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JetStream 2

by JetStream 2

Paid Web

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What JetStream 2 is

JetStream 2.2 is a free, open-source web benchmark suite for JavaScript and WebAssembly, focused on advanced web applications. It measures browser startup, code execution, and smooth workload performance through 64 subtests. The workloads include WebAssembly, Web Workers, Promises, async iteration, Unicode regular expressions, JavaScript parsing, simulations, and a JavaScript implementation of a GPU shading-language benchmark called WSL. Results are combined with a geometric mean, giving each benchmark equal weight. Most JavaScript tests balance startup, worst-case, and average-case performance equally, while WebAssembly tests balance startup time and total execution time. Version 2.2 runs the same benchmarks as 2.1 but fixes issues involving timer resolution, segmentation subtests, and task-queue race conditions. It also includes fixes for command-line scripts used with D8 and SpiderMonkey shells. The maker reports stable scores in Chrome, Safari, and Firefox. Scores from JetStream 2.2 should not be compared with results from other JetStream versions.

Who it suits

JetStream 2.2 suits developers and browser evaluators comparing JavaScript and WebAssembly performance. Its command-line support also suits automated benchmark workflows.

What it does well

  • Free and open source
  • Includes 64 benchmark subtests
  • Covers JavaScript and WebAssembly workloads
  • Supports command-line scripts
  • Reports stable results across major browsers

What to know first

  • Scores cannot be compared across JetStream versions
  • Focuses on benchmark measurement rather than general software use
  • Most JavaScript tests use equal performance weighting

Verdict

JetStream 2.2 provides a broad, structured benchmark for advanced web workloads, with equal benchmark weighting and defined scoring rules. Use its results within version 2.2, since scores are not comparable with other JetStream releases.

Facts from JetStream 2's own pages

Benchmark size
JetStream 2.2 has 64 subtests. · browserbench.org, 12 Oct 2026
Browser stability
The maker reports measuring JetStream 2.2 scores in Chrome, Safari, and Firefox and finding them as stable as JetStream 2.1. · webkit.org, 12 Oct 2026
Changes in 2.2
JetStream 2.2 runs the same benchmarks as 2.1 and includes fixes for minor issues, including timer resolution and segmentation subtests. · browserbench.org, 11 Oct 2026
CLI or automation
Yes · browserbench.org, 22 Sept 2026
Command line
The maker says JetStream 2.2 includes fixes for command-line scripts used with D8 and SpiderMonkey shells. · browserbench.org, 12 Oct 2026
Founded
2019 · browserbench.org, 4 Oct 2026
JavaScript scoring
Most JavaScript benchmarks score startup, worst-case, and average-case performance equally. · browserbench.org, 11 Oct 2026
Overall score
The suite combines benchmark scores using a geometric mean, with each benchmark weighted equally. · browserbench.org, 11 Oct 2026
Purpose
JetStream 2.2 is a JavaScript and WebAssembly benchmark suite focused on advanced web applications. · browserbench.org, 12 Oct 2026
Score limitation
Scores from JetStream 2.2 are not comparable to scores from other versions of JetStream. · browserbench.org, 12 Oct 2026
Scoring
It combines individual benchmark scores using a geometric mean, with each benchmark weighted equally. · browserbench.org, 12 Oct 2026
Subtests
JetStream 2.2 has 64 subtests, including a JavaScript implementation of a GPU shading language benchmark called WSL. · browserbench.org, 11 Oct 2026
Version changes
JetStream 2.2 runs the same benchmarks as 2.1 and fixes several issues, including timer resolution and task queue race conditions. · browserbench.org, 12 Oct 2026
Version limitation
Scores from JetStream 2.2 are not comparable with scores from other JetStream benchmark versions. · browserbench.org, 11 Oct 2026
WebAssembly scoring
WebAssembly benchmark scores weigh startup time and total execution time equally. · browserbench.org, 11 Oct 2026
What it measures
It rewards browsers that start up quickly, execute code quickly, and run smoothly. · browserbench.org, 12 Oct 2026
Workload areas
JavaScript,WebAssembly,Web Workers,Promises,async iteration,Unicode regular expressions,JavaScript parsing,simulations · browserbench.org, 22 Sept 2026
Workloads
Its benchmarks cover WebAssembly, Web Workers, Promises, async iteration, Unicode regular expressions, and JavaScript parsing. · browserbench.org, 12 Oct 2026

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