Every DevOps engineer has done this dance: you've got a chunk of YAML or a Terraform file that looks right, something's rejecting it, and you want a fast sanity check. So you paste it into some random online validator — and a small voice asks, wait, where did that config just go?
That config often has structure, comments, sometimes internal hostnames or resource names in it. Pasting infrastructure definitions into an unknown server is a habit worth breaking. So I built a set of validators that never send your config anywhere — they run entirely in your browser.
What they are
Free, browser-based validators for the formats DevOps folks paste-and-pray most:
- YAML — catches the indentation and structure errors that make Kubernetes and CI configs fail with cryptic messages
-
Kubernetes manifests — schema-aware checks beyond "is it valid YAML," so you catch the wrong
apiVersionor a misplaced field beforekubectl applydoes -
Terraform / HCL — structural validation for the syntax slips that
terraform validateflags only after you've context-switched away
The one design decision that matters
100% client-side. No upload, no signup, no server round-trip. Your config is parsed by JavaScript running in your own tab — it never leaves your machine. You can literally open dev-tools, watch the network panel, and see nothing go out. Turn off your wifi and they still work.
This isn't a privacy gimmick — it's the correct architecture for a tool that handles infrastructure definitions. A validator has no business seeing your config on a server it doesn't need to.
Why I bother
Two reasons, honestly.
One: I kept wanting this exact thing and kept not trusting the options. The nth time I hesitated before pasting a manifest into a stranger's website, I decided to just build the version I'd trust.
Two: fast feedback loops are the whole game in this job. The gap between "save the file" and "find out it's malformed" is pure friction — and the tighter that loop, the less of your working memory it burns. A validator that's one tab away and gives an answer in milliseconds is a small thing that compounds.
Try them
- The validator workbench — YAML, Kubernetes, and Terraform, all client-side
If you're the kind of person who'd rather script it, a lot of the underlying tooling is open source — CLIs and a small read-only API for the prompt and error-guide data — over on the developer page and the GitHub org.
Client-side tools have real limits — they can't know your cluster's live state, and schema validation isn't the same as a policy check. But for the "did I just fat-finger the indentation" question, having the answer without a network request is exactly the trade I want.
What config format do you most wish had a trustworthy, offline, no-signup validator? That's genuinely how I decide what to build next.
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