01
Discovery
Understand use cases, consumers, data sources, volumes, security needs and the third-party systems involved.
API Development and Integration Services
PerfectionGeeks designs and builds custom REST, GraphQL, gRPC and webhook APIs, and integrates third-party services such as payment gateways, CRMs, ERPs, logistics, maps, messaging and AI models into your web and mobile apps. Every API ships with OAuth 2.0 or token security, rate limiting, automated tests, monitoring and OpenAPI documentation. A single third-party integration typically costs $3,000–$15,000; a custom API for an app or partner platform $15,000–$60,000; and an enterprise API platform $60,000–$200,000+.
12+Years Building Software
200+Projects Delivered
4.9/5Clutch Rating (45+ Reviews)
- We build custom APIs (REST, GraphQL, gRPC, webhooks) and integrate third-party APIs into web, mobile and back-end systems.
- Security comes first: OAuth 2.0 and OpenID Connect, encryption, rate limiting and OWASP API Security Top 10 checks.
- Every API includes OpenAPI documentation, automated tests, versioning and monitoring.
- Typical cost: $3K–$15K per integration, $15K–$60K for a custom API, $60K–$200K+ for an enterprise API platform.
- We also fix and modernise existing APIs: slow endpoints, security gaps, missing docs and legacy SOAP services.
What Is API Development and Integration?
What Is API Development and Integration?
Our API Development and Integration Services
Custom API Development
REST, GraphQL and gRPC APIs designed around your data and use cases, with clear resources, versioning and error handling.
Mobile App Back-End APIs
Fast, secure APIs for iOS, Android, Flutter and React Native apps, with authentication, push notifications, offline sync and file uploads.
Third-Party API Integration
Payment gateways, CRMs, ERPs, accounting, logistics, maps, messaging, social login and analytics connected to your product.
Public and Partner APIs
APIs for customers and partners, with developer portals, API keys, usage plans, sandbox environments and documentation.
Enterprise and System Integration
Connect ERP, CRM, HR, finance and legacy systems through APIs, middleware, message queues and event streams.
AI and LLM API Integration
Add OpenAI, Anthropic Claude, Google Gemini or open-source models to your product for chat, search, document processing and agents.
API Modernisation
Upgrade SOAP or legacy APIs to REST or GraphQL, split monolith endpoints, improve speed and close security gaps.
API Testing, Documentation and Support
Automated tests, OpenAPI documentation, monitoring, uptime alerts and ongoing maintenance.
Types of APIs We Build
.
| API type | Best for | Notes |
|---|---|---|
| REST | Most web and mobile apps, public APIs | Simple, cacheable, widely supported; documented with OpenAPI |
| GraphQL | Apps that need flexible data from many sources | Clients request exactly the fields they need; fewer round trips |
| gRPC | Fast service-to-service communication | Binary protocol, strongly typed, ideal inside microservices |
| Webhooks | Real-time notifications to other systems | Push events such as "payment succeeded" instead of polling |
| WebSockets and SSE | Live chat, tracking, dashboards, streaming AI responses | Two-way or server-push real-time data |
| SOAP | Legacy banking, government and enterprise systems | We integrate with and modernise SOAP services |
By Audience: Private, Partner, Public and Composite APIs
Private (internal) APIs
Connect your own apps, services and teams.
Partner APIs
Shared with selected partners under contracts and keys.
Public (open) APIs
Available to external developers, often with usage-based pricing.
Composite APIs
Combine several calls into one to simplify clients and improve speed.
Third-Party Integrations We Deliver
.
| Category | Examples |
|---|---|
| Payments | Stripe, PayPal, Razorpay, Adyen, Braintree, Apple Pay, Google Pay, UPI |
| CRM and marketing | Salesforce, HubSpot, Zoho, Mailchimp, Klaviyo |
| ERP and accounting | SAP, Microsoft Dynamics 365, Odoo, NetSuite, QuickBooks, Xero, Tally |
| eCommerce | Shopify, WooCommerce, Magento, Amazon and marketplace APIs |
| Communication | Twilio, SendGrid, WhatsApp Business API, Firebase Cloud Messaging |
| Maps and logistics | Google Maps, Mapbox, Shiprocket, FedEx, DHL, UPS |
| Identity and KYC | Auth0, Okta, Firebase Auth, Onfido, DigiLocker |
| Healthcare | HL7 FHIR, EHR systems, telehealth video |
| Banking and fintech | Plaid, open banking APIs, account aggregator, card issuing |
| AI | OpenAI, Anthropic, Google Gemini, AWS Bedrock, Hugging Face |
| Cloud services | AWS, Azure, Google Cloud APIs |
API Security Built In
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| Control | What we implement |
|---|---|
| Authentication | OAuth 2.0 and OpenID Connect, short-lived JWTs, API keys for server-to-server, mutual TLS where needed |
| Authorisation | Role- and scope-based access checked on every request, object-level checks to stop data leaks |
| Encryption | TLS 1.2+ in transit, encryption at rest for sensitive data, secrets in a vault |
| Input validation | Strict schemas, size limits and safe handling of uploads |
| Rate limiting and throttling | Per-client limits, quotas and protection against abuse and traffic spikes |
| API gateway | AWS API Gateway, Azure API Management, Kong or Apigee for routing, keys and policies |
| Monitoring and audit | Request logs, anomaly alerts and audit trails without logging sensitive data |
| Testing | Checks against the OWASP API Security Top 10, plus penetration testing for high-risk APIs |
Our API Quality Standards
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Design first
We agree the API contract in OpenAPI or a GraphQL schema before coding, so front-end and partner teams can start in parallel.
Consistent design
Clear resource names, standard HTTP status codes, pagination, filtering and a consistent error format.
Versioning
A clear versioning and deprecation policy so changes never break existing clients.
Performance
Caching, efficient queries, pagination and response-time targets (for example under 200 ms for common reads).
Reliability
Timeouts, retries with backoff, idempotency keys for payments and orders, and queues for slow work.
Documentation
Interactive OpenAPI (Swagger) docs, examples, Postman collections and changelogs.
Automated testing
Unit, integration, contract and load tests in CI/CD.
Observability
Logs, metrics, tracing and uptime alerts from day one.
API Development Tech Stack
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| Layer | Technologies |
|---|---|
| Languages and frameworks | Node.js (NestJS, Express, Fastify), Python (FastAPI, Django REST Framework), Java (Spring Boot), .NET, Go, PHP (Laravel) |
| API styles | REST, GraphQL (Apollo), gRPC, webhooks, WebSockets |
| Databases | PostgreSQL, MySQL, MongoDB, Redis, Elasticsearch |
| Messaging | Kafka, RabbitMQ, AWS SQS, Google Pub/Sub |
| Gateways and management | AWS API Gateway, Azure API Management, Kong, Apigee |
| Documentation and testing | OpenAPI, Swagger UI, Postman, Pact, k6, Jest, pytest |
| Cloud and DevOps | AWS, Azure, Google Cloud, Docker, Kubernetes, serverless functions, GitHub Actions |
| Monitoring | OpenTelemetry, Datadog, Grafana, Prometheus, Sentry |
How Much Does API Development and Integration Cost?
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| Scope | What is included | Cost (USD) | Timeline |
|---|---|---|---|
| Single third-party integration | One service (for example a payment gateway, CRM or shipping API), error handling, tests | $3,000–$15,000 | 1–4 weeks |
| Custom API for an app | 20–60 endpoints, authentication, database, documentation, tests, deployment | $15,000–$60,000 | 1–3 months |
| Integration platform or middleware | Several systems synced (ERP, CRM, eCommerce, accounting), queues, monitoring | $30,000–$100,000 | 2–5 months |
| Enterprise or public API platform | API gateway, developer portal, usage plans, multiple versions, high availability, compliance | $60,000–$200,000+ | 4–9 months |
Our API Development Process
02
API design
Define resources, endpoints or schema, authentication, error format and versioning in an OpenAPI or GraphQL contract you approve.
03
Development
Build in short sprints with code reviews, automated tests and a working sandbox early on.
04
Integration
Connect third-party services and internal systems, with retries, idempotency and webhook handling.
05
Testing and security review
Functional, contract, load and security testing, including OWASP API Top 10 checks.
06
Documentation and deployment
Publish interactive docs and deploy through CI/CD to your cloud, behind an API gateway.
Common API Integration Challenges and How We Solve Them
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| Challenge | How we solve it |
|---|---|
| Poor or outdated third-party docs | Sandbox testing, contract tests and direct contact with the provider's support |
| Rate limits and timeouts | Queues, caching, batching and retries with backoff |
| Data mismatches between systems | Clear field mapping, validation and reconciliation reports |
| Breaking changes by providers | Version pinning, change monitoring and automated alerts |
| Duplicate payments or orders | Idempotency keys and transaction logs |
| Security gaps | Gateway policies, scoped tokens, secret rotation and regular audits |
| Slow mobile apps | Lean payloads, pagination, GraphQL or backend-for-frontend endpoints |
Industries We Build APIs For
.
| Industry | Typical API work |
|---|---|
| Fintech and banking | Payments, open banking, KYC, card and wallet APIs, PCI DSS compliance |
| Healthcare | HL7 FHIR APIs, EHR integration, telehealth, HIPAA compliance |
| eCommerce and retail | Catalogue, inventory, order and marketplace sync, payment and shipping |
| Logistics | Tracking, route optimisation, carrier and warehouse integration |
| SaaS | Public APIs, webhooks, integrations marketplace, usage-based billing |
| Education | LMS, video, payment and student information system integration |
| Travel and hospitality | Booking engines, GDS, channel managers and payment APIs |
| Real estate | Listings, CRM, maps and payment integration |
iOS and Mobile API Integration
iOS and Mobile API Integration
Why Choose PerfectionGeeks for API Development
Design-first APIs
An agreed contract before code, so teams work in parallel and nothing is lost in translation.
Security by default
OAuth 2.0, gateways, rate limits and OWASP checks on every project.
Documentation you can hand over
OpenAPI docs, Postman collections and runbooks.
Integration experience
Payments, CRM, ERP, logistics, healthcare and AI APIs.
Full-stack team
We can build the web and mobile apps that use your APIs too.
Proven delivery
12+ years, 200+ projects and a 4.9/5 rating on Clutch from 45+ reviews.
Related Reading
Related Reading
Discuss Your API or Integration Project
Tell us which systems you need to connect or what your API must do. Within 2 business days we will send a recommended approach, a cost estimate and a timeline, under an NDA.
Client Testimonials
PerfectionGeeks provided excellent service from start to finish. Their team was professional, easy to work with, and delivered exactly what we needed on time. We’re very pleased with the outcome and would gladly recommend them to others.
Thanaboon Mingkaew
CEO, SMART IOT
We partnered with PerfectionGeeks for a custom accounting automation software, and the experience was excellent. Their team delivered a high-quality solution that streamlined our operations and improved efficiency. Professional, skilled, and reliable — we’re already working with them on another project.
Saarthak Gupta
Founder, Ceos Accounting Services
As COO of TRP Construction Management, I’m proud of our growth from 300 to 16,000+ SKUs and 4,000+ vendors since 2022. Thanks to Shrey Bhardwaj and Perfection Geeks for delivering scalable, future-ready technology solutions that transformed our vision into a seamless pan-India platform. Highly recommended technology partner.
Mayank Pathak
COO, TRP Construction Management
PerfectionGeeks Technologies transformed our vision into reality with innovative technology solutions. Their professionalism, timely delivery, transparent communication, and commitment to quality made the entire collaboration smooth, reliable, and highly satisfying.
Armaan
Cofounder, Kzminer
I highly recommend PerfectionGeeks Technologies for mobile and web development services. Their expertise, dedication, creative ideas, and customer-focused approach helped our business achieve impressive digital growth successfully.
Chetna
Founder CEO , Klicked
Choosing PerfectionGeeks Technologies was the best decision for our company. Their skilled developers created a user-friendly platform, provided constant assistance, and ensured exceptional performance beyond our expectations every step.
Mark
CTO, IMSMART
Working with PerfectionGeeks Technologies was an excellent experience. Their team delivered our project on time with outstanding quality, smooth communication, innovative solutions, and professional support throughout the entire development process.
Naveen
Founder Director , Way2Kart
PerfectionGeeks Technologies delivered a smooth, professional experience with excellent communication and technical expertise. Their team understood project requirements clearly, provided timely updates, and ensured high-quality results that exceeded expectations.
Srinivasa Mothay
CTO, Sethu Fishries
PerfectionGeeks Technologies impressed with their innovative solutions, responsive support, and commitment to quality. The team handled every detail professionally, delivered on time, and created a seamless experience from start to finish.
Mervin
Cofounder & CTO, Clover Infinity
Frequently Asked Questions
What is API development?
API development is designing, building, testing and documenting the interfaces that let software systems exchange data and trigger actions, such as the back end behind a mobile app or a platform's partner API.
What is API integration?
API integration is connecting your software to another system's API, such as a payment gateway, CRM or shipping provider, so data moves automatically between them.
How much does API development cost?
A single third-party integration typically costs $3,000–$15,000, a custom API for an app $15,000–$60,000, an integration platform $30,000–$100,000 and an enterprise or public API platform $60,000–$200,000 or more.
How long does it take to build an API?
A single integration takes 1–4 weeks, a custom app API 1–3 months and an enterprise API platform 4–9 months.
Should I use REST or GraphQL?
REST suits most public APIs and simple apps because it is easy to cache and widely understood. GraphQL suits apps that combine data from many sources and need flexible queries, such as complex mobile and web front ends.
How do you secure APIs?
With OAuth 2.0 or OpenID Connect, scoped tokens, TLS encryption, input validation, rate limiting, an API gateway, logging and testing against the OWASP API Security Top 10.
Do you provide API documentation?
Yes. Every API comes with interactive OpenAPI (Swagger) or GraphQL documentation, examples, Postman collections and a changelog.
Can you integrate payment gateways and CRMs into our app?
Yes. We integrate Stripe, PayPal, Razorpay, Apple Pay, Google Pay, Salesforce, HubSpot, Zoho and many other services into web and mobile apps.
Can you connect our ERP with our eCommerce store and CRM?
Yes. We build integrations and middleware that sync products, stock, orders, customers and invoices between ERP, CRM and eCommerce platforms.
Do you build APIs for iOS and Android apps?
Yes. We build mobile-ready APIs with secure login, push notifications, offline sync and small payloads, and integrate them with native, Flutter and React Native apps.
Can you fix or modernise our existing APIs?
Yes. We audit slow or insecure APIs, add documentation and tests, introduce versioning and gateways, and migrate SOAP or legacy services to REST or GraphQL.
Do you maintain APIs after launch?
Yes. We provide monitoring, uptime alerts, performance tuning, security updates and handling of third-party API changes under monthly support plans.