# zeman/perfmap

Front-end performance heatmap bookmarklet.

Repository: https://github.com/zeman/perfmap
Canonical: https://ross.abutalabs.com/products/perfmap
Language: JavaScript
License Family: other
Last push: 2017-05-12T00:10:57+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4368, "days_push": 3401, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3766, forks 126 (observed 2026-08-28T04:08:18.048364+00:00)

## What it is
PerfMap is a bookmarklet and Chrome extension that overlays a performance heatmap on a webpage, visualizing when images finished loading during page load using the Resource Timing API. It helps front-end developers understand perceived load performance at a glance.

## Use cases
- visualize when images load during page load
- audit front-end performance of a webpage
- identify slow-loading images hurting user experience
- overlay a load-time heatmap on any site
- analyze resource timing in the browser

## When to choose
- you want a quick, zero-install visual check of image load times on any page
- you prefer a bookmarklet or lightweight extension over a full profiling suite
- you need to communicate load-time user experience to non-technical stakeholders

## When to avoid
- you need full waterfall analysis of all resource types, not just images
- you require automated or CI-based performance testing
- your browser lacks Resource Timing API support
- you need actively maintained tooling with ongoing fixes

## Facets
- artifact type: plugin
- maturity: maintenance
- function: monitoring, data-visualization, developer-tools
- domain: web-development, frontend, performance, browser-extensions
- platform: browser, browser-extension
- tags: bookmarklet, performance-heatmap, resource-timing-api, page-load-analysis, web-performance, javascript

## Member repositories
- zeman/perfmap (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:18.048364+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:22:20.942246+00:00, confidence not recorded.
  - readme: https://github.com/zeman/perfmap (fetched 2026-08-28T04:08:18.048364+00:00, sha f9139a5f39ad)
- Data as of 2026-08-30T08:39:29.467469+00:00.