Last checked 2026-10-25 against each tool's own public pages, linked under Sources. Products change; if something here is out of date, write to [email protected]. "Not observed" means we did not find it on the pages we checked, not that it does not exist.
The short version
Most spaced repetition apps ask the same question: when should this card come back? They differ in how they answer. Some use a fixed-interval method, some use a model of memory such as FSRS, and the tools differ in whether that model is the default, an option, or something you tune yourself. The table summarises what each tool's own documentation says.
Scheduling compared
| Tool | Scheduler (as documented) | FSRS | Tuning the model |
|---|---|---|---|
| Cirello | FSRS-6 | Default | Parameters are refit automatically once you have enough reviews |
| Anki | Legacy SM-2 by default | Supported from Anki 23.10, turned on in deck options | "Optimize" button; the manual says once a month is sufficient |
| Mochi | Its own scheduler by default | Optional: choose it in review settings | Default parameters included; you can enter your own and set a target retention |
| RemNote | Several schedulers; FSRS v6 can be enabled | Optional, labelled beta in its help article | Optimizer available after at least 1,000 reviews |
| SuperMemo | Its own "SuperMemo intelligent repetition method" | Not observed | Not observed |
Anki
Anki is the long-standing, free, open-source choice. Its site lists desktop apps for Windows, macOS and Linux, AnkiMobile for iOS and AnkiDroid for Android, free sync through AnkiWeb, support for audio, images, video and scientific markup, and add-ons. Its manual describes FSRS as an alternative to the legacy SM-2 algorithm, enabled globally in deck options, with an Optimize button for the parameters. Anki's strengths are the ecosystem, the add-ons, deck size and platform coverage. If you need those today, Anki has them and Cirello does not.
Mochi
Mochi describes itself as spaced repetition flashcards made easy. It offers apps for Mac, Windows, Linux, iOS and Android plus a web version, a free plan, and a Pro plan at $5 per month on its homepage. Cards are written in Markdown, and the app is local-first. Its documentation says FSRS is an option you switch on in settings, and that reviews stay Remembered or Forgot rather than a four-button scale.
RemNote
RemNote combines notes and flashcards. Its pricing page lists a free plan, Pro at $8 per month ($96 billed yearly) and Pro with AI at $18 per month ($216 billed yearly), with PDF annotation and AI features on the paid plans. Its help center describes FSRS v6 as an option you can enable for all cards or for selected documents, with a note that it is still beta, a desired retention range of 70 to 97 percent, and an optimizer once you have enough reviews. RemNote suits people who want one workspace for notes, documents and cards.
SuperMemo
SuperMemo's own wiki documents successive versions of its scheduling algorithm over many years. Its current app focuses on language courses: its homepage lists iOS, Android and web versions, around 25 languages and nearly 300 courses, and AI tutoring features. It describes its own repetition method; the homepage does not name an algorithm version, and no prices are listed there. SuperMemo suits people who want a guided course rather than a blank deck.
Where Cirello is different, and where it is not
- FSRS-6 is the default, and refitting is automatic. Every Cirello user is scheduled by FSRS-6 with no setting to turn on, and the parameters are refit from your own history once you have enough reviews (at least 1,000 scheduled reviews). On the pages above, the other tools describe optimizing as a manual step or an option.
- Cards that point at a source. A card can prompt from a book, website or image resource plus a short instruction like "page 12". See remembering book highlights.
- A weekly rhythm instead of a daily streak. Progress is counted by the week against a target.
- Ways to review. Reverse, listening, quiz (four options) and mixed sessions, Drill for extra practice on hard cards, exam plans with a date, and a review intensity you set per deck.
- An MCP server for AI assistants, with permissions you choose. See Cirello MCP.
- Behind on purpose-built reach. Cirello is web only today, with iOS and Android apps planned and no date. There are no cloze deletion cards yet, no add-on system, and the library is organised by you in folders and decks. Cards can be read aloud with a synthesized voice, but you cannot upload your own audio, and there is no CSV or deck-file import, only pasting a list. What Cirello can and can't do today keeps this list current.
How to choose
- Choose a mature, extensible tool with mobile apps today: Anki or Mochi.
- Choose one workspace for notes and cards: RemNote.
- Choose a guided language course: SuperMemo.
- Choose a calm web app where FSRS-6 is the default and tuned for you, and review can run from the real source: Cirello.
For the algorithm itself, read what FSRS is and FSRS vs SM-2, or the FSRS app page.
Sources
- Anki: apps.ankiweb.net and deck options manual, retrieved 2026-10-25.
- Mochi: mochi.cards and FSRS documentation, retrieved 2026-10-25.
- RemNote: pricing and FSRS help article, retrieved 2026-10-25.
- SuperMemo: supermemo.com, retrieved 2026-10-25.