Last week I watched a senior engineer paste a 4MB JSON payload into VS Code and wait 12 seconds for the linter to finish. Then they Cmd+F'd for the missing bracket. Then they gave up, re-ran the API call, and tried again. That whole detour was unnecessary. There are three places JSON validation lives in 2026 — the browser, the editor, and the shell — and each one wins in a different scenario. Mixing them up costs a few minutes a day. Once you stop mixing them up, you stop noticing the friction at all. This is a field guide to which tool actually wins for which task. Why "just use VS Code" is wrong VS Code's built-in JSON validator is excellent. It is also the worst answer to several common questions, because: It loads the whole file into memory. A 50MB log dump from CloudWatch hangs the renderer for seconds before you can scroll. It validates syntax, not shape.…