Senior Custom API Development CompanyCustom API
We build production-grade APIs for B2B platforms, SaaS, and enterprise integrations. Senior engineers deliver in 8-12 weeks with fixed pricing.
IRPR is a senior custom API development company. We build RESTful, GraphQL, and gRPC APIs using Node.js, Go, Python, and .NET Core. Our team has shipped over 200 production APIs for clients in 50+ countries.
Every project ships in 8-12 weeks with a fixed price ranging from $80K to $250K. We build APIs that meet HIPAA, SOC 2, and PCI-DSS compliance from day one. You own the full source code and IP.
We are hired by CTOs who need to integrate legacy systems, founders building API-first products, enterprises migrating from monolithic architectures, and startups that need scalable B2B APIs. No junior developers, no hourly billing.
Types of software we ship.
Payment API Integration
SaaS payments with Stripe, PayPal, or Adyen. Handle recurring billing, invoicing, and multi-currency.
RESTful API Microservices
Decoupled services with Node.js or Go. Containerized with Docker and orchestrated on Kubernetes.
GraphQL API Layer
Unify multiple data sources under a single GraphQL endpoint using Apollo Server or Hasura.
Webhook System
Real-time event delivery via webhooks. Built with SendGrid, Twilio, or custom event brokers.
OAuth2 / SSO API
Secure authentication and authorization with Auth0, Okta, or custom JWT flows across multiple services.
Data Aggregation API
Aggregate data from internal databases, third-party sources, and flat files into a unified endpoint.
Realtime API
WebSocket or Server-Sent Events for live dashboards, chat, or collaborative apps using Socket.io.
File Upload and Processing API
Upload, transform, and serve files via S3 or Cloudinary with automated image resizing and CDN delivery.
We build for every business type.
Fintech
Healthcare
Ecommerce
SaaS
Logistics
Why choose a senior custom API development company?
Building APIs with mid-level talent costs more in the long run. IRPR assigns senior engineers only.
Our average engineer has 10+ years of experience. We have built 200+ APIs across fintech, healthcare, and ecommerce. Every API is designed with performance, security, and scalability in mind.
We use OpenAPI specs to design contracts before writing a single line of code. That means no integration surprises. Your team gets Postman collections, unit tests, and load test reports with every delivery.
The difference between generic dev shops and a senior API company
Not all API developers are equal. Here is how IRPR avoids the common pitfalls.
Most generic agencies assign junior or mid-level developers to save costs. They also charge hourly, which leads to scope creep and budget overruns. Many skip documentation and load testing.
IRPR works with senior engineers only. We give you a fixed price upfront, deliver in 8-12 weeks, and ship fully documented APIs with tests and monitoring.
- Junior or mid-level developers
- Hourly billing with no cap
- No formal API contract design
- Minimal documentation
- No load or security testing
- Unclear delivery timelines
- Senior engineers with 7+ years experience
- Fixed price after Roadmap phase
- API-first design with OpenAPI specs
- Full documentation: Postman, Swagger, README
- Load tested to 10K requests/min
- 8-12 week delivery with 2-week milestones
Our 4-phase process for building custom APIs
We follow a structured workflow to eliminate ambiguity and deliver on time.
Every project starts with a 2-week Discovery phase where we map your data sources, authentication needs, and performance goals. The result is a detailed API specification.
Then we build in 2-week sprints with continuous integration and automatic deployments. You see working code from week 2 onward.
What ships with every custom API project
You get more than just code. Every delivery includes everything needed to run and maintain your API.
Our checklist covers production readiness. No extra fees for documentation or deployment scripts. Everything is included in the fixed price.
- Source code in your private GitHub repo
- CI/CD pipeline with GitHub Actions or CircleCI
- Postman collection with 200+ example requests
- API documentation in Swagger/OpenAPI format
- Load testing report (artillery or k6)
- Security audit log (OWASP top 10 checks)
- Monitoring with Datadog or Prometheus
- Centralized logging with ELK stack
- Health check and readiness endpoints
- Deployment runbook for AWS or Azure
What we ship in this practice.
Fintech Payment API
Built a RESTful payment processing API for a lending platform using Node.js, Stripe, and PostgreSQL. Reduced transaction failures by 30% and handled 500K transactions per month.
Healthcare FHIR API
Developed a HIPAA-compliant FHIR API with Python and FastAPI for a telemedicine startup. Cut EHR integration time from 6 months to 8 weeks for new hospital partners.
Ecommerce Catalog GraphQL API
Created a GraphQL gateway using Apollo and DynamoDB for an online retailer. The API supports 10,000 requests per second and reduced page load time by 40%.
SaaS Billing API
Built a subscription management API in Go with Stripe Billing and Redis. The client reduced churn by 15% through real-time usage tracking and automated invoicing.
Logistics Real-Time Tracking API
Designed a WebSocket-based tracking API using Kafka and MongoDB. It processes 500K location updates per day and provides sub-second delivery for fleets.
Realtime Chat API
Developed a WebSocket chat API for a social platform using Socket.io and Redis. The system supports 1 million concurrent users with 99.9% uptime.
Why teams hire us.
Fixed price contracts
Every project gets a fixed quote after the 2-week Roadmap phase. No hourly billing, no surprise invoices, no scope creep charges. You know the total cost before development starts.
Senior engineers only
All developers have 7+ years of experience. We do not use juniors or outsource to low-cost regions. Every engineer has built production APIs for Fortune 500s and fast-growing startups.
API-first methodology
We design API contracts using OpenAPI 3.0 before writing code. This eliminates rework and ensures your frontend, mobile, and partner teams can integrate immediately.
Built for compliance
HIPAA, SOC 2, and PCI-DSS are built into our architecture from day one. We provide BAAs encrypted data, and audit logs. Over 60% of our projects have compliance requirements.
Documented and tested
Every API ships with Postman collections, automated unit tests, integration tests, and load tests. We include a security audit report and monitoring setup.
Post-launch support included
We provide 30 days of free bug fixes and monitoring after launch. You can extend with a monthly retainer for ongoing maintenance, feature additions, and infrastructure support.
Idea → Roadmap → Product → Release.
Every engagement runs through the same four-stage pipeline. Predictable by design.
Questions clients ask first.
Related services and industries.
Ready to build? Let's talk.
30-minute discovery call. No deck. We'll tell you honestly what it takes, how long, and how much.