# API development: secure, documented and built to scale

> Custom REST and GraphQL API development, third-party API integrations, gateways and documentation. Secure-by-design APIs from NPCoding.

Source: https://npcoding.ca/services/api-development/

An API is the silent engine behind your digital products. We build APIs that are secure and developer-friendly, with contract tests, clear documentation and low latency, and use AI to keep the schema, code and docs in step.

Part of the [Software & App Development](https://npcoding.ca/services/ai-software-engineering/) capability.

## Overview

We design with a security-first mindset: authentication and authorization, rate limiting, input validation and encryption in transit are standard, not add-ons. Using REST and GraphQL standards, we create flexible architectures that grow with you, and we emphasize clean code and automated testing so complex integrations become seamless experiences.

Beyond building your own APIs, we integrate third-party ones every day — from a real-time weather feed on a trilingual port website to the institutional systems behind a university research portal and a verse database powering an online learning community.

## Is this the right service?

Choose API Development when:

- You're designing an API that others will consume: partners, mobile apps or customers
- The contract, versioning, documentation and developer experience matter as much as the endpoints
- You need authentication, rate limits and usage monitoring per consumer

Consider instead:

- [Enterprise Application Integration](https://npcoding.ca/services/enterprise-application-integration/) when you need existing business systems to exchange data reliably, rather than a new API product

## What's included in API development

- **REST & GraphQL API design:** Contract-first APIs with consistent resources, pagination, errors and versioning.
- **API security & gateways:** OAuth 2.0 / OpenID Connect, API keys, rate limiting and gateways that protect your data.
- **Third-party integrations:** Payments, shipping, CRM, maps, weather, social and institutional systems — connected reliably.
- **Webhooks & event-driven flows:** Real-time notifications and asynchronous processing that keep systems in sync.
- **Documentation & developer portals:** OpenAPI specifications, examples and onboarding guides your partners will actually use.
- **Performance & monitoring:** Caching, load testing and observability so your API stays fast under pressure.

## The contract is agreed before the code.

An illustrative excerpt from an OpenAPI contract. Resources, errors and versions are decided up front, and the contract tests come from the same file. (Illustrative example.)

`orders-api.yaml (excerpt)`:

```
openapi: 3.1.0
info:
  title: Orders API
  version: 2.1.0
paths:
  /v2/orders/{orderId}:
    get:
      security: [{ oauth2: [orders.read] }]
      responses:
        "200": { $ref: "#/components/responses/Order" }
        "404": { $ref: "#/components/responses/NotFound" }
        "429": { $ref: "#/components/responses/RateLimited" }
```

- Errors and rate limits are part of the contract, not an afterthought
- Scopes say exactly what each consumer may read or change
- Breaking changes get a new version and a deprecation window
- Contract tests run on every change, so consumers aren't the first to notice

## How AI assists API development.

Where AI helps:

- Drafting OpenAPI or GraphQL schemas from agreed requirements
- Generating endpoint code, client stubs and contract tests
- Writing and updating reference documentation and examples
- Analyzing logs for latency and error patterns

What our experts own:

- API design and versioning decisions
- Authentication, authorization and rate limits
- Reviewing every endpoint before release
- Breaking-change and deprecation policy

## How NPCoding delivers it

1. **Define the contract:** Agree on resources, payloads and errors in an OpenAPI or GraphQL schema first.
2. **Design security:** Choose authentication, permissions and rate limits based on who consumes the API.
3. **Build & test:** Implement endpoints with automated contract, integration and load tests.
4. **Document:** Publish reference docs, examples and changelogs alongside the code.
5. **Monitor & version:** Track usage, latency and errors, and evolve the API without breaking consumers.

## Connected capabilities

- [QA & Release Assurance](https://npcoding.ca/services/qa-testing/): Contract, integration and load tests run on every change, so consumers aren't the first to find a regression.
- [DevOps & Managed Operations](https://npcoding.ca/services/devops-managed-operations/): Versioned deployments with monitoring of latency, errors and usage per consumer.
- [Product Design & UI/UX](https://npcoding.ca/services/product-design-ux/): Developer documentation and portals are designed for the people who integrate, not just generated.

## How we build with AI

Both packages deliver APIs with the same contract tests and reviews. Choose based on where AI processing may happen while we build.

- [Private / Local AI Engineering](https://npcoding.ca/services/private-ai-engineering/): AI-powered software delivery in a controlled processing environment.
- [Claude Code & Codex Engineering](https://npcoding.ca/services/claude-code-codex-engineering/): AI-accelerated delivery with Claude Code and OpenAI Codex, directed by experienced engineers.

## Why NPCoding

- **Seamless connections:** Your apps, partners and systems exchange data reliably, in real time.
- **Secure by design:** Access control and validation are part of the architecture, not an afterthought.
- **Developer-friendly:** Clear docs and predictable behaviour make integration fast for every team.

## Tools and technologies

REST, GraphQL, OpenAPI, Node.js, TypeScript, PHP, OAuth 2.0 / OIDC, Redis, PostgreSQL, API gateways

## Industries

- [Finance](https://npcoding.ca/industries/finance/)
- [eCommerce](https://npcoding.ca/industries/e-commerce/)
- [Healthcare](https://npcoding.ca/industries/healthcare/)
- [Education](https://npcoding.ca/industries/education/)

## Related work

- [Hebrew University: a researcher portal powered by the university's own systems](https://npcoding.ca/case-studies/hebrew-university/): A fully custom English portal that shows researchers every instrument available for rent across departments and areas of expertise — with data pulled live from the university's systems through an API.
- [Startell: a web app that automates influencer campaigns — from finding creators to verifying their audiences](https://npcoding.ca/case-studies/startell/): A web application for an ad-tech company that connects brands with opinion leaders, analyzes influencers' followers for authenticity, and runs influencer campaigns with full automation.
- [Akko Port: a trilingual port website with real-time conditions and online mooring reservations](https://npcoding.ca/case-studies/akko-port/): A website for the historic port of Akko (Acre) in three languages — showcasing its attractions, displaying live weather conditions through an API, and letting boaters register and reserve a mooring spot.
- [Be'or HaTorah: a community commentary platform powered by a verse API](https://npcoding.ca/portfolio/beor-hatorah/): A social network for Torah learning built for the HaBanim non-profit: verses pulled through an API, commentary written and sourced by visitors, automatic author ranking by reads and dynamic highlights of leading commentaries.

## Frequently asked questions

### REST or GraphQL — which should we use?

REST is simple, cache-friendly and ideal for public or partner APIs. GraphQL shines when many clients need different slices of complex data, such as mobile and web apps sharing one backend. Many products use both; we choose per use case.

### How do you secure APIs?

With strong authentication (OAuth 2.0 / OpenID Connect or scoped keys), least-privilege authorization on every endpoint, input validation, rate limiting, encryption in transit and logging. We design against the OWASP API Security Top 10 and test those controls before release.

### Can you integrate a third-party API with poor documentation?

Yes. We build a thin, well-tested adapter around the third-party API, document what we learn, and add monitoring so changes on the provider's side are detected quickly.

### Will our API come with documentation?

Always. Every API we build ships with an OpenAPI (or GraphQL) schema, reference documentation and examples, kept in the same repository as the code so it never goes stale.

Discuss your API: https://npcoding.ca/contact/?topic=build&service=engineering#enquiry

---

NPCoding · AI-powered software & app development · Toronto, Canada · support@npcoding.com · https://npcoding.ca/contact/