Stack Testers Flow Friend vs Proton Authenticator & 2FA
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stack Testers Flow Friend
This mobile toolkit assists environmental engineers with on-site calculations for stack testing. Quickly determine velocity and volume flow by inputting stack size and gas conditions, eliminating the need for manual calculations or laptops. It also aids in calculating differential pressure cell mA output for data logging.
- Velocity and volume flow calculations
- Input stack size and gas conditions
- Differential pressure cell mA output calculation
- Preloaded Engineers Note Book content
- On-site calculation tool
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Stack Testers Flow Friend is part of a suite of apps developed by the Engineers of CES Environmental Instruments, one of the UKs leading environmental Test Houses and incorporates some of their on-site calculations in an easy to use app. When working on the stack and you need to quickly calculate a velocity or volume flow, the answer can be at your fingertips. By inputting the essential parameters of the stack size and gas conditions, the velocity and volume flow can be determined without the need to manually calculate the value or start up a laptop. The app is an essential tool for the professional Environmental engineer. The app is a useful aid to the C & I engineer calculating the Differential Pressure cell mA output used for data logging. The contents of the CES Environmental Instruments popular Engineers Note Book is preloaded within the app.
Proton Authenticator & 2FA
Securely manage your two-factor authentication codes with an open-source, end-to-end encrypted authenticator app. It offers seamless cross-device syncing, effortless import from other apps, and robust backup options, all protected by strict Swiss privacy laws. Take control of your digital security with a trusted and private solution.
- End-to-end encrypted iCloud sync
- Effortless import from other authenticators
- Secure backup and export
- Swiss privacy by design
- Open source and transparent
- Offline support
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Get the authenticator trusted by millions — from Proton Mail, the world's largest encrypted email provider. Proton Authenticator is open source, end-to-end encrypted, and protected by strict Swiss privacy laws. Protect all your new accounts and strengthen security on your existing ones. Proton Authenticator keeps your 2FA codes secure, accessible, and completely private — with full control over where your data is stored. KEY FEATURES Local-First Storage:Your 2FA codes are stored entirely on your device, giving you complete control over your data. Effortless Import: Migrate from Google Authenticator, Authy, or any other app in seconds. Secure Backup & Export: Retain full control of your data with easy backup and restore options. Swiss Privacy by Design: Built under Switzerland's strongest data protection regulations. Open Source & Transparent: Auditable code. No tracking. No ads. Take control of your digital security with encryption you can trust. Free to use: No Proton account required, ad-free. Offline support: On mobile and desktop apps No other 2FA app provides this combination of security and privacy. Trusted by millions. Built by Proton. Take control of your digital security today. Terms of service: https://proton.me/legal/terms Learn more: https://proton.me
Screenshots
Verdict
The clearest difference is review sentiment: Proton Authenticator & 2FA at 58% against Stack Testers Flow Friend's 0%. Proton Authenticator & 2FA also leads on update cadence (weekly vs every 8 months) and chart position (#132 vs unranked). Stack Testers Flow Friend's advantage is iOS requirement (13.0 vs 17.0). On price, ads, in-app purchases and monetization model 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. Neither carries in-app purchases, so what you see is what you pay.
Stack Testers Flow Friend ships an update every 8 months, Proton Authenticator & 2FA weekly. The most recent releases landed on October 22, 2026 and October 31, 2026 respectively.
| Parameter | Stack Testers Flow Friend | Proton Authenticator & 2FA |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.6 (572 ratings) — better |
| Positive reviews | 0.0% of reviews | 57.6% of reviews — better |
| Number of ratings | — | 572 — better |
| Update frequency | Every 8 months | Weekly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Best chart rank | — | #132 — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple Watch |
| Requires iOS | 13.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 32 MB | 120 MB |
| Age rating | 4+ | 4+ |
| Developer | Lewis Holmes | Proton AG |
Customer experience
Stack Testers Flow Friend
Proton Authenticator & 2FA
Bugs and requests
Stack Testers Flow Friend
Not enough reviews yet to summarise bugs or requests.
Proton Authenticator & 2FA
Reported bugs
4 issues- Sync/login loop on iPad
- 2FA input broken on non-iPhone devices
- Screen strobing on iPad
- Duplicate entries after import
Requested features
5 requests- PIN unlock for desktop
- Alphabetical sorting option
- Export function (not just Proton-specific backup)
- Native macOS app
- Option to hide item icons
In-app purchases
Stack Testers Flow Friend
No in-app purchases
Proton Authenticator & 2FA
No in-app purchases
Questions
Is Stack Testers Flow Friend free?
Is Proton Authenticator & 2FA free?
Do Stack Testers Flow Friend or Proton Authenticator & 2FA have ads?
Which is updated more often, Stack Testers Flow Friend or Proton Authenticator & 2FA?
Other comparisons
