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Libraries · head to head

FOLIO vs Sigil

FOLIO logo

FOLIO

Libraries

The open source library services platform reimagined

From
Free
Rated
-
Full reviewWebsite
Sigil logo

Sigil

Publishing

Open source EPUB editor for working directly on the file, not generating it

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: FOLIO fOLIO is open source with no vendor-run SaaS from the FOLIO project itself; adopters must self-host or contract a third-party hosting partner separately.; Sigil it produces no print output whatever, so any book that needs a paperback interior requires a completely separate tool and a second workflow.
  • They diverge on capability: FOLIO covers Modular app architecture, Sigil covers Direct EPUB editing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which FOLIO and Sigil actually diverge.

Attributes where FOLIO and Sigil differ
AttributeFOLIOSigil
Pricing modelopen-sourceOpen source, no licence fee
PlatformsWeb, ApiWindows, macOS, Linux
CategoryLibrariesPublishing
Founded2016Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in FOLIO

  • Modular app architecture
  • Circulation and check-out
  • Inventory and cataloging
  • Acquisitions and invoicing
  • Electronic resource management
  • User management
  • Agreements and licenses
  • Course reserves

Only in Sigil

  • Direct EPUB editing
  • Code and preview views
  • EPUB 2 and EPUB 3
  • Regex across files
  • Validation
  • Python plugins

What people use each for

The jobs each tool is most often brought in to do.

FOLIO

  • Academic library managementnot Sigil
  • Custom library applicationsnot Sigil
  • Consortial systemsnot Sigil
  • Electronic resource managementnot Sigil

Sigil

  • Fixing an EPUB that a retailer validator has rejected, without re-exporting from the tool that generated itnot FOLIO
  • Correcting the table of contents, reading order or metadata in a file supplied by a conversion servicenot FOLIO
  • Preparing a back-catalogue title where the only surviving source is the EPUB itselfnot FOLIO
  • Applying a consistent stylesheet or a bulk text correction across every chapter of a book at oncenot FOLIO

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

FOLIO

  • FOLIO is open source with no vendor-run SaaS from the FOLIO project itself; adopters must self-host or contract a third-party hosting partner separately.

Sigil

  • It produces no print output whatever, so any book that needs a paperback interior requires a completely separate tool and a second workflow.
  • Meaningful use requires reading and writing HTML and CSS, which puts it out of reach of most authors who simply want a finished file.
  • There is no cloud storage, sync or collaboration, so the book exists as a file on one machine and version control is whatever you set up yourself.
  • Development depends on a small number of volunteer maintainers, so release timing and platform builds follow their availability rather than a roadmap, and a lapse in maintenance would leave no obvious successor.
  • It provides no distribution, no retailer connection and no Kindle-native output, so it sits in the middle of a workflow that other tools have to complete on both sides.

Pricing, plan by plan

FOLIO

Free
  • Community EditionFree
    • Modular app ecosystem
    • Circulation management
    • Cataloging
  • Hosted (via EBSCO/Index Data)$undefined/year
    • Everything in Community
    • Managed hosting
    • Professional support

Sigil

Free
  • SigilFree
    • GPL licensed with no cost or account required
    • Full functionality with no feature gating
    • Community support through forums and the issue tracker

Which should you pick?

Choose FOLIO if

  • You need modular app architecture.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want circulation and check-out.
FOLIO review

Choose Sigil if

  • You need direct epub editing.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want code and preview views.
Sigil review

Questions people ask

Is FOLIO or Sigil better?
Neither clearly leads. FOLIO starts at Free and Sigil at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, FOLIO or Sigil?
FOLIO starts at Free and Sigil at Free.
Does FOLIO or Sigil run on more platforms?
FOLIO runs on Web, Api. Sigil runs on Windows, macOS, Linux.
Can I use FOLIO for free?
Both have a free tier, so you can try either at no cost before committing.
What is FOLIO best used for?
FOLIO is most often used for academic library management, custom library applications, consortial systems, electronic resource management. Of those, academic library management and custom library applications are not what Sigil is typically brought in for.
What can FOLIO do that Sigil cannot?
FOLIO covers Modular app architecture, Circulation and check-out, Inventory and cataloging, Acquisitions and invoicing. Sigil covers Direct EPUB editing, Code and preview views, EPUB 2 and EPUB 3, Regex across files.

Answered from the vendors’ own pages

FOLIO: Is Folio free to use?

Yes, Folio is an open source library services platform built through community collaboration, with no licensing fees for the software itself.

Source
Sigil: Can I write my book in Sigil?

You can, but you should not. It is an EPUB editor, not a word processor, and writing long-form prose in it is unpleasant. Write elsewhere, import, then finish in Sigil.

FOLIO: Is Folio free for commercial use?

Folio is open source software with no inherent restrictions on commercial use, though the specific license terms should be reviewed for your use case.

Source
Sigil: Does it make Kindle files?

Not natively. Produce a valid EPUB in Sigil and let Amazon convert it, or use a separate conversion tool for other Kindle formats.

FOLIO: Is there professional support available for Folio?

The website does not specify whether paid support contracts or professional services are available for Folio implementation and maintenance.

Source
Sigil: Is it safe to rely on a volunteer project for commercial work?

The files it produces are standard EPUB, so nothing is locked in. The risk is that maintenance stops, not that your books become unreadable.

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