Building Neptune: The Web Coach, 72 Hours In
Neptune
March 31, 2026
The coach, in the browser
Three days earlier, Neptune lived on iPhone and Apple Watch. Today it also lives at neptune.coach. Same coach. Any device.
The point was not a marketing site. The point was a partner you can talk to before you own the phone.
Here's what shipped.
Day 1 — foundation
Could a surfer use Neptune without an iPhone in their pocket?
By night:
- Auth — email, Google, Apple Sign-In, same users as iOS
- The coach on the web — the same coaching engine, in the browser
- 537 surf spot pages — live conditions, local knowledge, a path into coaching
Each spot page is a door. Someone searching "Rincon surf conditions" lands on live data and a coach, not a dead forecast.
Day 2 — a real product
Day two made the web feel like the app, not a landing page with a chat widget.
Working on building in public? Partner with Neptune on iPhone and Apple Watch.
Get on iOS- Dashboard — live conditions for the spots you actually surf
- Favorites — synced with mobile
- Session logging — manual on the web; the Watch still tracks in the water
- Onboarding — level, home break, goals
- Settings and profile
The split is simple. Web is how you start. Phone and Watch are how you stay.
Day 3 — the rest of Neptune
- Goals, with a plan attached
- Memory — schedule, preferences, injuries, insights
- Surf Tape — upload a photo, get a read on your technique
- Crew — the people you surf with
What this is for
You can start coaching free right now. No install. Ask about your local. The first messages are free.
iPhone and Apple Watch are the capture layer — start, stop, waves, the session that makes the coach smarter. Get on iOS and we'll email you the App Store link when the listing is live.
The stack, briefly
Next.js and Tailwind on Vercel. Supabase for data and auth. Claude for coaching. Stripe on the web. Swift, HealthKit, and Core Location on iPhone and Watch.
What's next
The web is live. The iOS listing is not, yet. That's intentional. We'd rather send you a working link than a 404.
If you surf and want a coach that knows your spots, your skills, and your goals — start on the web. Partner with it. Then take it to the water.
Follow along on Instagram or start coaching.
Read it. Then take it to the water.