Open-source email tracker blockers

Three current receiving-side Chrome blockers provide a public audit surface. Ugly Email 4.1.2 is a Gmail-focused blocker whose repository includes an MIT license. Trocker 3.4.1 uses Apache-2.0 and documents known-tracker blocking across webmails with enhanced handling in Gmail, Yahoo Mail and Outlook.com. Mailshade 1.1.0 is the current public Chrome Web Store version and declares six opt-in webmail integrations, reviewed endpoint DNR blocking, local sender-level history and supported tracking-link warnings. Mailshade also makes AGPL-3.0-or-later source archives and checksums available; reviewers must match an archive to the exact tested package version. Source availability lets a reviewer inspect permissions, storage and network paths; it does not by itself establish blocking recall or benign-message precision. Licenses also answer different reuse and distribution questions and should not be converted into an efficacy score. This page therefore records the source and version evidence while leaving the comparative result pending until all three pinned builds complete the same controlled corpus and the raw observations are public.

Comparison record

Facts reviewed on 2026-08-21.

Result: pending

Test date: Not yet tested; no performance winner is claimed.
Methodology: Read the published method

Versions in scope

Mailshade: 1.1.0 — Current public Chrome Web Store version confirmed on 2026-08-19.
Trocker: 3.4.1
Ugly Email: 4.1.2 — Version recorded from the official source repository.

Method and current result

Each pinned extension must run in a clean Chrome profile against the same versioned pixel, link and benign-content fixtures before comparative performance is stated.

License, version and publisher-stated scope are verified from public sources; no performance ranking is claimed until raw shared-corpus results exist.

Claim evidence

[verified] Mailshade 1.1.0 is the current public Chrome Web Store version, confirmed on 2026-08-19. source 1
[verified] Mailshade makes AGPL-3.0-or-later source archives and checksums available; an archive must be matched to the exact tested package version before it is package evidence. source 1
[verified] Trocker 3.4.1 publishes source under Apache-2.0 and documents multi-webmail blocker behavior. source 1, source 2
[verified] Ugly Email 4.1.2 has a public repository whose LICENSE file contains the MIT license. source 1, source 2
[pending] Relative protection efficacy and false-positive rates for the three pinned builds remain unmeasured.

Sources

Mailshade Chrome Web Store listing, Mailshade; accessed 2026-08-19.
Mailshade source archives and checksums, Mailshade; accessed 2026-08-21.
Trocker Chrome Web Store listing, Trocker; accessed 2026-08-16.
Trocker source repository and license, Trocker; accessed 2026-08-16.
Ugly Email package version, OneClick Lab; accessed 2026-08-16.
Ugly Email MIT license, OneClick Lab; accessed 2026-08-16.

Ugly Email 4.1.2

Ugly Email's official site and repository describe a Gmail extension that identifies and blocks tracking pixels, marks tracked messages and stores its data locally. The repository includes an MIT license.

Trocker 3.4.1

Trocker's listing and Apache-2.0 repository document broad known-tracker blocking, enhanced Gmail, Yahoo and Outlook.com behavior, tracked-link handling and configurable tracker lists. Its Manifest V3 notes explain that unknown-tracker behavior can differ by webmail proxy.

Mailshade 1.1.0

The official Chrome Web Store listing records Mailshade 1.1.0 as the current public version, confirmed on 2026-08-19, and documents opt-in access for six webmail integrations, reviewed endpoint DNR rules, local event history and supported tracking-link handling. Mailshade separately makes AGPL-3.0-or-later source archives and checksums available; reviewers must match an archive to the exact tested package version before treating it as package evidence.

What source review can and cannot show

A reviewer can inspect declared permissions, rules, client adapters, storage and outbound calls. A source review can also reveal implementation limits worth testing. It cannot replace an executed network test of packaged builds, and license choice is not a performance result.

Current conclusion

All three provide a public code path for review, with different scope and licenses. Relative blocking efficacy, false positives and reliability remain pending under the shared method.

FAQ

Which open-source blockers are covered here?

Mailshade 1.1.0, Trocker 3.4.1 and Ugly Email 4.1.2. Each has a public source location linked in the comparison record; source archives must be matched to the exact tested package version.

Which licenses do they use?

Mailshade makes AGPL-3.0-or-later source archives and checksums available, Trocker's repository is Apache-2.0, and Ugly Email's repository includes an MIT license. A Mailshade archive must be matched to the exact tested package version.

Does open source prove that a blocker is more private?

No. It makes relevant code inspectable. Privacy conclusions still require reviewing the packaged version, permissions, storage and observed network behavior.

Does open source prove stronger blocking?

No. Blocking efficacy and false positives require the same executed fixtures. Those comparative results are pending.

Why are license and product scope reported separately?

A license governs reuse and distribution, while scope describes where the product claims to work. Neither is a substitute for measured protection.