# Tau Lambda vs OneTopic

The clearest difference is update cadence: OneTopic at every 9 days against Tau Lambda's every 39 months. OneTopic also leads on iOS requirement (13.0 vs 16.1). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Tau Lambda ships an update every 39 months, OneTopic every 9 days. The most recent releases landed on September 10, 2026 and September 28, 2026 respectively.

## The numbers

| Metric | Tau Lambda | OneTopic |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.9 (31 ratings)](https://appshunter.io/ios/app/onetopic-the-daily-question/id6754181660/reviews)** |
| Number of ratings | — | **31** |
| Positive reviews | — | 95.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 39 months | **Every 9 days** |
| Monetization | — | Free |
| Size | 26 MB | 75 MB |
| Requires iOS | 16.1 | **13.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Ricardo Cumberbatch](https://appshunter.io/developer/1455104172) | [OneTopic LLC](https://appshunter.io/developer/1846952223) |

## What reviewers say

### Tau Lambda

[App page](https://appshunter.io/ios/app/tau-lambda/id1592825644)

**Features:** macOS Compatibility, Apple Wallet

**In-app purchases:** none


### OneTopic

[App page](https://appshunter.io/ios/app/onetopic-the-daily-question/id6754181660)

Engage in a daily global discussion centered around a single, thought-provoking question. Vote on the day's topic, read diverse perspectives, and participate in focused conversations without the distraction of endless feeds or algorithms.

**Highlights:** One daily global question, Real-time global voting, Focused discussion on a single topic, No algorithms or infinite feed, Submit questions for future debates, Daily ritual for collective thinking

**In-app purchases:** none


## Frequently asked questions

### Is Tau Lambda free?

Tau Lambda is free to download, with no in-app purchases.

### Is OneTopic free?

OneTopic is free to download, with no in-app purchases.

### Do Tau Lambda or OneTopic have ads?

Neither Tau Lambda nor OneTopic shows ads.

### Which is updated more often, Tau Lambda or OneTopic?

Tau Lambda ships an update every 39 months, and OneTopic every 9 days. Most recently, Tau Lambda was updated on September 10, 2026 and OneTopic on September 28, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*