.env to JSON Converter (Bidirectional, Nested Keys & Docker Compose)

What is this tool

This is a two-way .env and JSON converter built for developers who move configuration between shell environments, Docker, CI secrets and application code. Most "env to JSON" tools online split each line on the first = and call it done, which silently corrupts anything more interesting than KEY=value: a database URL with a colon, a multi-line RSA private key, a value with a trailing comment, or a JSON blob stored as a string. This tool parses character by character, the way the Node dotenv package and Docker Compose's own env-file loader do, so quoted values, backslash escapes, multi-line double-quoted blocks, inline comments and an optional export prefix are all handled the way they behave in a real shell.

The other direction — JSON back to .env — is just as easy to get wrong. A nested JSON config object has no direct .env representation, arrays and booleans need explicit string conversion, and a value containing a newline or a quote needs correct escaping or the resulting file won't parse. This tool flattens nested objects using a KEY__SUB double-underscore path convention (matching how dotenv-expand, Spring Boot and .NET configuration providers already read nested env vars), serializes non-string values sensibly, and quotes only the values that actually need it.

Because a .env file is rarely the final destination, the tool also generates two artifacts straight from the same parsed data: a docker-compose environment: list block with correct YAML quoting, and a TypeScript declare global augmentation of NodeJS.ProcessEnv so every key gets type-checked at compile time instead of coming back as string | undefined everywhere it's read. Everything — parsing, converting, generating all four output formats — runs as plain JavaScript in your browser tab; nothing is uploaded, logged or sent anywhere, which matters when the file you're pasting has real API keys and database passwords in it.

How to use it

1. Pick a direction: use the .env → JSON tab to paste dotenv content, or JSON → .env to paste a JSON object (flat or nested).
2. Paste your content into the input box, or click Load sample to see a worked example with quotes, a multi-line value and nested keys.
3. Toggle nesting on or off — with it on, keys like DATABASE__HOST become {"DATABASE":{"HOST":...}}; with it off you get a flat object with the raw double-underscore keys.
4. Click Convert (it also runs automatically as you type, debounced) to parse the input and generate all four outputs.
5. Switch output tabs between JSON, .env, docker-compose and TypeScript to preview each format, then Copy output or Download the active one.
6. Swap direction to send the current output back in as input — useful for round-tripping a file to confirm nothing was lost in translation.

Two worked examples

export NODE_ENV=production
# database connection
DATABASE__HOST=db.internal.example.com
DATABASE__PORT=5432
DATABASE__PASSWORD="p@ss w0rd \"quoted\""
APP_NAME=Checkout Service # inline comment stripped
FEATURE_FLAGS='["beta","dark-mode"]'

{
  "NODE_ENV": "production",
  "DATABASE": {
    "HOST": "db.internal.example.com",
    "PORT": "5432",
    "PASSWORD": "p@ss w0rd \"quoted\""
  },
  "APP_NAME": "Checkout Service",
  "FEATURE_FLAGS": "[\"beta\",\"dark-mode\"]"
}

{
  "PORT": 3000,
  "DEBUG": false,
  "REDIS": { "HOST": "localhost", "PORT": 6379 }
}

PORT=3000
DEBUG=false
REDIS__HOST=localhost
REDIS__PORT=6379

services:
  app:
    environment:
      - PORT=3000
      - DEBUG=false
      - REDIS__HOST=localhost
      - REDIS__PORT=6379

declare global {
  namespace NodeJS {
    interface ProcessEnv {
      PORT: string;
      DEBUG: string;
      REDIS__HOST: string;
      REDIS__PORT: string;
    }
  }
}

export {};

Frequently asked questions