What Programming Language Is Open‑SEO Written In?

Open‑SEO is authored entirely in TypeScript, the statically‑typed superset of JavaScript, compiling to run on both Cloudflare Workers and Node.js environments.

The every‑app/open‑seo repository is a modern SEO platform built with type safety as a core architectural principle. According to the source code, the project leverages TypeScript across its entire stack—from server functions to database schemas—to ensure robust tooling and compile‑time error checking.

Evidence from the Source Code

Examining the repository root reveals immediate indicators of TypeScript authorship. The presence of tsconfig.json at the project root configures the TypeScript compiler with strict type‑checking rules. Additionally, package.json explicitly declares "typescript": "^5.9.3" as a development dependency, confirming the version used to build the application.

The codebase structure contains dozens of .ts files rather than plain JavaScript. For example, src/serverFunctions/keywords.ts implements server‑side logic using TypeScript interfaces and type annotations. This pattern repeats across the codebase, with files like src/shared/gsc.ts (Google Search Console integration) and src/db/schema.ts (database definitions) all bearing the .ts extension and containing strongly‑typed code.

Key TypeScript Implementation Patterns

The Open‑SEO codebase employs modern TypeScript patterns including async/await syntax and runtime type validation. Below is a representative example mirroring the style found in src/serverFunctions/keywords.ts:

// src/serverFunctions/example.ts
import { z } from "zod";

/** Input schema for the example endpoint */
const InputSchema = z.object({
  domain: z.string().url(),
});

/** Example server function */
export async function getExampleData(input: z.infer<typeof InputSchema>) {
  // Simulated asynchronous operation
  const response = await fetch(`https://api.example.com/seo?url=${input.domain}`);
  const data = await response.json();
  return data;
}

This snippet demonstrates two critical patterns used throughout Open‑SEO:

• Zod integration for runtime type safety, where z.infer<typeof InputSchema> extracts static TypeScript types from validation schemas.
• ES Module exports with explicit return type inference, allowing the compiler to verify data shapes before deployment.

Critical TypeScript Files in the Repository

Understanding the codebase structure requires examining specific files that define the TypeScript architecture:

• tsconfig.json — Configures compiler options including target environment and module resolution for the entire project.
• package.json — Declares TypeScript ^5.9.3 alongside related tooling dependencies.
• src/serverFunctions/keywords.ts — Contains server‑side business logic written entirely in TypeScript with typed function signatures.
• src/shared/gsc.ts — Implements Google Search Console API interactions using strongly‑typed interfaces.
• src/db/schema.ts — Defines database schemas using Drizzle ORM with TypeScript type definitions.

Runtime Compilation Target

While the source is written in TypeScript, the application compiles to JavaScript for execution. The repository configuration targets Cloudflare Workers and Node.js environments. The tsconfig.json settings ensure compatibility with these runtimes while preserving type safety during development.

Summary

• Open‑SEO is written entirely in TypeScript, not plain JavaScript.
• The repository uses TypeScript 5.9.3 as declared in package.json.
• Source files use the .ts extension, including critical paths like src/serverFunctions/keywords.ts and src/db/schema.ts.
• The codebase employs Zod for runtime validation combined with static type inference.
• TypeScript compiles to JavaScript for deployment on Cloudflare Workers and Node.js.

Frequently Asked Questions

Is Open‑SEO built with JavaScript or TypeScript?

Open‑SEO is built with TypeScript. While it runs as compiled JavaScript in production, every source file in the repository uses the .ts extension and includes type annotations. The tsconfig.json file enforces strict type checking, making TypeScript the primary development language.

What version of TypeScript does Open‑SEO use?

The repository specifies TypeScript ^5.9.3 in its package.json dependency list. This version provides the latest language features and compiler optimizations used throughout the server functions and database schema definitions.

How does Open‑SEO handle database operations in TypeScript?

Database operations use Drizzle ORM with TypeScript type definitions. The file src/db/schema.ts contains strongly‑typed schema definitions that provide autocomplete and compile‑time verification for all database queries, ensuring type safety from the application layer to the data layer.

Where does Open‑SEO deploy its compiled TypeScript code?

The TypeScript codebase compiles to JavaScript for deployment on Cloudflare Workers and Node.js environments. The tsconfig.json configuration targets these specific runtimes, enabling edge computing deployment while maintaining a single TypeScript source of truth.

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