karatelabs/karate

HTML feature report is very slow to open and uses excessive memory for large feature (177 scenarios, ~42 MB)

Open

#2,938 opened on Jun 23, 2026

View on GitHub
 (2 comments) (0 reactions) (0 assignees)Java (1,893 forks)batch import
help wanted

Repository metrics

Stars
 (7,600 stars)
PR merge metrics
 (Avg merge 14h 17m) (25 merged PRs in 30d)

Description

Description

Karate HTML reports work well for the summary page and for feature reports with a small number of scenarios. However, opening the HTML report for a feature with many scenarios is extremely slow and consumes a large amount of browser memory.

Environment

Item Value
Karate version 2.0.10
Java version 21
OS Ubuntu 24.04.4 LTS
Browser Chrome Version 149.0.7827.155 (Official Build) (64-bit)
Report type HTML (default)

Affected feature

  • Number of scenarios: 177
  • Generated HTML report file size of the specific feature: ~42 MB
  • Time to open/render in browser: ~1 min 40 sec
  • Browser memory usage while loading: ~6 GB
  • The report is served over HTTP

Expected behavior

The feature HTML report should load in a reasonable time without consuming several GB of RAM.

Actual behavior

  • The feature report page takes ~100 seconds to become usable.
  • Chrome uses ~6 GB of memory during/after loading.
  • Smaller feature reports and the summary page work fine.

Additional context

  • Tried to open it locally via file://, similar behavior
  • Tested in Edge, same behavior

Contributor guide

Research direction
Investigate the HTML report generation code in Karate. Profile the browser rendering of large feature reports and identify bottlenecks. Consider lazy loading, pagination, or reducing data serialization overhead.
Tech stack
javajavascript
Domain
testingperformance
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaHTMLJavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50