A modern online IDE and API for executing COBOL code in the browser. Built with Next.js and designed for serverless deployment.

Click the button above to deploy your own instance on Vercel in seconds!

• Online IDE: Monaco Editor with COBOL syntax highlighting
• Real-time Execution: Run COBOL code instantly in the browser
• API Endpoint: RESTful API for programmatic access
• Serverless Ready: Optimized for Vercel, AWS Lambda, and other platforms
• No Dependencies: Pure JavaScript COBOL interpreter
• Modern UI: Clean, responsive interface

Endpoint: POST /api/interpret

Request Body: ```json { "code": "IDENTIFICATION DIVISION.\nPROGRAM-ID. HELLO.\n\nPROCEDURE DIVISION.\nDISPLAY "Hello, World!".\nSTOP RUN." } ```

Response: ```json { "success": true, "output": ["Hello, World!"], "errors": [], "warnings": [], "executionTime": 15, "variables": {} } ```

```bash curl -X POST https://your-deployment.vercel.app/api/interpret
-H "Content-Type: application/json"
-d '{ "code": "IDENTIFICATION DIVISION.\nPROGRAM-ID. HELLO.\n\nPROCEDURE DIVISION.\nDISPLAY "Hello, World!".\nSTOP RUN." }' ```

```javascript const response = await fetch('/api/interpret', { method: 'POST', headers: { 'Content-Type': 'application/json', }, body: JSON.stringify({ code: ` IDENTIFICATION DIVISION. PROGRAM-ID. CALCULATOR.

  DATA DIVISION.
  WORKING-STORAGE SECTION.
  01 WS-NUM1 PIC 9(3) VALUE 100.
  01 WS-NUM2 PIC 9(3) VALUE 50.
  01 WS-RESULT PIC 9(4).
  
  PROCEDURE DIVISION.
  ADD WS-NUM1 TO WS-NUM2 GIVING WS-RESULT.
  DISPLAY "Result: " WS-RESULT.
  STOP RUN.
`

}) });

const result = await response.json(); console.log(result.output); // ["Result: 150"] ```

• Node.js 18+
• npm or yarn

```bash

git clone https://github.com/webcobol/interpreter-web.git cd interpreter-web

npm install

npm run dev ```

Open http://localhost:3000 to see the IDE.

```bash npm run build npm start ```

• ✅ IDENTIFICATION DIVISION
• ✅ DATA DIVISION
• ✅ WORKING-STORAGE SECTION
• ✅ PROCEDURE DIVISION
• ✅ PIC clauses (X, 9, V)
• ✅ VALUE initialization
• ✅ DISPLAY statements
• ✅ MOVE operations
• ✅ Arithmetic (ADD, SUBTRACT)
• ✅ PERFORM loops
• ✅ IF-ELSE conditions
• ✅ Paragraph procedures

IDENTIFICATION DIVISION.
PROGRAM-ID. HELLO.

PROCEDURE DIVISION.
DISPLAY "Hello, COBOL World!".
STOP RUN.