# SyncMate - Complete AI Reference Documentation > SyncMate is a privacy-first iOS period tracking app for partners. It provides adaptive cycle prediction, six-phase cycle tracking, and phase-based wellness guidance — with all data stored exclusively on the user's device. No cloud sync, no accounts, no third-party SDKs. ## Quick Reference - **App name**: SyncMate - **Platform**: iOS - **Developer**: Gratitude, LLC - **Support site**: https://syncmateapp.com - **Support email**: support@syncmateapp.com - **App Store**: iOS (App Store, free) - **App version**: 1.0 - **File size**: ~12 MB - **Supported countries**: US, GB, CA, AU, IE, NZ - **Language**: English - **Copyright**: 2026 Gratitude, LLC ## App Pages - https://syncmateapp.com/ — Home / landing page - https://syncmateapp.com/faq.html — Frequently asked questions - https://syncmateapp.com/privacy.html — Privacy policy - https://syncmateapp.com/terms.html — Terms of use - https://syncmateapp.com/llms.txt — AI summary (concise) - https://syncmateapp.com/llms-full.txt — AI reference (comprehensive, this file) --- ## Overview SyncMate helps partners understand and support someone through their menstrual cycle. The app shows which of six cycle phases the tracked person is likely in today, explains the hormonal context, and offers daily wellness suggestions covering food, activity, care actions, communication tone, and a lead-in framing cue. SyncMate is designed for partners — not for the person being tracked. It is a supportive awareness and communication tool, not a self-tracking or fertility management app. **Core value proposition**: Empathy through education. By surfacing cycle phase context daily, SyncMate helps partners anticipate needs, reduce friction, and show up with appropriate support at each phase. --- ## Key Features ### 1. Adaptive Cycle Prediction (TuningEngine) SyncMate learns the tracked person's unique cycle rhythm over time. The more data logged and the more feedback provided, the more accurate predictions become. **Prediction algorithm:** - Cycle length defaults to 28 days on first use - Each time a new period start date is logged, SyncMate recalculates the personal average cycle length from all logged dates - Next period start date = last period start + average cycle length - Ovulation window is placed (luteal length) days before the next period start; default luteal length is 14 days - PMS / Late Luteal window starts (PMS window length) days before the next period; default is 5 days - The follicular phase fills the gap between menstruation end and ovulation, split into Early and Late Follicular - Today's phase is determined by where the current date falls within the calculated framework **TuningEngine — adaptive phase boundary adjustment:** The TuningEngine watches daily thumbs-up / thumbs-down feedback and automatically fine-tunes two parameters: - **Luteal delta (Δ)**: Shifts the estimated ovulation window earlier or later by up to ±2 days - **PMS delta (Δ)**: Shifts the start of the PMS / Late Luteal window earlier or later by up to ±3 days How the algorithm works: 1. Each day the user taps thumbs-up or thumbs-down to rate whether today's phase description felt accurate 2. The TuningEngine examines up to 60 recent feedback entries 3. If 60% or more of feedback in the 3 days before a phase boundary is negative, the boundary shifts earlier (the phase was starting too late in predictions) 4. If 60% or more of feedback in the first 2 days inside a phase boundary is negative, the boundary shifts later (the phase was starting too early) 5. Adjustments require at least 3 qualifying feedback entries before triggering — preventing single-day noise from skewing predictions 6. The TuningEngine only modifies delta offsets; it never changes base settings 7. Current Luteal Δ and PMS Δ values are visible and resettable in Settings → Tuned Adjustments (Auto) **Accuracy expectations:** - 1 period logged: uses 28-day default; predictions are approximate - 2+ periods logged: personal average cycle length applied; next-period accuracy improves significantly - 3–4 periods + consistent feedback: most users find predictions land within 1–2 days of actual phase transitions - Treat all dates as estimates within a ±2–3 day window; natural cycle variation from stress, illness, travel affects timing ### 2. Six-Phase Cycle Tracking SyncMate divides the menstrual cycle into six distinct phases: **Phase 1: Menstruation** - Timing: Day 1 of bleeding through end of menstruation (default 5 days, adjustable 2–8 days) - Hormonal context: Estrogen and progesterone at their lowest. Prostaglandins rise, which causes uterine contractions and can produce cramps. The uterine lining sheds. - Mood and energy: Energy and mood tend to dip. Fatigue and inward focus are common. - Support approach: Warmth, comfort, and rest. Physical care — heat packs, warm drinks. Low-demand conversation. - Nutrient focus: Iron and vitamin C to offset blood loss; omega-3 and magnesium to reduce inflammation and cramping - Example suggestions: Warm beet and carrot soup for iron and vitamin C; heat a wheat bag; check in with "Would rest or cuddles feel good?" **Phase 2: Early Follicular** - Timing: Immediately after menstruation ends; estrogen begins climbing from its lowest point - Hormonal context: FSH (follicle-stimulating hormone) rises, recruiting follicles for maturation. Estrogen begins climbing, which supports mood and motivation. Progesterone remains low. - Mood and energy: Energy starts rebuilding. Mood brightens as estrogen rises. Increasing openness to activity. - Support approach: Gentle encouragement; low-key activities that match recovering energy - Nutrient focus: Lean proteins and fiber for steady energy as estrogen climbs; foods that support hormone production - Example suggestions: Quinoa salad with avocado for stable energy; short nature walk or coffee in the sun; leave an appreciation note **Phase 3: Late Follicular** - Timing: Approaching ovulation; estrogen peaks near its monthly high - Hormonal context: Estrogen reaches near-peak levels. LH (luteinising hormone) primes for its surge. Testosterone also rises slightly, supporting confidence and libido. - Mood and energy: Confidence, creativity, and sociability are often at their highest. Social engagement feels natural and energising. - Support approach: Social plans, creative activities, and conversations that engage her ideas and plans - Nutrient focus: Omega-3 fatty acids to support hormonal activity; foods that sustain the pre-ovulation energy peak - Example suggestions: Sushi or a poke bowl (omega-3); pottery or painting class, or a casual dinner with friends; ask about her ideas and plans **Phase 4: Ovulation Window** - Timing: A brief peak window spanning roughly 3 days; LH surge triggers ovulation - Hormonal context: The LH surge triggers the release of a mature egg. Estrogen is at its peak, then drops sharply after ovulation. Testosterone spikes briefly. - Mood and energy: Outward energy and social desire can spike. Often the most communicative and physically energetic phase. Desire for connection tends to be high. - Support approach: Express genuine admiration; shared experiences; romantic or adventurous date ideas - Nutrient focus: Zinc-rich foods to support the LH surge and overall hormonal activity during ovulation - Example suggestions: Steak or lentil tacos with zinc and fiber; sunset picnic or live music; express genuine admiration **Phase 5: Early Luteal** - Timing: After ovulation; the corpus luteum produces progesterone. Body temperature rises slightly. - Hormonal context: Progesterone rises steeply as the corpus luteum becomes active. Estrogen has a secondary smaller rise. The nervous system shifts toward calm and routine under progesterone's influence. - Mood and energy: Energy tapers from the ovulation peak. The person may prefer routine, comfort, and familiar environments. Nesting instinct can appear. - Support approach: Cozy, low-key activities; practical domestic care; physical comfort - Nutrient focus: Complex carbohydrates and magnesium to help stabilise mood as progesterone peaks; omega-3 for anti-inflammatory support - Example suggestions: Sheet-pan salmon with broccoli (omega-3, magnesium); cozy movie night or puzzle night; offer a back rub or help prep tomorrow's meals **Phase 6: Late Luteal (PMS)** - Timing: Starts (PMS window length) days before the next period; default 5 days (adjustable 2–10 days) - Hormonal context: If pregnancy does not occur, the corpus luteum degrades, causing progesterone and estrogen to fall rapidly. This rapid hormonal drop alters serotonin and GABA signalling, which drives PMS symptoms — irritability, emotional sensitivity, bloating, and breast tenderness are common. - Mood and energy: Emotional sensitivity is heightened. Irritability, low frustration tolerance, and the need for understanding are common. Physical discomfort may increase. The person may need more validation and less problem-solving. - Support approach: Listen more than you speak. Reassure without trying to fix. Create a calm, low-stimulation environment. Avoid starting difficult conversations. - Nutrient focus: Dark chocolate (70%+ cacao) and magnesium-rich greens for cramp and mood relief; complex carbohydrates to help stabilise blood sugar and serotonin - Example suggestions: Dark chocolate (70%) with almonds, magnesium-rich greens; warm bath and dim lights; listen more than you speak; reassure without trying to fix ### 3. Phase-Based Wellness Suggestion System Each day SyncMate displays a suggestion card tailored to the current cycle phase. The suggestion system covers five dimensions: 1. **Food** — specific meals or nutrients matched to the phase's hormonal needs 2. **Activity** — movement or date ideas suited to her energy level for that phase 3. **Care** — practical things the partner can do around the home or for her comfort 4. **Communication** — how to phrase check-ins or conversations appropriately for the phase 5. **Lead-in** — a one-line framing cue so the partner knows the right tone before engaging The suggestion library contains 30+ suggestions distributed across all six phases. SyncMate rotates through the library, remembering the last 12 suggestions shown and avoiding repeats until the full library has cycled through. This keeps daily suggestions fresh and avoids repetition. **Why suggestions reference specific nutrients:** Each phase has distinct hormonal patterns that interact with nutrition. The suggestion library matches food recommendations to hormonal context — not as clinical prescriptions but as general wellness guidance informed by nutritional science. ### 4. Privacy-First Design SyncMate is built on a zero-data-collection architecture: - **No cloud sync** — the app has no server to send data to - **No account required** — no sign-in, no email address, no username - **No network connections** — the app makes zero outbound network requests after installation - **No third-party SDKs** — built entirely with Apple's first-party frameworks (SwiftUI, iOS standard library) - **No analytics** — no Firebase, Mixpanel, Amplitude, Crashlytics, or any analytics product - **No advertising** — no AdMob, Meta Audience Network, or ad SDK of any kind - **No crash reporting** — no Sentry, Bugsnag, or remote error logging - **No attribution or deep-link SDK** — no Adjust, AppsFlyer, or Branch - **Fully offline** — every feature works in Airplane Mode; no server is ever contacted ### 5. Local Data Storage (UserDefaults) SyncMate stores all user data using **iOS UserDefaults**, the standard Apple-provided on-device key-value storage: **What is stored:** - Period start dates logged by the user - Cycle predictions (computed on-device) - Daily feedback entries (thumbs-up / thumbs-down per day) - Cycle settings: menstruation length, luteal length, PMS window - TuningEngine delta values (Luteal Δ, PMS Δ) - Recent suggestion history (last 12 shown, to avoid repeats) - Notification preferences (scheduled time) **Storage characteristics:** - Stored in the app's private sandboxed container on the device file system - No other app can read SyncMate's UserDefaults - Not synced to iCloud (SyncMate does not opt in to iCloud key-value or iCloud Drive sync) - Not Core Data, not CloudKit, not SQLite — plain key-value UserDefaults only - Deleted automatically and permanently when the app is uninstalled - May be included in standard iOS device backups (iCloud Backup or local Finder/iTunes backup) if the user has backup enabled — but this is controlled entirely by the user via iOS Settings **What is NOT used:** - No HealthKit / Apple Health integration - No iCloud sync - No CloudKit - No Core Data with remote sync - No SQLite database files - No shared app group containers ### 6. Daily Local Notifications SyncMate can send a single daily reminder with the current phase insight: - Notifications are scheduled using iOS `UNCalendarNotificationTrigger` with a daily repeating time - Everything is local — no APNs (Apple Push Notification service) remote delivery, no server, no network call - Notification content is generated on-device at the time the notification fires - Notification structure: Title = "Today's Cycle Insight"; Subtitle = day label (e.g., "Day 14 — Ovulation Window"); Body = phase message + today's wellness suggestion **Setup:** Settings → Notifications → set Hour and Minute → tap "Reschedule Daily Notification." iOS will prompt for notification permission the first time; can also be managed via iOS Settings → Notifications → SyncMate. --- ## Technical Architecture ### Stack - **Language**: Swift - **UI framework**: SwiftUI - **Storage**: iOS UserDefaults (local key-value, sandboxed) - **Notifications**: UNCalendarNotificationTrigger (local, not remote APNs) - **Dependencies**: None (zero third-party libraries or SDKs) - **Build target**: iOS (current and recent versions) - **App size**: ~12 MB ### Architecture Principles **Privacy by design — not by configuration:** The absence of network capability is architectural. There is no network stack to configure, no API keys to rotate, no server infrastructure to secure. Data cannot leak because the data pathway to any external system does not exist. **No server-side processing:** All computations — cycle phase determination, TuningEngine adjustments, suggestion selection, notification scheduling — run entirely on the user's device. There is no server that receives data, processes it, and returns results. **Single-device model:** SyncMate is a single-device, local-only app by design. Cross-device sync is not supported. Data from one iPhone cannot be transferred to another except via iOS device backup/restore. **Consent-first onboarding:** The onboarding flow requires the user to explicitly confirm that their partner is aware the app is being used. SyncMate is designed to be a transparent, communicative tool — not a covert tracker. --- ## App Screens **Home screen (Today view):** - Shows today's cycle day number and phase name - Displays a daily insight card with the suggestion for today (food, activity, care, communication, lead-in) - Metrics row: average cycle length, next predicted period date - Thumbs-up / thumbs-down feedback bar - "Log New Period Start" button - Settings gear icon (top-right) **Timeline screen:** - Visual wheel / timeline showing all six cycle phases - Predicted next period start date marked - Current position in cycle highlighted **Phase detail screen:** - Hormonal context for the current phase - Mood notes and typical emotional patterns - Food and activity suggestions for the phase **Calendar view:** - Monthly calendar with cycle phases marked - Overview of phase transitions across the month **Settings screen:** - Cycle Settings (Base): Menstruation length (2–8 days, default 5), Luteal length (8–18 days, default 14), PMS window (2–10 days, default 5) - Tuned Adjustments (Auto): View current Luteal Δ and PMS Δ; Reset Tuning button - Notifications: Hour and Minute steppers; "Reschedule Daily Notification" button - Data: "Reset All Data" button (red; irreversible; clears all period history, feedback, settings, and tuning) --- ## Frequently Asked Questions — Key Highlights ### Getting Started **Q: How do I set up SyncMate for the first time?** On first launch, the onboarding screen asks for: (1) the last period start date via a calendar picker; (2) a consent checkbox confirming the partner is aware the app is being used. After tapping "Get Started," SyncMate calculates the current cycle phase immediately. **Q: What does SyncMate actually do?** SyncMate shows which of six cycle phases the tracked person is likely in today, explains hormonal context, provides a daily wellness suggestion (food, activity, care, communication tone), and predicts the next period start date. It learns from daily feedback to improve accuracy over time. **Q: Is SyncMate medical advice?** No. SyncMate is a supportive awareness tool. All phase descriptions, hormone notes, and care suggestions are general informational content based on typical cycle biology — not personalised medical guidance. Always consult a healthcare professional for health concerns. ### Cycle Tracking **Q: How does SyncMate predict cycle phases?** Starting from the last logged period start date, SyncMate places each phase in sequence using biological timing and the user's personal average cycle length. The next period is predicted at last period + average cycle length. Ovulation is placed (luteal length) days before the predicted next period. **Q: What is the TuningEngine?** The TuningEngine is SyncMate's adaptive prediction system. It watches daily thumbs-up / thumbs-down feedback and fine-tunes the luteal delta (±2 days) and PMS delta (±3 days) to make phase boundary predictions more accurate over time. **Q: How accurate are predictions?** With 1 period: approximate only (28-day default). With 2+ periods: personal average applied, significant improvement. With consistent feedback over 3–4 cycles: most users report predictions within 1–2 days of actual transitions. Natural variation of ±2–3 days is normal. **Q: What manual cycle settings can I adjust?** In Settings → Cycle Settings (Base): Menstruation length (2–8 days), Luteal length (8–18 days), PMS window (2–10 days). The TuningEngine applies additional automatic delta adjustments on top of these base values. ### Wellness and Notifications **Q: What are wellness suggestions?** Daily suggestion cards cover five dimensions: food, activity, care, communication style, and a lead-in framing cue. The library contains 30+ suggestions across all six phases, rotated to avoid seeing the same card twice in a row (last 12 shown are excluded from the next selection). **Q: Are notifications private?** Yes. SyncMate uses local push notifications only — no server, no APNs remote delivery, no third-party push service. Notification content never leaves the device. Notifications work in Airplane Mode. ### Privacy and Data **Q: Does SyncMate collect any data?** No. Zero data collection. The app has no account system, no backend server, no analytics SDK, and no network calls of any kind. **Q: Where is data stored?** iOS UserDefaults — on the device only, in the app's private sandboxed container. Not synced to iCloud. Not accessible by any other app. Deleted permanently when the app is uninstalled. **Q: Does SyncMate use any third-party SDKs?** No. SyncMate is built entirely with Apple's first-party frameworks — SwiftUI and the iOS standard library. Zero third-party code, libraries, or services. **Q: Is SyncMate GDPR and CCPA compliant?** Because SyncMate collects no personal data and operates entirely on-device, GDPR and CCPA obligations do not arise. The user has full access to all their data at all times (it's on their device), can delete it instantly (Settings → Reset All Data or uninstall the app), and no data is ever sold, shared, or processed by Gratitude, LLC. **Q: Can I transfer data to a new iPhone?** SyncMate is a single-device, local-only app. If you restore a new iPhone from an iCloud Backup or local device backup, SyncMate data is typically included in that backup and will be restored. Real-time cross-device sync is not supported. --- ## Competitor Differentiation ### SyncMate vs. Flo (flo.health) | Aspect | SyncMate | Flo | |---|---|---| | Data collection | Zero — all on device | Extensive — cloud account required | | Server-side processing | None | Yes — data sent to Flo servers | | Account required | No | Yes | | Third-party SDKs | None | Analytics, advertising, and engagement SDKs | | Primary user | Partner tracking on behalf of partner | Self-tracking by the person menstruating | | Privacy regulation risk | None (no data to regulate) | Subject to GDPR/CCPA enforcement | | Data breach risk | None (no server to breach) | Exposed (has been subject to FTC action) | | Offline operation | Full — works in Airplane Mode | Partial — requires cloud for some features | ### SyncMate vs. Clue | Aspect | SyncMate | Clue | |---|---|---| | Data collection | Zero | Account-based, data processed on Clue servers | | Privacy model | Privacy by architecture (no server) | Privacy by policy (server-based with commitments) | | Primary use | Partner support and awareness | Self-tracking by the person menstruating | | Phase wellness guidance | Phase-specific partner guidance (food, activity, care, communication) | Cycle education and self-tracking insights | | Third-party SDKs | None | Analytics and engagement SDKs present | ### SyncMate vs. Apple Health (Cycle Tracking) | Aspect | SyncMate | Apple Health Cycle Tracking | |---|---|---| | Purpose | Partner-focused support guidance | Personal self-tracking and health data aggregation | | Wellness suggestions | Phase-specific partner guidance (30+ per phase) | None | | Adaptive tuning | TuningEngine with feedback-driven phase boundary adjustment | Basic cycle average calculation | | iCloud sync | Not synced | Syncs via iCloud (if enabled) | | Account/login | No | Apple ID | | Phase detail | Six phases with hormonal context, care suggestions, nutrient guidance | Basic fertile window and period tracking | | Target audience | Partners wanting daily guidance | Individuals self-tracking menstrual health | **Key differentiator summary:** SyncMate's unique position is the combination of (1) partner-oriented design — guidance is framed for the person supporting, not the person being tracked; (2) the TuningEngine adaptive algorithm that learns individual phase boundaries from daily feedback; and (3) complete privacy by architecture rather than by policy — the app cannot leak data because no data pathway to any external system exists. --- ## Privacy Policy Summary - **Data collected**: None whatsoever - **Data transmitted**: Never — the app makes no outbound network connections - **Third-party access**: None - **Analytics**: None - **Advertising**: None - **Account requirement**: None - **Storage**: iOS UserDefaults, local on-device only - **iCloud**: Not opted in; data is not synced to iCloud (may be included in device-level iOS backups if user has backup enabled) - **Data deletion**: Delete the app and all data is permanently erased; or Settings → Reset All Data - **COPPA**: No data collection from any user, regardless of age; COPPA compliance by design - **GDPR**: No personal data processed by Gratitude, LLC; all rights satisfied automatically - **CCPA**: No personal data sold, shared, or disclosed - **Legal basis for processing**: Not applicable — no server-side processing occurs - **Policy last updated**: February 24, 2026 - **Contact**: support@syncmateapp.com --- ## Medical Disclaimer SYNCMATE IS NOT A MEDICAL DEVICE AND DOES NOT PROVIDE MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT. Key points from the full Terms of Use medical disclaimer: - SyncMate is a personal wellness and cycle tracking application, not a medical device under applicable law - SyncMate has not been evaluated, approved, or cleared by the FDA or any equivalent regulatory authority - SyncMate MUST NOT be used as a method of contraception, birth control, or pregnancy prevention - All cycle predictions, fertile window estimates, and ovulation date calculations are statistical estimates only; they are not clinically validated - Nothing in the app constitutes medical advice or a substitute for consultation with a qualified healthcare provider (physician, OB-GYN, or other licensed professional) - Never disregard, dismiss, or delay seeking professional medical advice because of something seen in the app - For medical emergencies, call 911 or local emergency services; do not use this app to evaluate or manage a medical emergency --- ## Support **Contact**: support@syncmateapp.com **Response time**: Within 5 business days **Support site**: https://syncmateapp.com **FAQ**: https://syncmateapp.com/faq.html When reporting a bug, include: iOS version (Settings → General → About → iOS Version) and a description of what happened. --- ## About Gratitude, LLC SyncMate is developed and published by Gratitude, LLC. The company operates the support site at syncmateapp.com. All intellectual property related to SyncMate, including the TuningEngine algorithm and suggestion library, is owned by Gratitude, LLC. Governing law: State of California, United States.