RxMarbles vs Siftmind
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RxMarbles
Visualize and understand ReactiveX observable sequences with interactive diagrams. This educational tool helps developers grasp complex asynchronous programming concepts by illustrating event-based data streams and composition operators.
- Interactive observable diagrams
- Visualization of event streams
- Demonstration of composition operators
- Educational tool for asynchronous programming
- Explains observer pattern extensions
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Interactive diagrams of Rx Observables. ReactiveX is a library for composing asynchronous and event-based programs by using observable sequences. It extends the observer pattern to support sequences of data and/or events and adds operators that allow you to compose sequences together declaratively while abstracting away concerns about things like low-level threading, synchronization, thread-safety, concurrent data structures, and non-blocking I/O.
Siftmind
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One idea from a book. One step you take today. Siftmind is a daily practice built on good nonfiction. Each day you talk one idea through in about 5 minutes, then take one small step in your own life. Day after day, it adds up to 67 days of things you actually did. PICK A CHALLENGE • Redemption: let go of what doesn’t matter and rebuild, one day at a time. With Dan, who was laid off and got back on his feet. • Confident Leader: stop doing your team’s work and start leading it. With Pete, who did his team’s work for two years. • Charisma: be the person people want to keep talking to. Ask better questions, listen to the end, tell a story people remember. Each challenge runs 67 days, with stops at Day 7 and Day 28 to look back. HOW A DAY WORKS • The Sift: about 5 minutes. One idea, a scene from a week like yours, and a question only you can answer. With voice or quiet, at your pace. • Your step: one thing to do today, in 15 minutes or less. Mark it kept, or move it to tomorrow. • Your Notebook: the lines you keep from each Sift, week by week, in your own words. If a day slips, nothing resets. Yesterday’s Sift is still there. We’ll remind you once a day, at the time you pick. Each Sift credits the book and the author it comes from. The people you meet in each challenge are characters, written from the stories of real people. SUBSCRIPTION Siftmind needs a subscription, billed monthly or yearly. Payment is charged to your Apple ID when you confirm the purchase. It renews automatically unless you cancel at least 24 hours before the end of the current period, and your account is charged for the renewal within 24 hours before the period ends. You can manage or cancel it any time in your App Store account settings. Terms of Use: https://app.notion.com/p/Terms-of-Use-3c6b47d46ebe80c4b340c84e2013ba75 Privacy Policy: https://app.notion.com/p/Privacy-Policy-3c6b47d46ebe804c8036df3668e82448
Screenshots
Verdict
The clearest difference is in-app purchases: RxMarbles at none against Siftmind's 2. RxMarbles also leads on device support (3 vs 1) and iOS requirement (9.2 vs 18.0). Siftmind's advantage is update cadence (monthly vs every 4 months). On price and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Siftmind sells 2 in-app purchases, starting at $9.99 per month. RxMarbles asks for nothing beyond the download.
RxMarbles ships an update every 4 months, Siftmind monthly. The most recent releases landed on November 2, 2026 and November 7, 2026 respectively.
| Parameter | RxMarbles | Siftmind |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (16 ratings) — better | — |
| Positive reviews | 86.2% of reviews | — |
| Number of ratings | 16 — better | — |
| Update frequency | Every 4 months | Monthly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 9.2 — better | 18.0 |
| Further details — not scored | ||
| Size | 21 MB | 26 MB |
| Age rating | 4+ | 12+ |
| Developer | AnjLab | Oleksandr Yaroshenko |
In-app purchases
RxMarbles
No in-app purchases
Siftmind
- Siftmind Premium Monthly$9.991 Month
- Siftmind Premium Annual$59.991 Year





