Smart merge multiple .env files with conflict detection, deduplication, and sorting
Zero Dependencies · Works OfflineThe DotEnv Merger is a free online developer tool that intelligently merges multiple .env environment variable files. It automatically detects variable conflicts, supports multiple conflict resolution strategies, deduplication, and prefix-based group sorting, with export to .env, JSON, and other formats. Ideal for multi-environment config management, team collaboration on environment variables, and CI/CD env merging. All processing happens locally in your browser — environment variable content is never uploaded to any server.
1. Paste your .env and .env.override content into the respective input areas. .env.local is optional.
2. Select a conflict strategy: Latter overrides for environment overrides, mark conflicts for reviewing differences.
3. Select a sort mode: Group by prefix to categorize DB_, APP_, and other variables together.
4. Click "Merge" or press Ctrl+Enter to see the merged result and conflict information.
5. Copy or download the merged .env file.
Developers merge base .env with .env.production to quickly generate production configs without manual line-by-line comparison.
Team members merge their .env.local changes into the shared .env to ensure environment variable consistency.
DevOps engineers merge multiple services' environment variables into a unified env_file, simplifying Docker Compose configuration.
DotEnv is a popular environment variable management approach originating from Ruby's dotenv gem, later widely adopted by Node.js, Python, and other ecosystems. The .env file format is KEY=VALUE, one variable per line, with # for comments. Common conventions include: .env as base config, .env.local for local overrides (not committed to Git), .env.production for production, and .env.test for testing. Loading priority is typically local > environment > base. When merging, note: quoted values should preserve quotes, empty values (KEY= vs KEY) have different semantics, and multiline values use double-quote wrapping.
Standard .env format (KEY=VALUE) with comments (# prefix) and blank lines. Also supports quoted and multiline values.
The tool marks all conflicting variables and highlights them. Users can choose to keep the former, keep the latter, or manually select.
2-3 sources simultaneously. For more files, merge partial results first, then merge again.
Yes. All processing happens locally in your browser. Environment variable content is never uploaded.
Export as .env format, JSON format, and Docker Compose env_file format.
Yes. Drag .env files onto the input area to auto-load content.
Variables are automatically grouped by their underscore prefix (e.g., DB_, APP_, REDIS_), sorted alphabetically within groups, and groups sorted by group name.