$ npm install yslow -g

$ yslow --help Usage: yslow [options] [file ...] Options: -h, --help output usage information -V, --version output the version number -i, --info <info> specify the information to display/log (basic|grade|stats|comps|all) [basic] -f, --format <format> specify the output results format (json|xml|plain) [json] -r, --ruleset <ruleset> specify the YSlow performance ruleset to be used (ydefault|yslow1|yblog) [ydefault] -b, --beacon <url> specify an URL to log the results -d, --dict include dictionary of results fields -v, --verbose output beacon response information Examples: yslow file.har yslow -i grade -f xml -b http://server.com/beacon file1.har file2.har yslow -info all --format plain /tmp/*.har yslow -i basic --rulseset yslow1 -d < file.har curl example.com/file.har | yslow -i grade -b http://server.com/beacon -v More Info: http://developer.yahoo.com/yslow/help/beacons.html#version2

$ node > require('fs').readFile('example.com.har', function (err, data) { var har = JSON.parse(data), YSLOW = require('yslow').YSLOW, doc = require('jsdom').jsdom(), res = YSLOW.harImporter.run(doc, har, 'ydefault'), content = YSLOW.util.getResults(res.context, 'basic'); console.log(content); }); { w: 98725, o: 89, u: 'http%3A%2F%2Fexample.com%2F', r: 9, i: 'ydefault', lt: 981 }