YAML validator
Paste YAML to check syntax in the browser. Invalid documents highlight the problem line and suggest how to fix it.
About YAML validator
Validate YAML syntax online, see the exact line that breaks parsing, and get a suggested fix. This free YAML validator catches the problems that most often break a build: bad indentation, tabs instead of spaces, missing colons, duplicate keys, and unquoted special characters. Use it before committing Kubernetes manifests, Docker Compose files, GitHub Actions workflows, Ansible playbooks, or application config.
YAML looks simple until indentation silently changes a list into a string. A validator that points at the line saves a failed pipeline and a long stare at whitespace. Platform engineers, DevOps, and app developers paste a snippet, fix the reported line, and paste again until it parses. Suggested fixes help when the error message from a cluster or CI log is hard to map back to the file.
The validator parses in the browser. It does not apply a Kubernetes schema or Compose spec; it tells you whether the YAML is syntactically valid. After it parses, use the YAML formatter to normalize indent or convert to JSON. Invalid YAML never silently becomes empty JSON.
Validation runs entirely in your browser, so infrastructure files stay private. Cluster secrets and internal hostnames are not uploaded. Use this free online YAML validator and YAML linter whenever you need a private syntax check before you deploy.
Features
- Check YAML syntax, highlight the bad line, and suggest a fix
- Paste text or load a file and get a result in one click
- Copy or download the output for your project
- Input for YAML validator is processed in your browser
- No signup and no intentional server-side storage of tool input
How to use YAML validator
- Paste text or load a file into YAML validator.
- Choose the format, compare, validate, or convert action you need.
- Copy the result or download it for your project.
- Input is processed in your browser and is not uploaded for this tool.
Frequently asked questions
Is YAML validator free?
Yes. YAML validator on Free Tool Mate is free to use in your browser. There is no paid unlock for the core tool features described on this page.
Does YAML validator upload my data?
No. YAML validator is designed to process your input locally in the browser. Free Tool Mate does not intentionally store tool input or uploaded files on the server.
Do I need an account to use YAML validator?
No account is required. Open the page, use YAML validator, and leave when you are done.
What can I use YAML validator for?
YAML validator covers Check YAML syntax, highlight the bad line, and suggest a fix. It is built for quick, private work in the browser without installing desktop software.