Should we build a REST API or use GraphQL?

REST is the right choice for most APIs. GraphQL is valuable when consumers have significantly varied data requirements. For most business APIs, REST is simpler, more predictable, and easier to secure.

How do you handle API versioning?

URL-based versioning as standard - /api/v1/, /api/v2/. We design the initial API with versioning in mind so breaking changes can be introduced alongside existing versions with a clear deprecation timeline.

Can you build on top of our existing database?

Yes - building an API layer on top of an existing database is common. We assess the schema, understand the business domain, and design the API to expose data through a clean, consistent interface.

How do you ensure the API is secure?

Security is built in from the design phase: authentication on every endpoint, authorisation at the API layer, input validation, rate limiting, HTTPS enforcement, and OWASP API Security Top 10 as a minimum standard.

Bespoke REST API Development

Q: Can you provide an API for our third-party partners to integrate with?

Yes - we design partner-facing APIs with comprehensive documentation, stable versioning, sandbox environments, and authentication models appropriate for third-party use.

The backend layer that powers your web applications, mobile apps, third-party integrations, and internal tools - built to a production standard.

Book a Free Consultation

Bespoke API Development

We design and build bespoke REST APIs for businesses across the UK and Isle of Man. The backend layer that powers your web applications, mobile apps, third-party integrations, and internal tools - built to a production standard, documented thoroughly, and designed to scale with your business.

An API is the foundation that everything else is built on. A well-designed API makes building web applications, mobile apps, and integrations faster and more reliable. A poorly designed API - one with inconsistent conventions, inadequate error handling, no versioning strategy, and insufficient documentation - makes every downstream project harder and more expensive. The quality of your API determines the quality of everything that depends on it.

Every API we build is designed and delivered personally by Owen Jones, OLXR's founder and lead engineer. We take an API-first approach to software development - designing the API contract before building the consumers of it - because an API designed around its consumers produces a cleaner, more consistent interface than one that emerges organically as applications are built.

Who This Is For

Businesses building a web application and mobile app simultaneously that need a shared backend API powering both

Companies that want to expose their business data or functionality to third-party developers, partners, or customers through a public API

Organisations building a platform where multiple internal or external applications need to access shared business logic and data

Development teams that need a well-designed API built by an experienced backend engineer before frontend development begins

Businesses that need to replace an existing poorly designed API without disrupting the applications that depend on it

SaaS companies that want to offer API access as a product feature for their technical customers

What We Deliver

RESTful API Design

Consistent, intuitive API contracts designed around your business domain and your consumers' needs.

Authentication and Authorisation

API key management, OAuth2, JWT, and role-based access control implemented correctly.

Comprehensive Error Handling

Consistent, informative error responses that make client-side error handling straightforward.

API Versioning

A versioning strategy that allows the API to evolve without breaking existing consumers.

Rate Limiting and Throttling

Protection against abuse and fair usage enforcement built into the API layer.

OpenAPI and Swagger Documentation

Complete, accurate API documentation that developers can use to build integrations without assistance.

Webhook Support

Outbound event notifications that allow third-party systems to react to events in your platform.

Performance and Scalability

Caching strategies, query optimisation, and infrastructure design for APIs at scale.

Our Approach

Design the Contract Before the Implementation

API-first development means designing the API contract - the endpoints, the request and response structures, the error codes, the authentication model - before writing any implementation code. This produces APIs that are designed around the needs of their consumers rather than the convenience of their implementation, and that are consistent across all endpoints because the design was considered holistically rather than endpoint by endpoint. We produce an OpenAPI specification at the design stage that can be reviewed and agreed before development begins.

Design for Longevity

APIs are contracts with their consumers. Breaking changes - removing endpoints, changing response structures, altering authentication requirements - have consequences for every application and integration that depends on the API. We design APIs with longevity in mind: consistent conventions, a clear versioning strategy, and the foresight to accommodate anticipated future requirements without breaking existing consumers. An API designed for longevity costs less to maintain and allows the business to move faster over time.

Document as a First-Class Deliverable

An API without accurate documentation is an API that is difficult and expensive to use. We produce comprehensive OpenAPI documentation for every API we build - documenting every endpoint, every request parameter, every response field, and every error code accurately. We also provide example requests and responses, authentication guides, and getting started documentation for the most common integration scenarios. Documentation is a deliverable, not an afterthought.

Why Choose OLXR

API design is a discipline where experience compounds. Naming, response structure, error codes, versioning - small decisions that quietly accumulate technical debt with every new consumer if you get them wrong.

Designed To Last

Versioning, naming and error design built for the long term

Production-Ready

Auth, webhooks and rate limiting that hold up under real load

Documented Properly

OpenAPI specs and examples your consumers can actually use

Senior-Led

Every shortcut in API design becomes a breaking change later - we'd rather take the extra time up front than apologise to your consumers in twelve months.

OJ

Owen Jones

Founder & Lead Engineer

Technologies We Use

ASP.NET Core

REST

OpenAPI

JWT

OAuth2

SQL Server

PostgreSQL

EF Core

Hangfire

AWS

Azure

Docker

Don't see your stack? Get in touch.

Frequently Asked Questions

REST is the right choice for most APIs - it is well understood, well tooled, and appropriate for the vast majority of use cases. GraphQL is valuable when your API consumers have significantly varied data requirements that REST's fixed response structures handle inefficiently - for example, a public API serving many different client applications with very different data needs. For most business APIs serving a defined set of consumers, REST is simpler, more predictable, and easier to secure. We will give you an honest recommendation for your specific situation.

We implement URL-based versioning as standard - /api/v1/, /api/v2/ - because it is explicit, well understood, and easy to implement correctly. We design the initial API with versioning in mind so that when breaking changes are needed, a new version can be introduced alongside the existing one with a clear deprecation timeline for the old version. Consumers are never broken by API changes without warning and a migration path.

Yes - building an API layer on top of an existing database is a common project. We assess the existing database schema, understand the business domain it represents, and design the API to expose that data through a clean, consistent interface. Where the database structure creates challenges for a clean API design, we will tell you what those challenges are and recommend the most practical way to address them.

API security is built in from the design phase. Every endpoint requires authentication unless there is a specific reason for it to be public. Authorisation is enforced at the API layer so that authenticated users can only access data and perform actions they are permitted to. Input validation prevents injection attacks. Rate limiting prevents abuse. HTTPS is enforced. We follow OWASP API Security Top 10 as a minimum standard and document the security model as part of the API documentation.

Yes - building APIs for third-party consumption is something we do regularly. Partner-facing APIs have specific requirements beyond internal APIs: comprehensive documentation, stable versioning, sandbox environments for integration testing, and authentication models appropriate for third-party use. We design partner APIs with these requirements in mind from the start rather than adapting an internal API for external use.

Related Services

Web Applications

SaaS platforms and custom web apps

API Integrations and Automation

Connecting your business systems

Mobile Applications

iOS and Android development

Ready to Build Your API?

Tell us what you need the API to do and what will consume it. We will give you an honest view of the right design approach and what it would take to build it properly.

Let's Talk