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About Docker Compose Validator

Docker Compose Validator is a browser-based developer utility that validates both the YAML syntax and the structural specification of docker-compose files.

It checks service definitions, detects typographical errors in directive keys, verifies network and volume cross-references, validates port mapping formats, and provides visual architecture summaries for your multi-container stacks.

Key features

  • YAML Syntax & Indentation Check Detects YAML indentation errors, tab characters, and unquoted scalar issues with exact line and column numbers.
  • Compose Schema Integrity Validates top-level sections (services, networks, volumes, configs, secrets) and flags invalid root-level declarations.
  • Service & Port Format Validation Scans service attributes for common typos (e.g. images vs image, depend_on vs depends_on) and verifies port mapping syntax like 8080:80.
  • Cross-Reference & Dependency Verification Ensures named networks, named volumes, and depends_on targets declared under services correspond to defined resources.

How to validate a docker-compose file

Follow these steps to check and troubleshoot your Docker Compose configuration.

  1. Enter Compose YAML content Paste your docker-compose.yml content into the editor or pick one of the sample application templates.
  2. Inspect validation results Review the live status banner showing whether the configuration is valid, contains warnings, or has syntax errors.
  3. Navigate to issues by line Click on any listed error or warning in the report panel to jump directly to the offending line in the editor.
  4. Examine service architecture & export Check the parsed architecture cards to confirm port bindings, images, and network links, then format and copy the clean YAML.

Usage tips

  • Always quote port mappings like "8080:80" because YAML parsers can interpret unquoted colon values as base-60 numbers.
  • YAML strictly forbids tab characters for indentation; make sure your editor inserts 2 spaces.
  • In modern Docker Compose Specification, the top-level version directive is optional.
  • Verify that any named volume used in a service is declared under the root volumes: section.

Frequently asked questions

The validator supports modern Compose Specification files as well as legacy Compose file formats v2 and v3.
No. Validation runs entirely client-side in your browser, analyzing YAML syntax and Compose structural specifications without requiring a running Docker daemon or server connection.
Yes. The validator scans all service port declarations and warns you if two separate containers attempt to bind to the same host port.
The validator inspects each service networks and volumes mapping to verify that any non-default named references exist in the root networks and volumes sections.