S2 vs Byrner
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
S2
This app helps you track and visualize your gym workout progress, encouraging progressive overload for weight loss or muscle gain. It offers a fast, intuitive interface with over 1000 exercises and a unique muscle fatigue heat map. No account is needed, and it integrates with HealthKit.
- Track and visualize workout progress
- Muscle fatigue heat map
- Create unlimited workout routines
- Encourages progressive overload
- 1000+ exercises
- Workout history review
- HealthKit integration
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S2 (Superior Self) is your ultimate workout companion, allowing you to track and visualize your workout progress. Whether you want to lose weight or gain muscle mass, S2 is an excellent tool to help you with progressive overload and beat the yesterday you. - Premium, beautiful workout app - No account registration is required - Fast and intuitive. No load times - View your muscle fatigue on a body heat map - Create unlimited workout routines - Encourages progressive overload - 1000+ exercises - Improved insights over time How does it work? Start by creating your workout routines in S2. Your first workout for any given routine will act as a baseline for the next workout, encouraging you to do more work by moving more mass. The technical term for this is called progressive overload, and it's the core principle behind any successful strength training. Between workouts (or during an ongoing workout) you can review your past performance by easily accessing your workout history. S2 integrates with HealthKit to register your workouts. Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Byrner
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Byrner is the lowest-friction way to track calories: type in plain English what you ate or which workout you did — a language model does the rest. No database to search, no portions to weigh, no 20 fields to fill in. "Bowl with rice and chicken" is enough. Byrner estimates the calories, shows its assumptions ("toast: assumed 2 slices") and gives you your running daily balance right away. Runs on your iPhone — no key, no cost On iPhones with Apple Intelligence (iPhone 15 Pro or newer, iOS 26+), Byrner estimates calories entirely on-device. No API key, no cloud, no running costs — nothing leaves your iPhone. It's set up the moment you launch; just start logging. Reply without opening the app Four times a day a notification asks what you ate. You reply straight from the notification — one tap, done. Snacks, meals logged later and workouts go in anytime via the plus button. Your budget, no math Byrner works out your daily budget from your age, height, weight, sex, everyday activity and goal (lose, maintain or build) — set it once and you're done. You can still adjust the number by hand anytime. Not just calories — macros too For every meal Byrner also estimates protein, fat and sugar in grams. It sets a protein target for your goal that you track right in the daily overview. Or connect your own provider No Apple Intelligence on your device, or you want a specific model? Byrner is provider-agnostic — it has no backend of its own and no hidden servers. Connect the provider you trust: • Anthropic (Claude) • OpenAI • Groq, OpenRouter, Mistral, DeepSeek and other OpenAI-compatible services • Local models via Ollama or LM Studio Model and endpoint are freely editable. Use new models the moment they ship, with no app update. No subscription. Really. Byrner doesn't sell you a monthly plan. On-device costs nothing. Connect a cloud provider and you only pay for its usage — cents per month with the usual models. Local-first & private Every entry lives in SwiftData on your iPhone. No account, no forced sync, no tracking. On-device, nothing leaves your iPhone at all; with a cloud provider, only your input text goes to the service you picked — and you decide which one. Honest, not falsely precise Calorie estimates are directional, not exact to the calorie. Byrner shows its uncertainty instead of hiding it: every entry has a confidence indicator and a portion note — and can be corrected or re-estimated with a tap. Entry details also show an estimate range (e.g. ± 20%). For trends, consistency matters more than decimal places. What Byrner does • Free-text input for food and exercise • On-device with Apple Intelligence — no key, no cost (on supported devices) • Inline reply straight from the notification • Running daily balance (consumed minus burned) • History of past days • Daily budget — calculated from your body data & goal, or set manually • Macros per meal: protein, fat, sugar — plus a protein target • Estimate range per entry (e.g. ± 20%) • Configurable reminder times • Correct entries and have them re-estimated Note: On iPhones with Apple Intelligence, Byrner works with no setup at all. On older devices you connect your own LLM provider (your own API key) or a locally running model — setup takes a minute and is walked through step by step on first launch.
Screenshots
Verdict
The clearest difference is in-app purchases: Byrner at none against S2's 2. On price, ads, device support and iOS requirement 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. S2 sells 2 in-app purchases, starting at $22.99 per year. Byrner asks for nothing beyond the download.
| Parameter | S2 | Byrner |
|---|---|---|
| Price | Free | Free |
| Rating | 4.1 (129 ratings) — better | — |
| Positive reviews | 41.3% of reviews | — |
| Number of ratings | 129 — better | — |
| Update frequency | Fortnightly | — |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone | iPhone |
| Requires iOS | 16.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 9 MB | 1 MB |
| Age rating | 12+ | 4+ |
| Developer | Formbound AB | Andreas Gaschka |
In-app purchases
S2
- S2 Yearly$22.991 Year
- Strongly Pro$4.99
Byrner
No in-app purchases









