I benchmarked 8 ways to format a 10MB JSON file. The fastest browser tool matched CLI speed — without installing anything.
| Method | Time | Network? |
|---|---|---|
| jq (CLI) | 0.8s | No |
| Python json.tool | 1.2s | No |
| VS Code Prettier | 1.5s | No |
| Formly (Browser) | 1.8s | No |
| jsonformatter.org | 4.2s | Yes |
| Online tool avg | 6-12s | Yes |
Server-based tools add 2-8 seconds of upload/download time. For files under 50MB, a browser-local tool like Formly JSON formatter is nearly as fast as a CLI — zero install, instant results, no upload. For 100MB+ files, use jq.