REST, GraphQL and Webhooks
API Development Services for Your Apps and Partners
We design and build secure, documented APIs that power your web and mobile apps and give partners access to your data. Each one is versioned, so it can change without breaking the apps that depend on it.
- Spec and Docs for Every Endpoint
- OpenAPI
- Scoped Access for Apps and Partners
- OAuth 2.0
- Changes That Don't Break Clients
- Versioned
- Code and Hosting in Your Name
- Your Cloud
Signs You Need Custom API Development
Each of these slows down your product, your partners or both. A well-designed API fixes them at the source.
- Partners Waiting on Data You Export by Hand
- A Mobile App Blocked on the Backend
- An Old API Nobody Wants to Touch
- Docs That Live in One Developer's Head
- One Shared Key With Access to Everything
- Changes That Break Customer Integrations
Our API Development Services
We build new APIs and fix the ones you have, from the contract and security to the docs and hosting.
REST API Development
Resource-based endpoints with JSON, consistent errors, pagination and filtering. Our default for app backends and partner access.
GraphQL APIs
One typed schema for apps whose screens pull from many related records, with limits on query depth and cost.
Webhooks and Events
Signed events that tell partners when an order ships or a record changes, with retries and a delivery log.
Partner and Public APIs
Scoped keys or OAuth for each partner, rate limits, a sandbox and docs partners can work from on their own.
Backends for Web and Mobile Apps
The API your web or mobile app runs on, with sign-in, roles and endpoints shaped around the screens that call them.
API Modernization
A slow, insecure or undocumented API rebuilt behind the same contract, or replaced by a new version that clients move to one at a time.
API Design: REST, GraphQL or Webhooks
We choose the style by how the API will be used. REST is our default, because every language, tool and partner already knows how to call it.
GraphQL fits when your own apps need data from many related records on one screen. Webhooks push changes to clients as they happen, so partners don't have to ask every few minutes. Many APIs use REST with webhooks. If AI assistants such as Claude or ChatGPT need to reach your systems too, see our MCP server development.
Where Each Style Fits
- REST: Partner Access, Public APIs and Most Apps
- GraphQL: Your Own Apps With Data-Heavy Screens
- Webhooks: Telling Clients When Data Changes
- OpenAPI or GraphQL Schema as the Contract
Authentication, Rate Limits and Audit Logs
API security is part of the design from the first endpoint, so every app and partner reaches only what it should.
OAuth 2.0 and OpenID Connect
People sign in through your identity provider, and each token carries only the scopes that client needs.
Scoped API Keys
A separate key for each partner, limited to its own scopes, so you can rotate or revoke one without touching the rest.
Access by Role
Every endpoint checks who is calling and which records they may see, not just whether they signed in.
Every Request Validated
Every request is checked against the schema before it touches your data. Bad input gets a clear error instead of reaching the database.
Rate Limits per Client
Limits per key or per user keep one runaway script or busy partner from slowing everyone else.
Audit Log
A record of who called which endpoint and what changed, kept for your security team to review.
How Our API Development Works
You approve the API contract before we build, so your app and partner teams know exactly what is coming.
Discovery Call
We learn who will call the API, what data they need and what runs today, then send a proposal.
Contract Design
We write the OpenAPI spec: endpoints, data shapes, errors, scopes and versioning rules. You review it before we build.
Build and Demo
Short iterations with a demo of working endpoints every week, on a private test environment.
Docs and Sandbox
Reference docs from the spec, example requests and a sandbox, so client teams can try every endpoint safely.
Launch and Handover
We launch to your apps and partners, walk your team through the runbook and hand over the code and docs.
Engineering Standards
Built to Change Without Breaking Clients
Our senior engineers use AI coding tools for routine work. These habits keep that speed safe and the API stable for every app and partner that calls it.
- Code Review on Every Change
- Automated Tests for Core Workflows
- Automated Releases Through a Staging Copy
- Secrets in a Secure Vault, Never in the Code
Versioning With a Deprecation Policy
New fields and endpoints ship in place. Breaking changes get a new version, a deprecation date and a migration note.
Contract Tests
Tests check every response against the spec, so the docs and the API stay in step.
Performance and Caching
Pagination, database indexes and response caching where the data allows, planned from the first endpoint.
Monitoring From Launch Day
Error monitoring, response times and error rates by endpoint, watched from the day the API goes live.
Technologies for API Development
We build with mainstream, well-supported tools, so any capable team can maintain the API later. These are examples, not the full list, and we also work in the stack you already have.
- .NET
- C#
- Node.js
- TypeScript
- Python
- FastAPI
- Hono
- PostgreSQL
- SQL Server
- Redis
- Docker
- Microsoft Azure
- AWS
- Google Cloud
Working in Your Codebase
We work in your repository, follow your conventions and ship through your pipeline. Need engineers inside your own sprints instead of a scoped project? See staff augmentation.
- Your Repository and Branching Rules
- Your Framework and Code Style
- Your CI Pipeline and Review Process
API Development FAQ
How Much Does API Development Cost?
It depends on the number of endpoints, who calls them, the sign-in setup and the systems behind them. After a short call we send a proposal with the approach, phases, timeline and cost. A well-defined API can be quoted at a fixed price.
Which Authentication Should Our API Use?
OAuth 2.0 with OpenID Connect when people sign in through your apps, or when a partner acts on behalf of a user. OAuth client credentials or API keys for server-to-server partners. Each client gets only the scopes it needs. We recommend a setup on the discovery call, based on your clients and your identity provider.
How Do You Version an API Without Breaking Clients?
Adding a field or an endpoint doesn't break anyone, so those changes ship in the current version. Removing or renaming something needs a new version, usually in the URL (such as /v2), served beside the old one until clients move. Each client gets the deprecation date and a migration note, and contract tests catch an accidental breaking change before release.
What API Documentation Do We Get?
An OpenAPI spec, reference docs generated from it, example requests and responses for every endpoint, a sandbox with test data and a changelog. For GraphQL, the schema plays the part of the spec. Your own developers and your partners work from the same docs.
Can You Fix or Replace an API We Already Have?
Yes. We start with a review of the code, security, performance and docs. Then we recommend fixing it in place, or building a new version beside it that clients move to one at a time. If a rebuild makes more sense, we say so and explain why.
Where Is the API Hosted, and Do We Own the Code?
It runs in a cloud account in your name, such as Microsoft Azure, AWS or Google Cloud. The code lives in your repository and is yours once the project is paid in full.
Who Maintains the API After Launch?
Your team, ours or both. We hand over the code, docs and runbook at launch. If you want us to stay on for fixes, updates and new endpoints, maintenance is billed monthly with no minimum term.
Related Services
Custom Software Development
Web apps, customer portals, internal tools and dashboards built for how your business works.
Explore Custom Software DevelopmentSystem Integration
Your CRM, accounting, store and operations tools connected, so nobody types the same data twice.
Explore System IntegrationMobile App Development
One app for iPhone and Android from a single codebase, from first design to App Store and Google Play.
Explore Mobile App DevelopmentMCP Server Development
Give Claude, ChatGPT and Copilot secure access to your business systems.
Explore MCP Server DevelopmentPlan an API Your Apps and Partners Can Rely On
Tell us who will call it, what data it serves and what runs today.
- Senior Engineers
- OpenAPI Docs Included
- Code in Your Repository
What Happens Next
- Intro CallYour clients, data, systems and timeline.
- ProposalThe approach, phases, timeline and cost.
- API ContractAn OpenAPI spec you review before the build.