSERVICES_ARCHITECTURE

Scenario: Large application broken into smaller services (auth, orders, inventory, shipping).

Solution: API gateway that routes requests to appropriate microservices.

Result: Scalable, maintainable architecture with independent deployments.

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[SECURITY]

✓ JWT authentication with refresh tokens
✓ API key management for server-to-server
✓ OAuth 2.0 for third-party integrations
✓ Rate limiting per IP and per user
✓ Input validation and sanitization
✓ HTTPS encryption everywhere
✓ SQL injection prevention
✓ Comprehensive error handling

[PERFORMANCE]

✓ Redis caching (30x faster responses)
✓ Database query optimization
✓ Connection pooling
✓ Lazy loading and pagination
✓ CDN for static assets
✓ Horizontal scaling ready

API_METRICS_DASHBOARD

Last 30 Days

Requests:

2.1M

Avg response:

145ms

Success rate:

99.7%

P95 latency:

280ms

Errors:

0.3%

Uptime:

99.9%

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Good API documentation is the difference between developers adopting your API vs abandoning it. Every API we build includes:

INTERACTIVE_EXPLORER

Test endpoints directly in the browser. Copy cURL commands and code snippets.

CODE_EXAMPLES

Every endpoint with examples in JavaScript, Python, cURL, Ruby, PHP.

ERROR_REFERENCE

Complete error codes with descriptions and solutions.

ERROR_CODES_TABLE

Code	Description	Solution
400	Bad Request	Check request format
401	Unauthorized	Verify API key
403	Forbidden	Check permissions
404	Not Found	Verify resource ID
429	Rate Limited	Wait and retry
500	Server Error	Contact support

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Q: What is API development in simple terms?

A: API development is creating the connections that let different software systems talk to each other. Like building bridges between applications so they can share data and trigger actions.

Q: How much do API development services cost?

A: Simple REST API: $2K-5K. Medium complexity with authentication and multiple endpoints: $5K-12K. Complex systems with integrations, webhooks, and microservices: $12K-30K.

Q: How long does custom API development take?

A: Simple APIs: 1-3 weeks. Standard APIs with authentication and database: 3-6 weeks. Complex enterprise APIs: 6-12 weeks. Timeline depends on number of endpoints and integrations.

Q: Why use API instead of direct database access?

A: APIs provide security (controlled access), validation (clean data), versioning (backward compatibility), rate limiting (prevent abuse), and abstraction (hide internal complexity).

Q: What's the difference between REST API and GraphQL?

A: REST uses fixed endpoints (GET /users, POST /orders). GraphQL lets clients request exactly the data they need in one query. Use REST for simplicity, GraphQL for complex data relationships.

Q: Do you provide API documentation?

A: Yes. Every API includes complete documentation with endpoints, parameters, examples in multiple languages, error codes, and interactive testing tools.

Q: Can you integrate our system with third-party APIs?

A: Yes. We integrate with payment APIs (Stripe, PayPal), shipping APIs (FedEx, UPS), CRM APIs (Salesforce, HubSpot), and any service with a documented API.

Q: How do you secure APIs?

A: JWT authentication, API keys, OAuth 2.0, rate limiting, input validation, HTTPS encryption, SQL injection prevention, and comprehensive error handling without exposing sensitive details.

Q: What's included in API development process?

A: Requirements gathering, API design, development, testing (functional, security, performance), documentation, deployment, monitoring setup, and 2 weeks post-launch support.

Q: Can APIs handle high traffic?

A: Yes. We design APIs for scale: caching with Redis, database optimization, load balancing, CDN for static content. Our APIs handle 10,000+ requests per second.

READY_TO_BUILD_YOUR_API?

[ [ SCHEDULE_TECHNICAL_CONSULTATION ] ]

→ Free 30-minute API strategy session

→ Discuss integration requirements

→ Get architecture recommendations

→ Receive timeline and cost estimate

→ Response within 24 hours

→

We've built 30+ production APIs since 2023.

Serving 2M+ requests daily across client systems.

99.9% average uptime. <200ms response times.

REST, GraphQL, WebSockets—we build them all.

Documented, tested, production-ready.