Circa vs muttlog
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Circa
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Circa is an iPhone app that logs your supplements, caffeine, and nicotine in two taps and pairs them with your Google Fitbit Air data to turn the two into trend insights, audited correlations, and a live forecast for tonight's sleep. Everything is computed on your iPhone. There is no Circa account and no Circa server. Circa is free and shows advertising, which is loaded over the network. PRECISE INPUTS Log anything in two taps: exact dose, exact unit, exact time. Your stack is a shortcut, never a constraint — type any amount, switch units freely (mg, g, µg, IU, pouch, ml, drops). One-tap logging from the Lock Screen widget, or just tell Siri "Log an espresso in Circa." STIMULANT PHARMACOKINETICS Live caffeine and nicotine decay curves against your bedtime, with the 50 mg caffeine threshold drawn where it matters. See what this afternoon's espresso still costs you at 23:00. AUDITED INSIGHTS Every effect ships with its receipts: n, 95% confidence interval, p-value, correlation — and the actual nights behind it as a scatter plot. Insights that fail their interval for 14 days are retired automatically. Honest null results included. TONIGHT, FORECAST A transparent driver model predicts tonight's sleep score and deep-sleep minutes from what you actually did today. Every driver shows its signed contribution. It recomputes on every log — watch the number move. A 104-SUPPLEMENT LIBRARY Goal-ranked, evidence-graded, interaction-flagged. Pick your goals and the library re-ranks itself around you. YOUR DATA STAYS YOURS Health data is read from the Google Health API and processed entirely on-device. Disconnecting revokes access and erases everything. Export anytime as CSV and JSON. Explore the full app in demo mode before connecting anything. Circa is a personal tracking tool, not a medical device. It does not diagnose, treat, or prevent any condition. Requires a Google Fitbit Air and a Google account for live data; manual logging and demo mode work without one.
muttlog
This app helps you log your dog's daily exercise, social interactions, and training progress. It offers visual charts, teaching guidance for core commands, and motivational streaks. Unlock advanced features and multiple dog profiles with a subscription.
- Exercise, Social, and Behavior progress scores
- Visual progress chart
- Core command tracking
- Teaching guidance for commands
- Streaks and badges
- Multiple dog profiles (Pro)
- Cloud backup (Pro)
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Muttlog helps you track your dog’s daily exercise, social time, and training progress in one calm, simple place. Features: - Progress scores for Exercise, Social, and Behavior - A visual progress chart for quick weekly check-ins - Core command tracking for Sit, Down, Wait, Stay, Come, Off, and more - Teaching guidance for each command - Streaks and badges to encourage consistency - Multiple dog profiles with Muttlog Pro - Advanced command tracking with Muttlog Pro - Optional cloud backup with Muttlog Pro Muttlog is designed to be gentle, practical, and encouraging. No guilt, no complicated training system, just a steady way to build better habits with your dog. Muttlog Pro is available as an auto-renewable subscription. Payment is charged to your Apple ID at confirmation of purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. You can manage or cancel your subscription in your App Store account settings. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://frevanto.com/privacy.html Support: https://frevanto.com/contact.html
Screenshots
Verdict
The clearest difference is in-app purchases: Circa at none against muttlog's 2. muttlog's advantage is ads (none vs shown) and update cadence (every 6 days vs every 5 weeks). On price and device support 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. muttlog sells 2 in-app purchases, starting at $1.99 per month. Circa asks for nothing beyond the download.
Circa ships an update every 5 weeks, muttlog every 6 days. The most recent releases landed on October 12, 2026 and October 16, 2026 respectively.
| Parameter | Circa | muttlog |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (3 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 3 — better |
| Update frequency | Every 5 weeks | Every 6 days — better |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Monetization | — | Freemium |
| Devices | iPhone | iPhone, iPod — better |
| Requires iOS | 17.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 7 MB | 48 MB |
| Age rating | 12+ | 4+ |
| Developer | Levin David Schwab | Peter Williams |
In-app purchases
Circa
No in-app purchases
muttlog
- Monthly Pro Subscription$1.991 Month
- Pro$9.991 Year









