Highlight Aggregators (Readwise)

The highlights you make in Kindle / Kobo / Apple Books / web articles are only valuable if you can search them later. The FOSS path — KOReader → Obsidian — gives you the same compounding "daily highlights" workflow as Readwise without the SaaS dependency. Readwise is the polished paid pick. Pair with spaced repetition / Anki, research / Zotero, KOReader, and read-it-later.

Self-host & FOSS first

• ★ ★ KOReader Markdown export → Obsidian / Logseq — free OSS end-to-end; KOReader exports highlights as Markdown / JSON / HTML; the Obsidian KOReader plugin auto-imports from a connected device. The default FOSS pipeline. See KOReader.
• ★ ★ Hypothesis (h) — BSD; free; collaborative web annotation; Chrome / Firefox extensions; PDF support; the OSS academic-and-classroom standard. Self-hostable.
  • https://github.com/hypothesis/h
• ★ Obsidian highlights plugins — free + paid; Obsidian Annotator, Reading Highlights, Kindle Highlights, Make.md. Pull My Clippings.txt from Kindle, parse, drop into Obsidian.
• ★ Logseq highlights — free OSS; same idea; outliner-flavoured.
• calibre-highlights-export — community Calibre plugin; bulk export from Calibre's reader.
• My Clippings.txt — the universal Kindle export (USB → text file → script → Markdown). Free.
• Bookcision — free bookmarklet; scrapes Kindle Cloud Reader highlights into JSON.

Readwise (paid hosted — secondary)

• ★ Readwise — paid (~$8/mo, ~$60/yr; cheaper for students); aggregates highlights from Kindle, Kobo, Apple Books, Google Play Books, Hypothesis, Twitter / X, Pocket, Instapaper, Matter, Airr, Snipd (podcasts), Supplemental Whisper transcripts, web (Readwise Reader), PDF / EPUB (via Reader), Goodreads import. Daily-review email + spaced-repetition. Exports to Notion, Obsidian, Logseq, Roam, Evernote, Markdown. Sync APIs for everything. The single best paid argument if you don't want to glue scripts together.
  • https://readwise.io
• ★ Readwise Reader is bundled with Readwise — see Read-It-Later.
• Bookfusion — paid + free tier; ebook + highlight aggregator; lighter Readwise alternative.

Web annotation (highlight + comment on any page)

• ★ Hypothesis — see above; the academic default.
• Glasp — free; YouTube transcripts + web highlights; social-flavoured ("see what others highlighted"); AI summaries.
• Liner — paid + free; web + PDF highlighting; AI summaries.
• Diigo — paid + free; long-running; older UI; legacy.
• Memex (WorldBrain) — open source; web annotation + bookmarking; smaller community in 2026.

Kindle highlights specifically

• ★ My Clippings.txt — every Kindle stores highlights in documents/My Clippings.txt; plug in via USB and copy. Free.
• ★ Readwise Kindle import — automatic via OAuth.
• Bookcision — bookmarklet; scrapes Kindle Cloud Reader highlights into JSON.
• Klib — paid Mac; clippings parser + Apple Books reader.

Highlights → Anki / spaced repetition pipeline

• ★ Readwise → Anki — Readwise has a built-in "Mastery" mode; export to Anki via the Readwise → Anki community add-on.
• Readwise → RemNote / Mochi — first-class integrations.
• Obsidian + Spaced Repetition plugin — the FOSS pipeline; flag highlights, generate cards.
• See Spaced Repetition (Anki).

Patterns

• ★ Highlight in the moment, review later. The killer feature of Readwise is the daily email of 5 random old highlights. Compounding interest on books you read 5 years ago.
• One destination, many sources. Readwise has 30+ source integrations; the FOSS path requires more glue. Pick one or commit to scripts.
• Markdown export = portable forever. Whatever you use, export to Markdown periodically.
• Tag your highlights — "favorite", "to-share", "to-cite", "anki" — searchable later.

Pick this if…

• Default FOSS, Markdown-first: Obsidian + KOReader + community plugins.
• Academic / classroom annotation, self-hostable: Hypothesis.
• YouTube + web, free: Glasp.
• Default paid, just-works: Readwise (+ Reader).
• Research workflow: Hypothesis + Zotero.