Keld Wellspring
Your body's sunstone
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Keld connects the dots between your biology and your world, smart watch, food, glucose, sleep, weather, everything - you can finally see why your body does what it does.
Keld is a personal weather service for your body.
It quietly correlates the signals from your Apple Watch and iPhone — heart rate variability, sleep, breathing, steps, blood oxygen, and dozens more — with the world you actually live in: the weather above you, the air you breathe, the pollen drifting through, the sound around you, and the places you spend time.
When a real pattern emerges, Keld names it. Not a number. Not a chart. A two-word name, a unique sigil, and a quiet evidence card explaining what makes it yours.
FOUR KINDS OF PATTERNS
• Body — patterns inside your biology
• Weather — patterns in the air, light, and sky
• Geometric — patterns at YOUR specific places
• Hybrid — patterns that weave biology, weather, and place together
A LIVING LIBRARY
Every Element gets a unique sigil, a haiku-style name, and a mathematically honest confidence tier — Proven, Forming, or earlier. Tap any Element to see exactly what supports it.
WHAT'S COMING NEXT
A dedicated Forecasts tab shows your next 24 hours of biometric modes, the 10-day weather, and the planets above your head right now.
ATMOSPHERE PANELS
Smooth, real-time charts for temperature, pressure, humidity, wind, air quality, pollen, audio exposure, and place density.
PRIVACY BY ARCHITECTURE
Your raw Apple Health data never leaves your device. Your precise location is snapped to a 500-meter grid on-device before any analysis. No account. No email. No password. Anonymous device identifier only.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & Reviews
v1.8.2 — your body's sunstone, sharper
The biggest Keld release since launch. Every page touched, four new data sources added, and a new way to see how the world moves your body.
NEW: PULSE HOME PAGE
Four colored dials show your discovered patterns by category: Body, Weather, Geometric, Hybrid. A new Tip Jar suggests what to explore next.
NEW: GEOMETRIC ELEMENTS
Keld now learns the places you spend time and finds patterns that only appear there. Discover that your heart rate variability runs high at one specific coffee shop, or that you sleep better after evenings at home versus elsewhere.
NEW: HYBRID ELEMENTS
Three-, four-, and five-way patterns that combine your biology, the weather, and your places into a single named signature. Real physiology isn't pairwise — neither are these.
NEW: FORECASTS TAB
A dedicated section for what's coming next. Bio Radar predicts your next 24 hours of biometric modes. Weather gives you 10 days ahead. Cosmos shows where the sun, moon, and the five naked-eye planets are in your sky right now.
NEW: AIR QUALITY & POLLEN PANEL
Per-metric air quality and pollen detail with thresholds and bands matching EPA and Universal Pollen Index scales. Tap any pollutant for the full readout.
NEW: AUDIO EXPOSURE PANEL
Separate ambient and headphone NIOSH dose tracking, matching how Apple Health splits the two.
NEW: PLACE DENSITY PANEL
Population and points-of-interest density for every cell you visit. Suburban, urban, dense, or metropolitan — categorized at a glance.
NEW: ATMOSPHERE OVER TIME
A multi-metric weather chart with smooth curves and threshold-based coloring. Switch between temperature, pressure, humidity, wind, AQI, pollen, and precipitation on a single timeline.
NEW: ELEMENT NAMES
Every Element now gets an AI-coined two-word name like "Resonant Wake" or "Bright Burn" — more memorable, more yours.
NEW: SAGA "WHERE BODY MEETS WORLD"
When the day's weather and your biology aligned in a meaningful way, the shareable Saga video opens a new chapter showing that intersection.
LIBRARY → LEDGER
Restructured into 12 collapsible sublists — 3 confidence tiers across all 4 Element categories. Tap any to drill in.
PERFORMANCE
Cold-reopen freezes after long backgrounding — eliminated. Chart stutter at 7-day and 30-day windows — eliminated. The Geometrics map pinch-zoom crash — fixed.
PRIVACY UNCHANGED
Your raw biometric data still never leaves the device. Location is still snapped to a 500-meter grid before any analysis. Anonymous device-only identifier — no account required.
Update via the App Store. Your sunstone, sharper.
The developer, Brian Gansereit, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Health & Fitness
- Location
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Brian Gansereit
- Size
- 118.4 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Location
- This app may use your location even when it isn’t open, which can decrease device battery life.
- Languages
- English
- Age Rating
16+
- 16+
- Contains
Unrestricted Web Access
User-Generated Content
Health or Wellness Topics
- In-App Purchases
Yes
- Keld+ $9.99
- Keld+ $99.99
- Copyright
- © 2026 BioSignal AI

