Chrome Extension Starters

Executive Summary

The Chrome Extension Starter sector has converged sharply. Eighteen of 24 in-cluster repos are confirmed or likely targeting Manifest V3, and among recently pushed starters MV3 is effectively universal. The current fresh-project default is Vite + TypeScript + React + HMR + MV3.

That convergence has a cost: 54% of repositories are Strong Defaults. They are real, maintained starters, but they are difficult to distinguish once a builder has chosen React + TypeScript + Vite + MV3. The Differentiation Index is 1.79/5, the lowest sector-level differentiation Diversum has measured so far.

Six Category Leaders define the practical default for builders. Two repos sit in Adjacent Infrastructure positions for different reasons: EmailThis is a high-adoption MV2 historical predecessor, while fregante/browser-extension-template is a deliberate no-build, no-popup counter-centroid.

The sector shows no Inactive Scaffolds. Every in-cluster repo exhibits real human engineering, which separates Chrome Extension Starters from younger ecosystems where abandoned or auto-generated scaffolds are easier to surface.

About This Report

Who We Are

Diversum is a sector analysis project that maps convergence patterns in software ecosystems. We identify what the default project looks like in a given sector, measure how individual projects relate to that default, and surface where genuine differentiation exists.

This report applies the same public Sector Radar template used for the MCP Memory Servers report, with the Chrome Extension Starter corpus substituted into the same methodology, role vocabulary, and correction path.

Conflict of Interest Disclosure

Diversum has no affiliation with any repository in this corpus. No project in this report is built or maintained by the report authors.

Evidence Snapshot

All scores in this report are frozen at the evidence snapshot date of 2026-05-12. Adoption metrics, star counts, repository activity, manifest status, and package contents were not re-verified after this date. Repositories may have changed since.

Correction Invitation

If you are a maintainer of a project assessed in this report and believe your assessment contains an error, we invite you to request a review. Contact us at hello@diversum.dev. We will review the evidence and publish any corrections transparently.

Methodology

Key Terms

• Synthetic centroid — The composite default project assembled from traits shared by most projects in a sector. Not a real project; a statistical description of the sector's convergence pattern.
• In-cluster — Repositories whose primary purpose is to serve as fork-and-build Chrome or Chromium extension starters. These define the centroid.
• Two-pass denominator — A method for building the centroid from the right subset. Pass 1 surveys the candidate corpus; Pass 2 excludes adjacent frameworks, samples, plugins, lists, stale repos, and archived repos before calculating the default pattern.

The Synthetic Centroid

Instead of comparing every starter to a single reference product, we construct a synthetic centroid: the composite default starter produced by the sector's recurring traits. A trait qualifies for the centroid if it appears in more than 50% of the in-cluster sample. The centroid is defined by what is common, not what is good.

Two-Pass Denominator Protocol

Searches for Chrome extension starters return frameworks, plugins, samples, CLI generators, and finished extensions alongside true fork-and-build starters. Including those adjacent artifacts in the centroid would distort the default Chrome Extension Starter pattern.

We address this with a two-pass method:

• Pass 1: Survey candidate repositories and document boundary pressure, stale repos, archived repos, and adjacent tooling.
• Pass 2: Define the centroid from the 24 retained starter repositories only. Adjacent tools remain visible where they affect builder discovery, but they do not define the starter default.

The final denominator is 24 repositories: 23 strict-intake candidates, minus one stale repo, plus two topic-tag additions surfaced during cross-checking.

Five Radar Dimensions

Each repository is scored on five dimensions, each on a 0-5 scale:

Cluster Roles

Roles are assigned algorithmically from dimension scores. Public-facing labels follow the softer SC-010 vocabulary:

The Sector

What Chrome Extension Starters Are

A Chrome Extension Starter is a public GitHub repository intended as a fork-and-build scaffold for new browser extensions targeting Chrome or Chromium. A starter must include a manifest file, build tooling, and at least one wired extension surface such as a popup, content script, background service worker, options page, devtools panel, or side panel.

This boundary excludes frameworks installed as dependencies, build-tool plugins, CLI scaffolders, official Google samples, curated lists, finished extensions, and generic web app starters.

Why This Sector Exists

Browser extensions are small products with unusually specific project structure: manifests, permissions, extension surfaces, content scripts, browser APIs, and packaging requirements. A general web app starter does not teach those constraints.

The sector has also been reshaped by Manifest V3 enforcement, Vite's rise as the default frontend build tool, and CRXJS's ability to bring HMR into extension development without replacing the underlying Vite mental model. The result is a visible generational split between older webpack or MV2 starters and newer Vite/MV3 starters.

The Synthetic Centroid

The default Chrome Extension Starter is a TypeScript-first, Vite-built, React-based scaffold targeting Manifest V3. It ships a popup, content script, and background service worker, claims or enables hot module replacement during development, targets Chrome first, and is maintained by a solo developer.

Centroid Traits (10)

Transition Traits

React, Chrome-first targeting, Vite, and HMR clear the greater-than-50% threshold by narrow margins. That narrowness is the sector story: older webpack and MV2 repositories still carry adoption, while recently active starters point strongly toward the modern Vite/MV3 stack.

Cluster Map

Category Leaders (6)

Projects with high engineering quality, strong adoption, and close sector alignment.

vitesse-webext is the highest-scoring repository in the corpus and the clearest example of engineering depth. It combines Vue 3, UnoCSS, pnpm, Vite, CRXJS, i18n, and cross-browser support.

JohnBra/vite-web-extension achieves the strongest centroid alignment: React, TypeScript, Vite, CRXJS, Tailwind, popup, content script, options, background service worker, and devtools panel.

abhijithvijayan/web-extension-starter and chibat/chrome-extension-typescript-starter show that the webpack era remains mature and actively used, even as the fresh-project default shifts to Vite.

Strong Defaults (13)

Strong Defaults are maintained, correctly scoped, and centroid-aligned. They are useful starters, but their value is usually stack preference rather than a distinct sector position.

Debdut is the closest to a differentiator in this group because it offers React, Vue, Svelte, and vanilla templates. NekitCorp and trentbrew keep Svelte visible. Most others are technically sound React + TypeScript + Vite or webpack implementations that compete on preference more than position.

Baseline Implementations (3)

Working starters with thinner engineering depth. These are appropriate for learning, quickstarts, or personal projects, but less compelling as durable production baselines.

Adjacent Infrastructure (2)

Both repos are genuine starters retained in the corpus. Their role reflects distance from the current 2026 centroid, not maintainer quality or category exclusion.

Sector Health

Primary Metrics (In-Cluster, n=24)

Key Findings

1. The Sector Has Converged on a Modern Default Pattern

MV3 + TypeScript + Vite + React + HMR now defines the default Chrome Extension Starter in 2026. Builders who want the standard approach have a clear target, especially in the recently active starter cohort.

2. The Webpack Era Is Legacy, Not Dead

chibat and abhijithvijayan are among the most-starred repositories in the corpus and remain relevant for builders who need a mature webpack setup or who are extending an older extension codebase.

3. Differentiation Happens at the Margins

Meaningful differences show up in framework choice, build philosophy, surface completeness, cross-browser commitment, and whether a starter takes a deliberate counter-centroid position.

4. EmailThis Is a Historical Artifact, Not a Current Recommendation

EmailThis has very high historical adoption, but it is MV2-based and should not be the starting point for current Chrome development. Its value is historical reference, not present-day default guidance.

5. The Vite + CRXJS Pairing Has Become a New Default

CRXJS adds native Chrome Extension HMR to Vite's standard build pipeline without turning a starter into a separate framework. Repos using CRXJS remain standard Vite projects.

6. Vue and Svelte Are Real Alternatives

vitesse-webext and mubaidr show that Vue is a first-class option in this sector, while NekitCorp and trentbrew keep Svelte visible. These alternatives are not merely decorative; they represent distinct builder contexts.

Differentiation Gaps

Open positions visible in the corpus: opportunities for new entrants or existing starters looking to become meaningfully distinct.

Sector Narrative

Chrome Extension Starters have passed through a rapid generational shift. The 2017-2021 era produced webpack-based, often MV2 or MV2-adjacent React starters that accumulated stars and forks over years. That cohort remains visible through EmailThis, chibat, abhijithvijayan, and satendra02.

The 2022-2024 era brought MV3 enforcement, Vite's ecosystem dominance, and CRXJS's HMR plugin. The new cohort is technically aligned with the fresh-project default but crowded: many starters offer React + TypeScript + Vite + MV3 with only small differences in surface coverage or style tooling.

The two repos that most clearly escape the central pattern occupy opposite edges. vitesse-webext shows what a highly opinionated, deeply maintained Vue starter can look like. fregante/browser-extension-template shows the counter-position: no build step, vanilla JavaScript, cross-browser-first, and no popup surface.

The middle of the sector is healthy and undifferentiated. The edges — side-panel-aware scaffolds, full-surface MV3 starters, no-framework TypeScript, and minimal-build current-era templates — remain open.

Appendix: Scoring Summary

All 24 Repositories

Cluster Composition

Methodology Notes

Dimension abbreviations: CM = Centroid Match, DF = Differentiation, HE = Human-Edge, AD = Adoption Depth, CI = Claim/Implementation Integrity.

Public role naming: Public labels describe observable sector position, such as Category Leader, Strong Default, Baseline Implementation, Inactive Scaffold, Adjacent Infrastructure, and Differentiated Niche. Public report pages do not expose internal Competitive Audit labels.

Limitations and objections: See the methodology limitations and anticipated objections sections for the boundary conditions of this analysis.

Source mapping: Chart-ready tables and source mappings are available in Visual Data. Full score derivations are available in Calibration.