01
Generic plans aren't built for you
A challenge designed for millions was never designed for your body. When it doesn't work, you blame yourself instead of the plan.
BY DAY
Stop guessing what actually improves your health.
You've tried the tips, the challenges, the routines. Something might have worked, but you don't know what, or why. By Day gives you a structured way to test one change at a time, track real health data, and finally see what moves the needle.
- One change at a time
- Real health data, not guesswork
- See results in 7-21 days
Founding members get lifetime access. Claim your spot.
No spam. Just your beta code and occasional updates. Already have an account? Sign in.
Sound familiar?
You've tried everything. You just don't know what worked.
Cold showers. Magnesium. Screen curfews. Walking 10k steps. You stuck with it for a couple weeks and then... was your sleep actually better? Was it the supplement or the routine? You're not lazy. You just never had a way to close the loop.
02
"Feeling better" isn't data
Without tracking real metrics like sleep, HRV, and heart rate, you're guessing whether a change is actually working or just feels like it.
03
Nobody gives you a system to test
You need structure, measurement, and a clear before-and-after. Not another tip list. By Day is the system that was missing.
Here's how By Day works
One goal. One sprint. Real answers.
A sprint is a focused 7-21 day program with a daily checklist and health tracking built in. Pick a proven program or design your own experiment. Either way, you'll know what worked.
01
Pick a sprint, or build your own
Start with a proven program for sleep, focus, energy, or stress. Ready to test your own ideas? Create a custom experiment around any lifestyle change.
02
Follow a daily checklist
Each day gives you 3-6 focused tasks, 10-30 minutes. No guessing. The plan is built, the order is set, every step has a reason.
03
Track what actually changes
Connect Apple Health or Oura to see real metrics move: sleep, HRV, resting heart rate, activity. No wearable? Track how you feel instead.
04
Keep what works. Drop what doesn't.
Each sprint ends with clear before-and-after data. Double down on what moved the needle, discard what didn't, and start your next experiment.
See it in action
Your experiments and health data in one workspace
Run experiments on mobile or web. The dashboard gives you the full picture: daily tasks, health trends, and before-and-after results across every sprint.
Starter experiments
Start with a proven program.
Not sure where to begin? These experiments are pre-designed and evidence-backed. Pick one, run it for 7-21 days, and see the results. When you're ready, build your own.
Goal
Cadence
Intensity
Sprint pages
Learn more about each sprint before you get started.
Why it works
Small experiments compound into real change.
You don't need a complete lifestyle overhaul. You need one focused experiment at a time, with data to tell you what worked.
01
Focused, not fragmented
One goal at a time. One sprint. 7-21 days. You're not trying to fix everything at once. You're testing one hypothesis and seeing what happens.
02
Data closes the loop
Apple Health and Oura track sleep, HRV, heart rate, and activity automatically. You see real before-and-after numbers, not just how you feel.
03
Each experiment informs the next
Finished a sprint? The data tells you what worked. Keep those habits, drop what didn't, and design your next experiment with better information.
Access
Get started in three steps.
Request a beta code, create your account, and start your first sprint. Lifetime Explorer access is included while early spots are available.
Step 1
Request your code
Enter your email and we will send you a beta access code.
Step 2
Create your account
Use the code when you sign up, or sign in if you already have an account.
Step 3
Start your first sprint
Pick a health goal, follow a daily plan, and track your progress.
Live now
Explorer
Lifetime founding access while spots last.
197 of 200 spots left
During beta Free Full Explorer access included with your beta code.
After beta ends
$8.99 /month
$84 /year
Save $23.88 versus monthly
- Guided sprints + custom experiments
- Apple Health + Oura integration
- Health trends + before-and-after data
- Streaks, XP, and daily momentum
- One account across web and mobile
Founding members who join during beta keep lifetime Explorer access at no cost. Once beta closes, new signups pay $8.99/mo or $84/yr.
FAQ
Common questions
Quick answers to help you decide if By Day is right for you.
Seeing this page as a health data tracker.