Open Source Contract Management
Contracts are legal records first and documents second, so the questions that matter are who signed, when, and whether the signature would survive a challenge - which is why the audit trail and signing logic deserve more scrutiny than the editor. The open source options here run document signing and contract lifecycle on your own servers, keeping signed PDFs, the cryptographic proof of signing, and the renewal and expiry tracking in storage you control rather than a vendor's vault.

DocuSeal
Open source document filling and signing for PDF forms, e-signatures, and verification

Documenso
Open source document signing for digital signatures, workflows, and reusable templates

OpenSign
Open source PDF e-signing with templates, multi-signer flows, and audit trails

Wraft
Open-source document lifecycle management for drafting, collaborating, and distributing documents