r2-streamer-js implements a basic OPDS feed parser / navigator. Visit this link and enter a public OPDS feed's HTTP URL (see examples below):
https://readium2.herokuapp.com/opds-v1-v2-convert/
The following link is for testing the conversion of OPDS v1 to v2:
https://readium2.herokuapp.com/opds-v1-v2-convert/
The EPUB files referenced from the OPDS feeds are remotely accessed using HTTP partial byte range requests in order to support loading large publications (e.g. audio / video EPUB3 files). More information here: remote-epub.md.
O'Reilly Media http://opds.oreilly.com/opds/ => http://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fopds.oreilly.com%2Fopds%2F
Textos (Spanish) https://textos.info/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Ftextos.info%2Fopds
Gutenberg http://m.gutenberg.org/ebooks.opds/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fm.gutenberg.org%2Febooks.opds%2F
NYPL INSTANT CLASSICS: https://instantclassics.librarysimplified.org/index.xml => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Finstantclassics.librarysimplified.org%2Findex.xml
NYPL OPEN ACCESS: http://oacontent.librarysimplified.org/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Foacontent.librarysimplified.org
NYPL CIRCULATION: https://circulation.librarysimplified.org/ => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fcirculation.librarysimplified.org
LIBRARY FOR ALL: https://books.libraryforall.org/urms => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fbooks.libraryforall.org/urms
FRAMABOOKIN: http://framabookin.org/b/opds/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fframabookin.org%2Fb%2Fopds%2F
QUEBEC LIBRARY: http://quebec.pretnumerique.ca/catalog/root.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fquebec.pretnumerique.ca%2Fcatalog%2Froot.atom
MONTREAL LIBRARY: http://montreal.pretnumerique.ca/catalog/root.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fmontreal.pretnumerique.ca%2Fcatalog%2Froot.atom
FEEDBOOKS: https://www.feedbooks.com/catalog.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fwww.feedbooks.com%2Fcatalog.atom
UNGLUE.IT https://unglue.it/api/opds/ => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Funglue.it%2Fapi%2Fopds%2F
WEB ARCHIVE: http://bookserver.archive.org/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fbookserver.archive.org%2F
SMASHWORDS: http://www.smashwords.com/lexcycle/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.smashwords.com%2Flexcycle%2F
ATRAMENTA: http://www.atramenta.net/opds/catalog.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.atramenta.net%2Fopds%2Fcatalog.atom
PRAGPUB: https://pragprog.com/magazines.opds => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fpragprog.com%2Fmagazines.opds
STANDARD EBOOK: https://standardebooks.org/opds/all => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fstandardebooks.org%2Fopds%2Fall
OPEN EDITION: http://opds.openedition.org => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fopds.openedition.org
REVUES (OPEN EDITION): http://bookserver.revues.org => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fbookserver.revues.org
BOOKS ON BOARD: http://www.booksonboard.com/xml/catalog.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.booksonboard.com%2Fxml%2Fcatalog.atom
HISTORY STATE GOV: https://history.state.gov/api/v1/catalog => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fhistory.state.gov%2Fapi%2Fv1%2Fcatalog
TUEBL.CA: http://tuebl.ca/catalog/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Ftuebl.ca%2Fcatalog%2F
SLUCAS.FR: http://cops-demo.slucas.fr/feed.php => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fcops-demo.slucas.fr%2Ffeed.php
FBREADER ARMENIAN: http://armebooks.fbreader.org/books/index.xml => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Farmebooks.fbreader.org%2Fbooks%2Findex.xml
EBOOKS GRATUITS: http://www.ebooksgratuits.com/opds/feed.php ==> https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.ebooksgratuits.com%2Fopds%2Ffeed.php
MANY BOOKS: http://manybooks.net/opds/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fmanybooks.net%2Fopds%2F
eFORGE: http://eforge.eu/OPDS/_catalog/index.xml => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Feforge.eu%2FOPDS%2F_catalog%2Findex.xml
EBOOK BIKE: https://ebook.bike/catalog => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Febook.bike%2Fcatalog
WOLNELEKTURY: http://www.wolnelektury.pl/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.wolnelektury.pl%2Fopds
MEK.OSZK.HU: http://bookserver.mek.oszk.hu => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fbookserver.mek.oszk.hu
FLIBUSTA.NET http://proxy.flibusta.net/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fproxy.flibusta.net%2Fopds
LITRES RU: http://opds.litres.ru/ => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fopds.litres.ru%2F
CHITANKA: http://chitanka.info/catalog.opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fchitanka.info%2Fcatalog.opds
GITBOOK: https://api.gitbook.com/opds/catalog.atom => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fwww.gitbook.com%2Fapi%2Fopds%2Fcatalog.atom%20
LIB RUS EC: http://lib.rus.ec/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Flib.rus.ec%2Fopds
ZONE 4 IPHONE: http://www.zone4iphone.ru/catalog.php => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.zone4iphone.ru%2Fcatalog.php
FLASCHENPOST: https://flaschenpost.piratenpartei.de/catalog/ => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fflaschenpost.piratenpartei.de%2Fcatalog%2F
ANARCHIST LIB: https://theanarchistlibrary.org/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Ftheanarchistlibrary.org%2Fopds
AOZORA http://aozora.textlive.net/catalog.opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Faozora.textlive.net%2Fcatalog.opds
PRESTIGIO PLAZA http://ebooks.prestigioplaza.com/feed => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Febooks.prestigioplaza.com%2Ffeed
BNF.FR (GALLICA): http://gallica.bnf.fr/opds => https://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fgallica.bnf.fr%2Fopds
CULTURETHEQUE (ARCHIMEDE): https://www.culturetheque.com/exploitation/GBR/Portal/Recherche/Search.svc/Catalog => https://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fwww.culturetheque.com%2Fexploitation%2FGBR%2FPortal%2FRecherche%2FSearch.svc%2FCatalog
OPOTO-ED: http://opoto-ed.org/catalogue/opds => http://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fopoto-ed.org%2Fcatalogue%2Fopds
WMFLABS WIKISOURCE: https://tools.wmflabs.org/wsexport/wikisource-fr-good.atom => http://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Ftools.wmflabs.org%2Fwsexport%2Fwikisource-fr-good.atom
Blah http://blah.me/opds/index.atom => http://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fblah.me%2Fopds%2Findex.atom
CBeta http://www.cbeta.org/opds/ => http://readium2.herokuapp.com/opds-v1-v2-convert/http%3A%2F%2Fwww.cbeta.org%2Fopds%2F
CEL desLibris https://api.deslibris.ca/api/feed => http://readium2.herokuapp.com/opds-v1-v2-convert/https%3A%2F%2Fapi.deslibris.ca%2Fapi%2Ffeed
Specification: https://drafts.opds.io/opds-2.0
Sample feed: https://test.opds.io/2.0/home.json => http://readium2.herokuapp.com/opds-v2-browse/https%3A%2F%2Ftest.opds.io%2F2.0%2Fhome.json
Feedbooks: https://catalog.feedbooks.com/catalog/index.json (replace .json with .atom to access the OPDS1 XML feed) => http://readium2.herokuapp.com/opds-v2-browse/https%3A%2F%2Fcatalog.feedbooks.com%2Fcatalog%2Findex.json
Lirtuel.be: https://www.lirtuel.be/v1/home.opds2 => http://readium2.herokuapp.com/opds-v2-browse/https%3A%2F%2Fwww.lirtuel.be%2Fv1%2Fhome.opds2
CantookStation / Pretnumerique.ca / Bibliopresto.ca: https://missmills.cantookstation.com/v1/home.opds2 and http://quebec.pretnumerique.ca/v1/home.opds2 and http://montreal.pretnumerique.ca/v1/home.opds2 and https://demoreader.cantookstation.com/v1/home.opds2 and https://demo-testapp.cantookstation.com/v1/home.opds2 and ... many more, see https://sols.cantookstation.com/find_library and http://www.pretnumerique.ca/find_library and https://bibliopresto.ca => http://readium2.herokuapp.com/opds-v2-browse/
NYPL registry: https://libraryregistry.librarysimplified.org/libraries => http://readium2.herokuapp.com/opds-v2-browse/https%3A%2F%2Flibraryregistry.librarysimplified.org%2Flibraries
Aldiko registry: http://libraries.aldiko.com/home.json => http://readium2.herokuapp.com/opds-v2-browse/http%3A%2F%2Flibraries.aldiko.com%2Fhome.json