unglue (v. t.) 1. To pay an author or publisher for publishing a Creative Commons ebook.
unglue (v. t.) 2. To make a digital book free to read and use, worldwide.
unglue (v. t.) 3. To make it legal for a digital book to be used, distributed, archived and preserved by libraries.
unglue (v. t.) 4. For an author or publisher, to accept a fixed amount of money from the public for its unlimited use of an ebook.
unglue (v. t.) 5. To make your favorite books free to everyone on earth.
unglue (v. t.) 6. To reward authors and publishers for sharing books with the world.
Learn more

Find over 10,000 free ebooks here.
Help us make more ebooks free!

Creators make ebooks in EPUB, MOBI, and PDF.
Ungluers love them for doing it.
Creators apply Creative Commons licenses to ebooks.
Ungluers read them at home, at a library, anywhere.
Creators ask downloaders to contribute what they choose.
Ungluers say thank you with their support.
Creators make ebooks in EPUB.
Ungluers love them for doing it.
Creators set a funding goal and a per-copy price.
Ungluers purchase the ebook to advance the campaign.
When the funding goal is met, Creative Commons licenses are automatically applied.
Creators set a funding goal and rewards for supporters.
Ungluers pledge to support the campaign.
When the campaign succeeds, We collect Ungluer pledges.
The ebook is created and rewards are distributed.
Creative Commons licenses are applied.
Ungluers read them at home, at a library, anywhere.

API Help

Some of the data from is avaiable via a JSON API. You will need a key and username to be able to use the API.

Please sign in first.

Ebook Widgets

You don't need an API key to embed Ebook (HTML) widgets.

Here's a widget that displays's featured ebook - it changes most every day! Copy/paste this into your site:
If your website doesn't allow javascript (wordpress blogs, for example) you can use the no-script version. Copy/paste this into your site:
featured book cover
Today's Free Ebook at
Here's a sample widget for the book Riverwatch with ISBN 9780743480406: Copy/paste this into your site:

Basic API info

Available Resources (JSON)

Resources on this list can be accessed via{resource_on_list}/?format=json&api_key={your_api_key}&username={your_username} .

Works can be ordered by how often they've been favorited; append &order_by=num_wishes (ascending) or &order_by=-num_wishes (descending).

Free Ebooks by ISBN

With an API key, you can check if there's a free ebook for any ISBN. ISBNs can be 10 or 13 digits, and can include dashes. This service returns all free-licensed ebooks for a work associated with an ISBN, and for each ebook includes information about file type, rights, and the provider hosting the file.

For example, here's how to get a list of ebook files for "Homeland".

(Log in to see links)

Identifier Resolution

Here's how to get use the api to find related identifiers:

    Do a query on your identifier.

    Here's how to get identifiers for an isbn:

  • (Log in to see links)

    In addition to 'isbn', you can use 'goog' if you have a google books id, 'doab' for DOAB handles (like '20.500.12854/97310'), 'doi' for Digital Object identifiers (like '10.3390/books978-3-0365-6176-9', and 'oclc' for oclc numbers.

    Now you'll have URIs for an work id and (possibly) one or more edition ids.

  • Use the work id's (or the edition ids if you're feeling selective) to find all the associated identifiers.:

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OPDS Catalog Feeds

We have a basic implementation of OPDS feeds. You don't need a key to use them. The starting point is Use the page parameter to page through the results.


filtered by format
filtered by license
filtered by title search
filtered by keyword
filtered by ungluer
filtered by having a Project Gutenberg or DOAB identifier (doab, gtbg)

There's also an OPDS record available for every work on For example, requesting, get you to the web page or opds record for A Christmas Carol.

ONIX Catalog Feeds

There is an ONIX 3.0 feed corresponding to every facet of our free ebook lists. You don't need a key to use them. There is a maximum of 100 books per result you can change with the max parameter. For example, here are the first twenty CC BY-ND-ND licensed books available in EPUB. Pages of 30 records each are available via the page parameter. Here's the first page of books from the Directory of Open Access Books.

There's also an ONIX record available for every free ebook on For example, here is Issues in Open Research Data.

Identifiers with Content type negotiation

There's a URI to identify every work used in OPDS feeds. HTTP content negotiation is used for these ids, so requesting application/atom+xml;profile=opds-catalog;kind=acquisition for get you to the web page or opds record for A Christmas Carol. requesting text/xml gets you the onix record. Otherwise, you get the normal html page.