Soup Sieve is a CSS selector library for use with Beautiful Soup 4, designed to select, match, and filter HTML or XML using modern CSS selectors (up through CSS Level 4 drafts, with some limitations). It can replace Beautiful Soup’s built-in select feature and can also be used directly via its API for more controlled parsing.
Project status
- The source (facelessuser/soupsieve) appears actively maintained, with an upstream push on 2026-07-21 and multiple recent updates in late July 2026 (2.9 on 2026-07-19, 2.9.1 on 2026-07-21).
- Apparent update cadence is currently fast (two updates within 2 days, suggesting active development), with additional updates earlier in 2026 (2.8.4 on 2026-05-24) and a long-ish but not alarming historical cadence (most earlier versions are spaced by months).
AI summary generated
Recent updates
2.9.1
Release 2.9.1 fixes attribute substring selector behavior for empty values, specifically for selectors using ^=, $=, and *=. Previously, these cases could match any element that merely had the attribute, instead of matching nothing as required by CSS Selectors Level 4 semantics.
Breaking2.9
Release 2.9 primarily updates Python support, and improves selector processing performance via lazy compilation. It also fixes correctness issues in :nth-child and :nth-last-child for certain An+B boundary cases, and includes parser matching efficiency improvements.
BreakingFeatures2.8.4
Release 2.8.4 contains fixes aimed at preventing pathological selector patterns from causing excessive work, plus a regex-related fix for an inefficient attribute pattern. It also adds a hard cap on the number of selectors processed in a pattern, with new tests covering both normal selectors and custom selectors.
Breaking2.8.3
Release 2.8.3 is described as a fix for an inefficient attribute pattern. The code changes show a rework of the selector parsing regex for attribute selectors, plus an added test covering invalid attribute syntax error reporting.
2.8.2
Release 2.8.2 is described as three small fixes: rejecting non-string keys for custom selectors or namespace dictionaries, correcting `:in-range` and `:out-of-range` behavior at end of year weeks, and fixing a potential infinite loop in a pretty-printing debug function. The release notes do not mention any documentation-site or tooling changes.
2.8.1
Release 2.8.1 is documented as a test-only fix for compatibility with the latest Python HTML parser behavior. However, the provided diff mostly shows documentation site and GitHub Pages publishing workflow changes, with no clear library/runtime code changes in the snippets shown.
2.8
Release 2.8 updates the supported Python versions and changes the PyPI deployment approach. It drops Python 3.8, adds Python 3.14, and switches the publish workflow to PyPI Trusted Publisher.
BreakingFeatures2.7
Release 2.7 documents new support for additional CSS pseudo selectors, specifically adding `:open` and `:muted`, and recognizing a set of other pseudo selectors that require a live browser environment to evaluate. It also notes that previously experimental pseudo-classes are no longer labeled as experimental, plus a small typing fix.
Features2.6
Version 2.6 adds official support for Python 3.13 and implements CSS Nesting Level 1 ampersand scoping (treating `&` as `:scope` when not used in a nesting context). It also improves the error messaging for unrecognized pseudo-classes.
Features2.5
Release 2.5 documents only Python version support changes: adding support for Python 3.12 and dropping support for Python 3.7. The provided code diff, however, appears to be entirely documentation updates, focused on MkDocs/Markdown formatting and content presentation rather than library/runtime behavior.
BreakingFeatures2.4.1
Release 2.4.1 primarily fixes CSS attribute selector parsing so that the case-insensitive flag spacing is optional (a space is allowed but not required). The rest of the diff is largely documentation, typing-only changes, and small build configuration updates.
2.4
Release 2.4 updates Soup Sieve’s selector parsing/matching to track CSS spec changes around :lang() and the handling of forgiving selector lists. It also updates supported Python versions by dropping Python 3.6 and declaring support for Python 3.11.
BreakingFeatures2.3.2.post1
Release 2.3.2.post1 contains documentation updates focused on installation-from-source instructions. The code diff also updates the package version metadata to reflect the post release.