Docker Compose Validator

Lint your docker-compose.yaml for common issues.

freeworks offlinenothing uploaded
Input
Output
—

About docker compose validator

Docker Compose Validator works entirely in the browser tab. Open it, use it, close it. Nothing about the session outlives the page.

Paste a customer record into it if you need to. The record never leaves the machine you are sitting at.

You will find it under Containers & deploys, alongside 7 other tools for the same sort of job.

Detects :latest tags, privileged mode, outdated versions, port binding risks, and mixed indentation.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

Catch security and best-practice issues
Detect :latest image tag, privileged mode, and port binding to all interfaces in a Compose file
Input
services:
  web:
    image: nginx:latest
    ports:
      - "80:80"
    privileged: true
Output
# docker-compose Validation

Services found: web
Errors: 0 | Warnings: 2 | Info: 1

## Warnings
  - Line 3: Avoid using ':latest' tag for image in service 'web'
  - Line 6: privileged mode is enabled for 'web'. This is a security risk.

## Info
  - Line 5: Port 80:80 binds to all interfaces. Consider binding to 127.0.0.1 for local-only access.

Questions

Does Docker Compose Validator work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use Docker Compose Validator on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.