[epos]

Web Extension Engine.

As of June 2026, [epos] has 3 users and a 5.00/5 rating from 1 reviews in the Developer Tools category.

Developer Tools

Chrome Web Store ↗.crx

Users0%

Rating0%

5.00

1 reviews

Reviews0%

Version

1.11

Manifest V3

90-day change · In the last 90 days this extension 2 version updates, changed permissions.

History

9 snapshots

Tracking since Apr 1, 2026.

View as table

Date	Users	Rating	Reviews	Version
Apr 1, 2026	3	5.00	1	1.7
Apr 18, 2026	2	5.00	1	1.7
Apr 24, 2026	5	5.00	1	1.10
May 1, 2026	3	5.00	1	1.10
May 12, 2026	3	5.00	1	1.11
May 18, 2026	5	5.00	1	1.11
May 24, 2026	3	5.00	1	1.11
May 31, 2026	5	5.00	1	1.11
Jun 6, 2026	4	5.00	1	1.11
Now	3	5.00	1	1.11

Changelog

Apr 18, 2026

description

Epos helps you build browser extensions and experiment with browser APIs interactively. It complements the documentation — instead of just reading about an API, you can execute it and observe the results in real time.

To try it out, install Epos extension and navigate to https://epos.dev/@learn. You can click the available buttons to see how different browser APIs behave, or open DevTools and use epos.browser to explore the APIs directly.

Epos is an extension for building Chromium extensions with React. Connect your local folder to Epos and start developing. When ready, just click "Export" to get a standalone ZIP file that you can publish.

⚡ What Epos gives you:

• A cross-context messaging system.
• Shared state with persistence and sync.
• Storage for files and other data.
• Extension APIs available in any context.
• Automatic script injection + Shadow DOM.
• A simpler setup through epos.json.

⚠️ Core Constraints:

• React: Epos is built around React.
• Chromium: Firefox and Safari are not supported.
• Manifest V3: No support for the legacy Manifest V2.
• No HMR: Live reload is available, but hot module replacement is not.
• No Source Maps: Epos injects its runtime into your code, so source maps do not work.
• Permissions: Certain manifest permissions are required and cannot be omitted.

To try it out, install Epos and follow the guide at https://epos.dev/guide/basics

Apr 18, 2026

short_description

Build browser extensions.

Web Extension Engine.

Apr 18, 2026

permissions

alarms, background, browsingData, contextMenus, cookies, declarativeNetRequest, downloads, notifications, offscreen, scripting, sidePanel, storage, tabs, unlimitedStorage, webNavigation

alarms, offscreen, unlimitedStorage, declarativeNetRequest, scripting, tabs, webNavigation, background, browsingData, contextMenus, cookies, downloads.ui, downloads, notifications, sidePanel, storage

Permissions & access

Permissions: alarmsoffscreenunlimitedStoragedeclarativeNetRequestscriptingtabswebNavigationbackgroundbrowsingDatacontextMenuscookiesdownloads.uidownloadsnotificationssidePanelstorage
Host access: <all_urls>

Screenshots

About

Epos is an extension for building Chromium extensions with React. Connect your local folder to Epos and start developing. When ready, just click "Export" to get a standalone ZIP file that you can publish.

⚡ What Epos gives you:

• A cross-context messaging system.
• Shared state with persistence and sync.
• Storage for files and other data.
• Extension APIs available in any context.
• Automatic script injection + Shadow DOM.
• A simpler setup through epos.json.

⚠️ Core Constraints:

• React: Epos is built around React.
• Chromium: Firefox and Safari are not supported.
• Manifest V3: No support for the legacy Manifest V2.
• No HMR: Live reload is available, but hot module replacement is not.
• No Source Maps: Epos injects its runtime into your code, so source maps do not work.
• Permissions: Certain manifest permissions are required and cannot be omitted.

To try it out, install Epos and follow the guide at https://epos.dev/guide/basics