Stirling PDF — An open-core, self-hostable PDF editor with 60+ tools for merging, converting, OCR, and redacting documents without sending files to a third-party cloud.
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Best for: teams and regulated organizations that need to edit, OCR, or redact PDFs without sending files to a third-party cloud service
Pricing: Free for individuals; Server tier starts at $99/month for up to 100 users, Processor runs $0.01/credit after 500 free.
- Stirling PDF is an open-core PDF toolkit with 60+ tools, self-hostable via Docker, desktop app, or air-gapped server.
- The core Editor tier is free with no user limit; source is public on GitHub with 90,000+ stars.
- The Server tier costs $99/month for up to 100 users and adds SSO and team workspaces.
- The Processor tier bills $0.01 per credit after the first 500 credits are free, adding API and webhook automation.
Limitations: Server tier is priced as a 100-user block rather than a low per-seat rate for small teams.; Processor's per-credit billing can produce unpredictable costs for heavy automation.
Top alternatives: Adobe Acrobat, Smallpdf, PDFsam — full list
What is Stirling PDF?
Stirling PDF is an open-core PDF toolkit that bundles more than 60 individual operations — merge, split, compress, convert to/from Word or images, OCR scanned pages, add watermarks, redact text, and apply digital signatures — into one self-hosted application. Unlike Adobe Acrobat or Smallpdf, which process files on the vendor's servers, Stirling PDF's Editor runs entirely on infrastructure the user controls: a Docker container, a downloaded desktop build, or an air-gapped server with no outbound network access. The core Editor is free and its source is public on GitHub, where the project has passed 90,000 stars. Paid tiers layer on top of the same open-source core: Server adds single sign-on and team workspaces for $99/month in blocks of 100 users, and Processor adds API access, webhooks, and automation pipelines billed at a penny per credit after the first 500 are used free. Stirling Tools positions the paid tiers at organizations that need centralized deployment or programmatic document processing rather than a single desktop install.
Stirling PDF is an open-core PDF editing platform built by Stirling Tools that runs on a user's own infrastructure instead of a vendor's cloud, covering more than 60 tools for merging, splitting, converting, OCR, redaction, and e-signing. It ships as a free, source-available Editor for individuals (self-hosted via Docker or a downloaded desktop build), a $99/month Server tier for teams that adds SSO and centralized management in 100-user blocks, and a Processor tier billed at a penny per credit for API and pipeline automation. The project has passed 90,000 GitHub stars and is used inside regulated and air-gapped environments where sending PDFs to a cloud service is not an option.
Standout feature: Self-hosted deployment (Docker, desktop, or air-gapped server) that keeps every PDF operation off vendor infrastructure, backed by a fully open-source core with 90,000+ GitHub stars.
Biggest weakness: The Server tier's $99/month starting price is billed as a flat block for up to 100 users rather than a low per-seat rate, so a small team pays the same as a 100-person deployment; the Processor tier's per-credit billing also makes automation costs hard to predict without checking usage first.
Pros
- Self-hosted deployment options (Docker, desktop, air-gapped) keep sensitive documents off third-party servers.
- Open-source core with 90,000+ GitHub stars and a publicly auditable codebase.
- 60+ tools cover merging, OCR, redaction, and e-signing in one application instead of several point tools.
- Free Editor tier has no user limit or feature paywall for individual use.
Cons
- Server tier pricing is a $99/month block for up to 100 users, not a low-cost single-seat option for small teams.
- Processor's per-credit billing requires monitoring usage to avoid unpredictable automation costs.
- Self-hosting requires comfort with Docker or server administration; there's no fully managed cloud-only free plan.
Stirling PDF pricing
Free tier · paid from $99/mo · verified from the vendor's pricing page
| Plan | Price | Notes |
|---|---|---|
| Editor | Free | Free forever; 60+ PDF tools via web, desktop, or self-hosted Docker deployment; source available on GitHub. |
| Server | $99/mo | Adds single sign-on, team workspaces, and invites; scales in 100-user blocks with centralized billing and tool management. |
| Processor | Custom | Usage-based at $0.01 per credit after the first 500 credits free; adds full API/webhook access, deployable pipelines, and file governance policies. |
| Enterprise | Custom | Custom pricing for regulated environments; air-gapped deployment, SCIM, data residency, and uptime SLAs. |
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