What Is the Primary Programming Language Used in the Open-SEO Project?

Open-SEO is built primarily with TypeScript, utilizing .ts and .tsx files with ES-module syntax across the entire codebase.

The every-app/open-seo repository is a modern web application stack that relies on TypeScript as its foundational development language. According to the source code analysis, TypeScript provides the static typing, modern JavaScript features, and React integration that power the application's architecture.

Configuration Files Confirm TypeScript Usage

The project's build configuration explicitly defines TypeScript as the primary language. In tsconfig.json, the compiler configuration includes **/*.ts and **/*.tsx files, which is the canonical indicator that the entire codebase compiles through the TypeScript compiler.

Additionally, package.json declares "type": "module", enabling ES-modules—a standard setup for modern TypeScript projects that allows the use of import/export syntax throughout the application. These configuration files work together to enforce TypeScript as the development standard.

Core Implementation Files

All source files that implement core functionality are written as .ts or .tsx modules. The entry point at src/start.ts initializes the application using TypeScript import syntax and integrates with TanStack React Start, which itself is written entirely in TypeScript.

The src/serverFunctions/ directory contains additional TypeScript modules that handle server-side logic, maintaining consistent type safety across the full stack.

Entry Point Example

The src/start.ts file demonstrates the project's TypeScript implementation:

// src/start.ts
import { createStart } from "@tanstack/react-start";
import { globalServerFunctionMiddleware } from "@/serverFunctions/middleware";

export const startInstance = createStart(() => ({
  functionMiddleware: globalServerFunctionMiddleware,
}));

This code illustrates ES-module imports, TypeScript type annotations, and integration with the React Start framework.

TypeScript Features in the Codebase

Open-SEO leverages several advanced TypeScript capabilities:

• Static Typing: The compiler configuration enforces type safety across all modules
• TSX Support: React components use .tsx extensions for JSX type checking
• Path Mapping: The @/serverFunctions/ import alias demonstrates TypeScript's module resolution features
• Modern Syntax: The project uses contemporary ES-modules alongside TypeScript's type system

Summary

• Open-SEO uses TypeScript as its sole primary programming language, with no vanilla JavaScript source files in core implementation directories.
• Configuration in tsconfig.json and package.json explicitly targets TypeScript compilation and ES-modules.
• Entry points like src/start.ts and server functions in src/serverFunctions/* are implemented as .ts and .tsx modules.
• The codebase integrates with TanStack React Start, a TypeScript-first framework for building React applications.

Frequently Asked Questions

Is Open-SEO written in JavaScript or TypeScript?

Open-SEO is written entirely in TypeScript. While TypeScript compiles to JavaScript, the source code uses .ts and .tsx file extensions with explicit type annotations. The tsconfig.json file configures the TypeScript compiler to handle all source files, making TypeScript the primary development language rather than plain JavaScript.

Does Open-SEO use React components?

Yes, the codebase utilizes React components written in TypeScript. The use of .tsx file extensions and imports from @tanstack/react-start indicate that JSX components are fully integrated with TypeScript's type system. This allows for type-checked React props and component interfaces throughout the application.

What module system does Open-SEO use?

Open-SEO uses ES-modules (ECMAScript modules). The package.json specifies "type": "module", which enables the use of import and export statements rather than CommonJS require() and module.exports. This is the standard module system for modern TypeScript applications and aligns with the project's use of contemporary JavaScript features.

Where is the TypeScript configuration defined?

The TypeScript configuration is located in the repository root at tsconfig.json. This file specifies which files the compiler should include—specifically **/*.ts and **/*.tsx patterns—and configures compiler options for the project. It serves as the authoritative source for TypeScript settings across the Open-SEO codebase.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}