Fast JSON Viewer — Benchmark

A standalone Playwright + Node script that measures, for any JSON file, how fast fastjsonviewer.com shows the first page and finishes parsing + validating it. Every run is cold — a fresh browser, nothing cached.

Or grab it from the command line and run it yourself:

Run it

# 1. Download the script into an empty folder
curl -O https://fastjsonviewer.com/benchmark.mjs

# 2. Install Playwright + a browser engine
npm init -y
npm install playwright
npx playwright install chromium

# 3. Run it against prod with your own files (matched by size)
node benchmark.mjs 1k.json 1MB.json 1gb.json

Files are matched by size, not name — call them whatever you like. The script prints a table and writes benchmark-results.json with the median, variance and full sample list for both metrics, plus the browser version.

Useful options

# Point it at a local or staging deployment
node benchmark.mjs --url http://localhost:4173/ 1k.json 1gb.json

# Change iterations, discard warmup runs, pick a browser
node benchmark.mjs --runs 21 --warmup 1 --browser firefox big.json

Full option list lives in the header comment at the top of the script.