Tesseract Censorship Blacklist Controversy
A controversy surrounding Tesseract's inclusion of a hardcoded blacklist targeting leftist and trans-friendly instances and users.
July 2026
db0 Posted PSA Regarding Tesseract's Hardcoded Blacklist
db0 posted a Public Service Announcement detailing a blacklist of 32 instance domains compiled directly into Tesseract. This list was inaccessible to administrators.
Canyon201 discovers hardcoded blacklist in Tesseract frontend
Canyon201 discovered the hardcoded hidden instance blacklist after upgrading the Tesseract frontend. The frontend subsequently displayed an 'incompatible with that instance' message when connecting to blacklisted servers.
Source ↗Tesseract developer implements hidden instance blacklist
The developer of the Tesseract frontend added an explicit, unmodifiable blacklist. This blacklist included instances categorized as leftist and trans-friendly.
Source ↗Tesseract frontend upgrade introduced hardcoded instance blacklist
The Tesseract frontend was upgraded, which included the addition of a hardcoded, unmodifiable blacklist. This blacklist targeted instances deemed leftist and trans-friendly.
Source ↗Tesseract frontend developer implements hardcoded instance blacklist
The developer of the Tesseract frontend added an explicit, unmodifiable blacklist within the software. This blacklist targets instances deemed leftist or trans-friendly.
Source ↗Quokka discovers Tesseract blacklist after frontend upgrade
Quokka discovered the hardcoded blacklist after upgrading the Tesseract frontend. The software displayed a message stating it was 'incompatible with that instance' when connecting to blacklisted servers.
Source ↗Quokka forks Tesseract and disables the blacklist
Quokka created a fork of the Tesseract repository and subsequently disabled the hardcoded blacklist within the code. The author expressed doubt about maintaining the modified frontend.
Source ↗Canyon201 forks Tesseract and disables the censorship blacklist
Canyon201 forked the Tesseract repository. The fork included modifications to disable the hardcoded blacklist feature.
Source ↗User forked Tesseract and disabled the blacklist
A user forked the Tesseract project and subsequently disabled the hardcoded blacklist. This action was taken in response to the developer's inclusion of the blacklist.
Source ↗YSK Implements Blacklist Filtering for Lemmy Users
YSK, the developer of Tesseract, created a blacklist targeting Lemmy users. This list causes users to be filtered when accessing content via the Tesseract Frontend.
Source ↗Tesseract Frontend Downloads Blacklist Plaintext Over HTTP
The Tesseract Frontend downloads the blacklist in plaintext over HTTP when it boots. This mechanism allows the developer to silently update the list without requiring user action.
Source ↗Tesseract Frontend Utilizes User Regex for Cross-Instance Filtering
The Tesseract Frontend incorporates a user regex section that enables filtering policies to be applied across multiple Lemmy instances.
Source ↗Tesseract Fetches Unauthenticated Censorship Policy at Runtime
Tesseract downloads a second, unauthenticated filter policy over HTTP upon loading. This policy contains 552 user accounts, 2,275 username patterns, and 351 domains set to hide matches.
Tesseract Filters Specific Communities and Keywords
The Tesseract frontend actively filters content, including communities like lemmy.sdf.org/c/modabuse and keywords such as comrade and ACAB. This filtering is implemented via the runtime policy.