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PyPI · #3156 most downloaded on PyPI
Flag engine for the Flagsmith API.
Last release 10 days ago
24 Sep 2026
Release timing varies
gaps range from 1 weeks to 5 months
Nearly every release is documented
notes for 59 of the last 60 stable releases
4 versions withdrawn
withdrawn after publishing
5 years old
82 releases · first in 2021
One column per quarter.
Evaluate flags that depend on other flags
deps: Drop Python 3.9 support, add 3.14, configure updates
include selected variant key in flag results
Exclude identities when PERCENTAGE_SPLIT trait is undefined
Multivariate segment overrides not supported
Implicit identity key not supported for % Split operator
Remove FeatureContext.feature_key , SegmentResult.key
Support generic feature metadata
Use FeatureValue.priority for multivariate evaluations
v7: Remove deprecated APIs, Pydantic models
None identities (#254) (a05befa)string[] as condition value for the IN operator (#255) (68d49d0)Exclude identities when PERCENTAGE_SPLIT trait is undefined
reintroduced-get-identity-segments
## 6.0.0 (2025-07-21) ### ⚠ BREAKING CHANGES * Context values for Segments (#220) (01e7a56) ### Features * Context values for Segments
Nothing published for this version
Nothing published for this version
ImportError when trying to import the TraitValue type
## 5.4.0 (2025-07-21) ### Features * Context values for Segments
add sane model defaults to OrganisationModel and ProjectModel
feat: make map_any_value_to_trait_value public to allow trait value parsing in core by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v5.2.0...v5.3.0
chore(deps-dev): bump black from 23.7.0 to 24.3.0 by @dependabot in https://github.com/Flagsmith/flagsmith-engine/pull/203
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v5.1.1...v5.2.0
fix: Avoid recursion during identity features validation by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/201
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v5.1.0...v5.1.1
feat: remove builders modules by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/195
EnvironmentModel.identity_overrides for the local evaluation mode by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/199Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v5.0.0...v5.1.0
feat: pydantic V2 by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/190
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.1.0...v5.0.0
feat: evaluator module by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/192
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.0.4...v4.1.0
fix: decimal trait values by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/187
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.0.3...v4.0.4
Fix Nan validation by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/184
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.0.2...v4.0.3
fix: restore trait value coercion to string by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/179
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.0.1...v4.0.2
fix: use Config.smart_union to avoid type coercion for TraitModel.trait_value by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/177
Config.smart_union to avoid type coercion for TraitModel.trait_value by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/177Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v4.0.0...v4.0.1
…are kept for backwards compatibility but will be deprecated in the future in favour of Pydantic's .dict() and .parse_obj() methods. It's completely sa…
Support for Python versions earlier than 3.7 is dropped.
This release removes the functionality that supported Flagsmith's Core API <> Edge API interop and migrates the engine model dataclasses to Pydantic, simplifying their serialization.
flag_engine.environments.builders and flag_engine.identities.builders modules are kept for backwards compatibility but will be deprecated in the future in favour of Pydantic's .dict() and .parse_obj() methods. It's completely safe to use them with Flagsmith's EnvironmentModel and IdentityModel instead of builder APIs.
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.6.0...v4.0.0
Ensure percentage split evaluations are consistent in Core API and Local Evaluation by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.5.1...v3.6.0
feat: add Rudderstack support by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/169
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.5.0...v3.5.1
feat: add Project.server_key_only_feature_ids by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/164
Project.server_key_only_feature_ids by @khvn26 in https://github.com/Flagsmith/flagsmith-engine/pull/164Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.4.0...v3.5.0
feat(environment): Add hide_sensitive_data field by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/161
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.3.2...v3.4.0
Update feature state version logic by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/159
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.3.1...v3.3.2
Fix regex evaluations for non string trait values by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/157
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.3.0...v3.3.1
feat(environment): Add name by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/154
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/3.2.0...v3.3.0
Feat(identity/get_hash_key): Add method to help generate consistent mv values by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/1
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.1.0...3.2.0
In segment operator added by @EdsnLoor in https://github.com/Flagsmith/flagsmith-engine/pull/149
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v3.0.0...v3.1.0
feat(identity/update_traits): update return type by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/146
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.3.0...v3.0.0
feat(modulo): Add support for modulo operator by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/144
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.2.0...v2.3.0
Release v2.2.0 by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/142
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.1.2...v2.2.0
Add pip-tools for managing dev requirements by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/138
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.1.1...v2.1.2
Add allow_client_traits field to EnvironmentModel and schema by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/137
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.1.0...v2.1.1
Replace environment webhooks with webhook config by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/134
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.7...v2.1.0
Remove webhooks from _INTEGRATION_ATTS by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/130
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.6...v2.0.7
fix(segment-priority): use priority on evaluation by @gagantrivedi in https://github.com/Flagsmith/flagsmith-engine/pull/128
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.5...v2.0.6
Return updated traits when updating by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/126
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.4...v2.0.5
Add entity_selector to integration model/schema
entity_selector to integration model/schemaFull Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.3...v2.0.4
Fix missing feature_state_value field on dump using engine models
feature_state_value field on dump using engine modelsFull Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.2...v2.0.3
fix(traits/float_value): Add custom field to serialize/deserialize trait_value
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.1...v2.0.2
Add semver to install_requires by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/113
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v2.0.0...v2.0.1
Use feature state is_live by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/111
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v1.6.6...v2.0.0
Use timezone aware datetimes by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/110
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v1.6.5...v1.6.6
Update comments by @matthewelwell in https://github.com/Flagsmith/flagsmith-engine/pull/98
Full Changelog: https://github.com/Flagsmith/flagsmith-engine/compare/v1.6.4...v1.6.5
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