Open-source Nitro PDF alternatives

Stirling PDF is an open-source PDF editing platform that can run as a desktop app, in the browser, or on servers you control through a private API. The project's pitch is that documents can be edited, signed, redacted, converted and automated without being sent to an external service. It is written in Java and distributed with Docker for self-hosting.

It bundles more than 50 PDF tools, including merge, split, sign, redact, convert, OCR and compress. No-code pipelines in the interface let you automate repeated processing, and REST APIs cover nearly all tools for integration into existing systems. The interface is available in over 40 languages. Enterprise options include SSO, auditing and flexible on-premise deployments.

A quick start with Docker serves the app on a local port, and the documentation covers desktop and Kubernetes installs. The repository describes the project as open-core, and GitHub lists its license as 'Other', so confirm which features fall under which terms. It suits individuals and organizations that handle sensitive PDFs and prefer a self-hosted alternative to online PDF tools.

DocuSeal is an open-source platform for filling and signing documents online. Users build PDF forms with a visual field builder and send them to be completed and signed on any device through a mobile-optimized web interface. It is presented as an open-source alternative to DocuSign.

The builder offers 12 field types, including signature, date, file and checkbox, and a document can have multiple submitters. DocuSeal sends automated emails over SMTP, applies automatic PDF e-signatures and verifies PDF signatures. Files can be stored on disk or in AWS S3, Google Storage or Azure, and an API and webhooks support integrations. The interface ships in 7 languages, with signing available in 14.

The core is released under AGPL-3.0 and built with Ruby on Rails, Vue and Tailwind CSS. It can be deployed with Docker, using SQLite by default or PostgreSQL and MySQL through a database URL setting, and one-click options exist for Heroku, Railway, DigitalOcean and Render. Paid Pro features include white-labeling, SSO/SAML, bulk send and embedded signing, and a hosted cloud version is available.

BentoPDF is a client-side PDF toolkit that handles files directly in the browser, so documents are never uploaded to a server. That design makes it attractive for sensitive paperwork, and it can also be self-hosted. You can merge, split and reorganize pages, edit and modify PDFs, convert images and other formats to PDF, convert PDFs to other formats, and secure or optimize files.

Deployment is flexible. The project documents static hosting, local self-hosting, Docker Compose and Podman, a Podman Quadlet setup and a simple self-hosted build mode, along with options for custom branding, disabling specific tools and removing the GitHub star counter. It also covers WebAssembly configuration, air-gapped or offline deployment, a CORS proxy for digital signatures, and version management. A commercial build is mentioned, and the interface is translated into multiple languages.

BentoPDF is licensed under AGPL-3.0, with commercial licensing noted in the documentation, and it is written in JavaScript and TypeScript. It suits individuals, teams and organizations that need a free alternative to online PDF tools without sending files to third parties.

Documenso is an open-source alternative to DocuSign for signing documents digitally. Its stated aim is to build trust by letting people self-host the software and review how it works, rather than relying on a closed signing provider. It is released under the AGPL-3.0 license.

The product lets teams create templates, build signing workflows and integrate signing into other systems. Repository topics mention PDF signatures, digital signatures following the PAdES standard, e-signatures, PostgreSQL and Prisma. The README lists a stack of TypeScript, React Router v7, Hono, Prisma and Tailwind CSS with shadcn/ui and Radix UI components.

You can try it by self-hosting or by signing up on documenso.com, and an Enterprise plan is offered to large organizations that need extra flexibility and control. The maintainers have paused external pull requests apart from a small group of trusted contributors and ask for detailed issues instead, while keeping the code open to read, audit, run and fork.