A small iOS development studio

We build software that
respects the data you put into it.

TwistedData Studios is a tiny, opinionated studio shipping native iPhone and iPad apps. Three are on the App Store, a fourth — a game — is in App Review, and a fifth is still on the bench. Each does its work on the device it runs on, without required accounts, without selling your data, and with every third-party SDK we depend on named openly in the privacy policy.

Dashboard Today 47 min sunlight 1240 IU vitamin D 207% of goal Last 7 days Deficiency Risk LOW 18 / 100
Dashboard RECORDING 12.4 mi Recognized your car · Ford SYNC Started 8:14 AM · $8.99 so far UNCLAIMED $187.40 Oldest trip is 24 days old Tracking is healthy Always + Precise location · Motion · Bluetooth THIS MONTH 318 mi Business $230.55 Reimbursable
Today 72 HPA BALANCE Load likely moderate today Today's recommendation Easy 30-min walk, then 5 minutes of slow breathing. Skip the hard session. HRV (SDNN) 58 ms ▲ trending up Deep sleep 1h 42m solid night
How we build

Three rules we don't break.

Every product we ship is held to the same three commitments. They shape what we can and can't build, and they're why our software feels different from what's around it.

On-device by default

What you enter and what we calculate stays on your phone wherever it can. Servers are an absolute last resort, and we tell you when one is touched.

No required accounts

Our apps work without you signing up for anything. Where we offer Sign in with Apple, it's optional and used only for a single, named feature — never as a gate.

Honest UI

Estimates are clearly labeled as estimates. Simulations are clearly labeled as simulations. We'd rather say "we're not sure" than fake precision.

Apps

What we ship.

Three live on the App Store. SolGlow and CalmTide are companions — connect both and they share data on-device to get smarter. Rustfall: Defense Protocol is in App Review, and Hedge Fund CEO is in development. Both are on the roadmap below.

Live · Free · Pro from $9.99
SolGlow
Health & Fitness · iPhone + Apple Watch

A vitamin D companion for iPhone. Estimates the vitamin D you produced from sunlight today using your Apple Watch's Time in Daylight, your skin type, your location, and what you ate — all on the device.

  • Reads Apple Health Time in Daylight; writes vitamin D back as dietary samples.
  • Burn-risk warnings tuned to your Fitzpatrick skin type and the day's UV.
  • Weekly Sun Plan, Annual Plan, 60-day history with location-aware attribution.
  • New in 2.0: Sun Today puts your vitamin D window and today's sun protection in one answer, plus free Sun Sensitivity, a Monthly Skin Check, cited Learn & Sources guides, and layouts made for iPhone Duo.
  • No account. No analytics. Just a single UV-forecast network call.
Live · Free · Pro from $4.99
CalmTide
Health & Fitness · iPhone + Apple Watch

A stress-load and HPA-axis tracker. Turns the HRV, sleep, and workout data your Apple Watch already collects into a daily HPA Balance Score and a weekly balance trend — estimates that say what they rest on, never a cortisol measurement.

  • Weekly HPA Balance Score from HRV, sleep, training load & breathwork.
  • A daily load estimate with one smart, personalised recommendation.
  • Your weekly HPA balance over 8 weeks, with life events pinned to it.
  • New in 2.0: a Breathe tab you can follow with your eyes closed, balance and readiness complications on your watch face, and every cited study re-checked — atop 1.8's practice library and live heart rate on the wrist.
  • Connects with SolGlow for morning-sun data. On-device, no account.
Live · Free · Pro $39.99/yr
TripSnap
Finance · iPhone

An automatic mileage tracker that knows the difference between your car and a bus. It recognises the car you're sitting in, records the drive in the background, and builds the expense report that actually gets you reimbursed.

  • Starts because CarPlay or your saved car stereo connected — not because you moved.
  • Tracking Health card names the permission that broke, the day it breaks.
  • Recording is free and never stops — no monthly drive limit, nothing deleted. Free opens your 10 most recent drives.
  • TripSnap Pro (1 month free): your whole log, the PDF report your manager accepts, gig shifts with $/hour after fuel, and deadline alerts.
  • No account, no TripSnap server, no employer dashboard — the only services it talks to are Apple's.
In review · Tower defense

Rustfall: Defense Protocol

The machines won the war. Build and fork twelve lines of emplacements around the last human city and hold it across 20 missions, 618 waves and six named bosses. Act I is free, one purchase unlocks the rest, and there are no ads. For iPhone and iPad.

See the screenshots
Rustfall gameplay: Vespera, Hive Mother, attacks at wave 20 on Cinderfield under an acid-rain alert.
5
apps built
0
data ever sold
100%
native Swift
∅
required accounts
What's next

The road ahead.

A short, honest snapshot of what we're working on. We update this page when releases ship — not before.

Five apps, shipping one at a time.

We ship one focused release at a time — each when it's ready, not when a sprint board says it should. This list is kept current as builds ship and reviews clear.

  • Live · v2.0 SolGlow 2.0 — vitamin D companion. Shipped Apr 2026, now on 2.0: Sun Today answers when your vitamin D window opens and what protection today's UV calls for, with free Sun Sensitivity, a Monthly Skin Check and cited Learn & Sources guides. See the update history →
  • Live · v2.0 CalmTide 2.0 — stress-load & HPA-axis tracker that connects with SolGlow. Now on 2.0: a Breathe tab you can follow with your eyes closed, balance and readiness complications on the watch face, a Trend in weekly HPA balance, and every cited study re-checked — after 1.8 added a practice library and live heart rate on the wrist. See the update history →
  • Live · v1.0 · Sep 2026 TripSnap 1.0 — automatic mileage tracker for people who get reimbursed for driving, on the App Store since 12 September. Car-aware capture that never stops recording, a tracking-health monitor, pay-period expense reports, and a second mode for gig drivers — with TripSnap Pro opening the whole log. Read the product page →
  • In review Rustfall: Defense Protocol 1.0 — a tower defense game for iPhone and iPad: the machines won the war, and you're holding the last city. Submitted to App Review. Act I is free, one purchase unlocks the full 20-mission campaign, and there are no ads. See the game →
  • In development Hedge Fund CEO 1.0 — stock-trading simulator. Still being built, and later than we first planned; we'd rather say so than keep quoting a date. Read what it does →
Press & resources

For writers and reviewers.

Short PDFs for each product with the headline numbers, the science (or the spec), and the privacy claims spelled out. Also where to point a link.