YAML Validator

How to use the YAML Validator

1. Paste your YAML or open a .yaml or .yml file.
2. Errors are shown with the line and column, plus a snippet of the problem area.
3. When the YAML is valid, see it cleaned up, as JSON, or as a short summary.
4. Copy or download the result.

Examples

service: shop-api
replicas: 3
ports:
  - 8080
  - 8443
env:
  LOG_LEVEL: info
  FEATURE_FLAGS: "beta,search"

database:
  host: db.internal
   port: 5432
  user: app

kind: Config
name: first
---
kind: Config
name: second

About this tool

YAML runs a large share of modern infrastructure: Docker Compose files, Kubernetes manifests, CI pipelines, Ansible playbooks and countless app configs. Its reliance on indentation makes it pleasant to read and easy to break. One extra space, a tab character or a missing colon can stop a deployment with a cryptic message.

This validator parses every document in the file and reports the first problem with its line and column, a plain-English explanation and a snippet showing where it happened. It catches tabs used for indentation, which YAML forbids, and keys that appear twice in the same block, which some tools silently accept by keeping the last value.

When the file is valid you can see how the parser understood it, which is the best way to spot subtle surprises: values such as no, on or 08 can be read differently from what you meant, and seeing the data as JSON makes the types obvious. Comments are not kept in the cleaned output, so keep your original file.