# Open-source e-signature APIs and signing libraries There are two kinds of tool here. DocuSeal, Documenso, OpenSign and LibreSign are full signing platforms. You upload a document, add signers and send it, and their docs describe an API for doing that from your own app. pyHanko, endesive and the EU's DSS are developer libraries that add certificate signatures to PDFs inside your code, with no sending or tracking. Open PDF Sign and JSignPdf sit between the two, as a command-line tool and small server. Several platforms are AGPL or keep some features in a paid edition, so check the commercial-use column before building a product on one. > We track 9 open-source e-signature platforms and signing libraries, each checked for licence, commercial use, hardware, paid services and setup. pyHanko runs on your own machine, allows commercial use and needs no paid service. Easiest to set up: pyHanko, JSignPdf and endesive (and 1 more). Facts checked 2026-11-07. Give this to your agent: "Help me with this: "Open-source e-signature APIs and signing libraries", using the RepoQuarry guide at https://repoquarry.dev/guides/open-source-esignature-api.md. Read the whole guide first, including its builds and links. Recommend the option that fits what I am building and why, check each project's official docs (linked there) before installing anything, ask me before spending money or using my accounts, and tell me what you set up when you finish." ## Best for… - **Easiest to start:** [pyHanko](https://repoquarry.dev/projects/pyhanko.md). Setup rated easy: Easy; pip install with optional extras for PKCS#11, images, fonts and the CLI - **Nothing to pay for:** [OpenSign](https://repoquarry.dev/projects/opensign.md). No paid service required: None required for self-hosting; README describes a free cloud-hosted version - **Business use:** [pyHanko](https://repoquarry.dev/projects/pyhanko.md). Permissive MIT licence, commercial use confirmed - **Windows:** [DSS (Digital Signature Service)](https://repoquarry.dev/projects/eu-dss.md). Documented to run on Windows, Linux - **Most popular:** [DocuSeal](https://repoquarry.dev/projects/docuseal.md). 19,045 GitHub stars, the most in this list ## Compared Ordered by our ranking: stars 40%, recent activity 30%, sourced facts 30%. | Project | Runs locally | Commercial use | Paid services | Setup | Platforms | |---|---|---|---|---|---| | [DocuSeal](https://repoquarry.dev/projects/docuseal.md) | Yes | Conditions · AGPL-3.0-only | Optional only | Medium | Not confirmed | | [Documenso](https://repoquarry.dev/projects/documenso.md) | Yes | Conditions · AGPL-3.0-only | Optional only | Medium | Not confirmed | | [OpenSign](https://repoquarry.dev/projects/opensign.md) | Yes | Conditions · Custom licence | None required | Medium | Windows, macOS, Linux | | [DSS (Digital Signature Service)](https://repoquarry.dev/projects/eu-dss.md) | Yes | Conditions · LGPL-2.1-only | None required | Hard | Windows, Linux | | [pyHanko](https://repoquarry.dev/projects/pyhanko.md) | Yes | Yes · MIT | None required | Easy | Windows, macOS, Linux | | [JSignPdf](https://repoquarry.dev/projects/jsignpdf.md) | Yes | Conditions · MPL-2.0 OR LGPL-2.1-only | None required | Easy | Windows, macOS, Linux | | [LibreSign](https://repoquarry.dev/projects/libresign.md) | Yes | Conditions · AGPL-3.0-or-later | None required | Medium | Not confirmed | | [endesive](https://repoquarry.dev/projects/endesive.md) | Yes | Conditions · MIT AND LGPL-3.0-only | None required | Easy | Windows | | [open-pdf-sign](https://repoquarry.dev/projects/open-pdf-sign.md) | Yes | Conditions · Apache-2.0 AND LGPL-2.1-only | None required | Easy | Not confirmed | ## Common questions ### Is there a free alternative to the DocuSign API? Yes. OpenSign, DSS (Digital Signature Service), pyHanko, JSignPdf, LibreSign and endesive (and 1 more) need no paid service at all. DocuSeal and Documenso are free to run, with paid services optional or depending on your setup. The software is free; what you may pay for is the server it runs on and any outside service it relies on, which the paid-services column lists. ### Does DocuSign have an API? Yes. DocuSign's eSignature REST API lets your own app request signatures, automate forms and track documents; its docs describe more than 400 endpoints. The open-source tools here give you a signing API you host yourself instead. (source: https://developers.docusign.com/docs/esign-rest-api/) ### Can I self-host an e-signature API? 6 of the 9 can run on your own server: DocuSeal, Documenso, OpenSign, DSS (Digital Signature Service), LibreSign and open-pdf-sign. DocuSeal, Documenso and OpenSign document a Docker setup. Setup is rated easy for open-pdf-sign. ### What server does a self-hosted e-signature tool need? Memory stated in their docs: 1 GB for Documenso. The others give no single figure. Each project page quotes the source and says whether a figure is a minimum or a recommendation. ### Which can I use in a commercial product? Confirmed: pyHanko (MIT). With conditions: DocuSeal, Documenso, OpenSign, DSS (Digital Signature Service), JSignPdf, LibreSign, endesive and open-pdf-sign. This is not legal advice; read each licence. ### Which is easiest to set up? Rated easy from their install docs: pyHanko, JSignPdf, endesive and open-pdf-sign. Each page links the exact install step we checked. ### Which run on Linux? OpenSign, DSS (Digital Signature Service), pyHanko and JSignPdf are documented to run on Linux. The others are web apps, servers or unconfirmed; check each page. ## By paid product - [Open-source alternatives to DocuSign](https://repoquarry.dev/alternatives/docusign.md) - [Open-source alternatives to Dropbox Sign](https://repoquarry.dev/alternatives/dropbox-sign.md) - [Open-source alternatives to PandaDoc](https://repoquarry.dev/alternatives/pandadoc.md) --- Source: RepoQuarry (https://repoquarry.dev/guides/open-source-esignature-api). Data licence: CC BY 4.0. Quotes are from project documentation and belong to their authors.