---
title: "API-First Development — Definition & Engineering Context"
description: "API-First Development is an engineering approach that prioritizes the design and implementation of application programming interfaces (APIs) before building frontend client applications, ensuring system modules can easily integrate with external systems."
canonical: https://erpstack.io/glossary/api-first
markdown_url: https://erpstack.io/glossary/api-first.md
publisher: ERPStack
---

# API-First Development

> **Definition:** API-First Development is an engineering approach that prioritizes the design and implementation of application programming interfaces (APIs) before building frontend client applications, ensuring system modules can easily integrate with external systems.

## In depth

API-first development treats the API as a primary product. By defining strict API contracts (using tools like OpenAPI, GraphQL schemas, or TypeScript definitions) before writing frontend code, developers create highly reusable backend services. This architecture allows multiple clients—such as web apps, mobile apps, or third-party integrations—to query the same backend without custom translation layers.

## How ERPStack applies this

We build all ERP systems with an API-first approach, using tRPC and Zod schemas. This ensures that your backend forms a single source of truth that any mobile app or procurement channel can securely query.

## Related reading

- [Headless ERP](https://erpstack.io/glossary/headless-erp)
- [tRPC Protocol](https://erpstack.io/glossary/trpc)