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Compose environment value explorer

Trace Docker Compose interpolation and service environment values through supplied files, shell fixtures and overrides locally.

Choose a folder or ZIP. Files stay on this device. Configuration text is read locally; other files supply path/size inventory. No filesystem writes or commands run. Folder paths start below the selected folder.

Project/context folderProject ZIP (5 MB; 100 entries)

0 supplied files · folder inventory limit 2,000 · ZIP expanded limit 10 MB · 256 KB text per config / 6 MB package-lock.json. Empty directories and symlink targets are not represented.

Compose paths in CLI order (one per line)Explicit --env-file paths (one per line; blank uses project .env)Working directory in bundleProject directory override (blank: first Compose file directory)

Supplied shell fixture — JSON name/string-or-null map; no real shell is read

Optional image ENV and docker compose run -e fixtures

Image environment by service — JSON {service: {NAME: value}}Service selected by run -eRun environment — JSON; null means pass-through

Values never leave this device. Sources, unset/empty states and overrides are traced in two stages. Includes, extends, automatic COMPOSE_FILE secondary discovery and full Compose execution remain outside this supplied model.

What it does

Trace Docker Compose interpolation and service environment values through supplied files, shell fixtures and overrides locally.

How to use it

Import the relevant Compose and environment files, supply the shell values and command context you want to model, then inspect the trace.
Interpolation inputs and declared service environment values are separate stages. Follow the winning source and overridden values; image ENV is unknown unless supplied as a fixture.
Values stay in this browser. No shell, image environment, Docker daemon or remote file is read automatically; review reports before sharing them.

Example

A shell fixture overrides .env for interpolation, while an explicit service environment entry overrides that service's env_file value.

Methodology

Each supplied Compose file is interpolated before ordered service environment overrides. Supplied shell values take precedence in interpolation; service env_file lists append and explicit environment keys override their assignments. Source-linked traces distinguish this declared model from optional image ENV and run -e fixtures. Values and source text are hidden initially; export is redacted by default.

Limitations

2,000 folder files; 5 MB ZIP / 100 entries / 10 MB expanded; 256 KB per config or fixture / 10 MB combined file text, in decimal bytes. Up to 10 Compose and 10 interpolation env files, 100 services, 20 env_file entries per service, 1,000 variables per env file/fixture/service and 5,000 final rows. At most 2,000 expressions, 16 interpolation levels, 256,000 characters per expanded scalar, 2 million model/report characters and 30 seconds. Default .env uses the selected project directory. Automatic COMPOSE_FILE secondary discovery, includes, extends, profiles activation and full Compose null/reset merging remain unassessed. Image ENV stays unknown unless supplied. No shell, Docker execution or remote fetch.

Automation

This tool runs in your browser. No upload API or MCP endpoint is available.

View capabilities and documentation

Reference updated 2026-10-28

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