Fit: PartialCore overlap exists; named gaps need replacing or rebuilding.Fit is not feature parity.CTier CDaily-workflow features need a paid editionGNU Affero General Public License v3.0Permissions of this strongest copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. When a modified version is used to provide a service over a network, the complete source code of the modified version must be made available.MayCommercial useModificationDistributionPatent usePrivate useMustLicense and copyright noticeState changesDisclose sourceNetwork use is distributionSame licenseNoLiabilityWarrantySummary from GitHub's choosealicense.comSelf-hostable: yesYou can run it on your own server.
Notion ZIP import preserves page structure; pilot databases, permissions and linked content. Export pages/spaces as Markdown or HTML.
Fit: Different approachSolves the same job differently; plan a redesign, not a copy.Fit is not feature parity.ATier ANo paid feature gates in the self-run editionMIT LicenseA short and simple permissive license with conditions only requiring preservation of copyright and license notices. Licensed works, modifications, and larger works may be distributed under different terms and without source code.MayCommercial useModificationDistributionPrivate useMustLicense and copyright noticeNoLiabilityWarrantySummary from GitHub's choosealicense.comSelf-hostable: yesYou can run it on your own server.
Useful for the wiki/documentation portion of Notion; hierarchical documentation model rather than Notion database workspace. No verified native Notion importer.
Source-available or unresolved
Kept apart: these are not open source by the OSI definition, or their license scope is not settled.
Fit: PartialCore overlap exists; named gaps need replacing or rebuilding.Fit is not feature parity.STier SSource-available license, not OSIBUSL 1.1 (custom license)Not a standard license, so GitHub's license summaries don't cover it. Read the project's license text before relying on it.Self-hostable: yesYou can run it on your own server.
Fits shared documentation; Notion database/workflow parity not claimed. Review BSL Document Service restriction and community edition limits.
Fit: Different approachSolves the same job differently; plan a redesign, not a copy.Fit is not feature parity.UTier ULicense or parity scope unresolvedMIT LicenseA short and simple permissive license with conditions only requiring preservation of copyright and license notices. Licensed works, modifications, and larger works may be distributed under different terms and without source code.MayCommercial useModificationDistributionPrivate useMustLicense and copyright noticeNoLiabilityWarrantySummary from GitHub's choosealicense.comMozilla Public License 2.0Permissions of this weak copyleft license are conditioned on making available source code of licensed files and modifications of those files under the same license (or in certain cases, one of the GNU licenses). Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. However, a larger work using the licensed work may be distributed under different terms and without source code for files added in the larger work.MayCommercial useModificationDistributionPatent usePrivate useMustDisclose sourceLicense and copyright noticeSame license (file)NoLiabilityTrademark useWarrantySummary from GitHub's choosealicense.comAFFiNE EE (custom license)Not a standard license, so GitHub's license summaries don't cover it. Read the project's license text before relying on it.Self-hostable: yesYou can run it on your own server.
Docs and canvas approach; local MIT editor is useful, but full self-hosted collaboration has mixed licensing and seat/plan questions. Pilot database parity and export/import round trips.
Fit: Different approachSolves the same job differently; plan a redesign, not a copy.Fit is not feature parity.UTier ULicense or parity scope unresolvedGNU Affero General Public License v3.0Permissions of this strongest copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. When a modified version is used to provide a service over a network, the complete source code of the modified version must be made available.MayCommercial useModificationDistributionPatent usePrivate useMustLicense and copyright noticeState changesDisclose sourceNetwork use is distributionSame licenseNoLiabilityWarrantySummary from GitHub's choosealicense.comSelf-hostable: yesYou can run it on your own server.
AGPL client supports documents/databases and local data control. Full team replacement needs separately commercial self-hosted services; do not treat AGPL client as unlimited OSS server.
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GNU Affero General Public License v3.0 Permissions of this strongest copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights. When a modified version is used to provide a service over a network, the complete source code of the modified version must be made available. May Commercial useModificationDistributionPatent usePrivate use Must License and copyright noticeState changesDisclose sourceNetwork use is distributionSame license No LiabilityWarranty Summary from GitHub's choosealicense.com Self-hostable: yesYou can run it on your own server. 
