● Closed beta
Your coach writes first.
Strength, nutrition and a coach who knows your sets, reads your recovery — and writes to you in the morning instead of waiting for you to open the app.
We invite people in batches. No newsletter, and your address goes nowhere else.
The difference
Most apps wait until you open them.
Cox doesn't. It gets in touch because it noticed something. It knows what you did yesterday, how you slept and what has not moved for three weeks — and it tells you before you ask.
In the morning
A short briefing: what is on today and why — measured against your sleep, your heart rate variability and what the week has already cost you.
After the session
It asks how it went — and knows whether that was the planned session or an extra one. What you answer stays attached to the session, not buried in a chat nobody finds again.
When nothing moves
Three sessions without progress on the bench is not a coincidence. Cox spots it, checks your recovery and your weekly volume first — and then proposes what should change.
What you get
Three things that work together.
Strength is the way in. Nutrition joins when you need it. And the coach sees both — which is why it knows why the heavy session isn't going anywhere today.
Strength
271 exercises with movement drawings and a muscle map. Four progression methods. Ten ready-made plans or your own build. The target goes up when you hit it.
Take a lookNutrition
Photograph the label and the numbers are there. Scan a barcode. Balance, protein per meal, carbs around the hard session — without typing figures.
Take a lookThe coach
Briefing, debrief, weekly report. It remembers what you tell it, asks a question now and then — and builds a picture of you over weeks.
Take a lookHow it works
The maths is deterministic. The talking is human.
The numbers do not come out of a language model. Load, recovery, volume, progression — an engine computes those, step by step, and you can open up every one of them. The language model puts the result into sentences and talks to you about it.
Daily: your state against your own baseline
Sleep, heart rate variability, resting heart rate and the load of recent weeks — compared with your own values over the last eight weeks, not with a table for everybody. That is where today's recommendation comes from.
- No single score that nobody can reproduce
- Every figure opens up: what it measures, why it matters now
- Thresholds are yours, not an average person's
The today view. Sample data.
Per session: what you lifted becomes the next target
Every set counts. Weight and repetitions give an estimated maximum, and that becomes the target for next time — following the method you picked for that exercise.
Holds and carries have fields of their own. Seconds do not end up in the repetitions column, where they would corrupt every calculation downstream.
Logging a set in the gym. Sample data.
Per week: volume, plan adherence, patterns
How many hard sets did each muscle group get — and is that inside your productive range or above it? What did you plan, and what actually happened? And which patterns keep repeating?
On Sunday evening the coach sums up the week and sends it to you unprompted.
The week in review. Sample data.
Who it is for
If one of these sounds familiar.
“I have been lifting for two years, but I have no idea whether I am getting better. And my plan is a screenshot off the internet.”
Gym, three to five times a week
“I run, I ride, I go to the gym. I have five apps and not one of them tells me whether all of it together is too much.”
Strength and endurance, job and family
“I have sleep data, heart rate variability, load figures. What I do not have is someone who reads all that and makes a call.”
Already tracking, rarely analysing
And what Cox is not for
- Cox is a wellness companion for your training — not medical advice and not a medical device.
- What Cox says about your readings is not a medical assessment, and it will not tell you what is wrong with you. If something hurts or worries you, that belongs with qualified people near you — not in a chat.
- If you are just starting out and have no access to equipment or weights yet, you will not get much out of this: Cox plans for people who already train.
- No points, no streaks, no leaderboards. Cox compares you with yourself, not with other people.
Connections
Your devices, if you have any.
None are required. Strength and nutrition work with what you enter yourself. If you own a watch or a scale, the coach gets more precise.
Strava is not possible: their API terms forbid processing third-party data with AI — for an AI coach that is not a question of effort but a closed door. Apple Health and Samsung Health have no server API; Cox runs as a web app, not through an app store.
Your data
Hosted in the EU. No ads, no selling, no tracker.
Servers in Germany, database in the Netherlands. This page loads nothing from foreign servers and sets no counting pixel — which is also why it does not ask you about cookies. Your training and body data are processed only with your explicit consent, and you can withdraw it at any time.
Which providers are involved — including the AI models — is set out in full in the privacy policy (German).
Access
Cox is in closed beta.
We invite people in batches so everyone who joins lands properly. Tell us what you train — we will get in touch as soon as a place opens up.
Thanks — we have you on the list.
You will get a short confirmation by email in a moment. As soon as a place opens up we will send your invitation.
Frequently asked
What people ask us most.
Do I need a watch or a scale?
No. Strength and nutrition work entirely on what you enter yourself — sets in the gym, food by photo. If you do supply sleep and recovery data, the daily recommendation gets sharper; without it Cox still plans.
Is this just a chatbot with my training data?
No. Load, recovery, volume and progression are computed by an engine — same formulas, same input, same result, and you can open each one up. The language model turns that into sentences and talks to you about it. It invents no numbers, and it does not decide what you train.
The second difference: Cox does not wait for your question. It writes in the morning, after your session and at the weekend, on its own.
What happens to my data?
Servers in Germany, database in the Netherlands. No selling, no advertising, no tracker on this page. Your training and body data are a specially protected category — Cox processes them only with your explicit consent, which you can withdraw at any time.
For the coach's replies your context goes to an AI model. Which providers those are and what they may do with it is set out in full in the privacy policy (German).
Can I take my data with me again?
Yes. Exporting your data and deleting your account are features, not favours — deleting also deregisters connected data sources. During the beta both still run through an email to [email protected] and are being built out as self-service.
What does Cox cost?
Nothing during the closed beta. Later Cox will become a paid subscription — we will announce that in good time, and nothing becomes chargeable without your explicit agreement. People in the beta hear about it first.
Does it run on iPhone?
Yes. Cox is a web app you add to your home screen — on iPhone, Android and on a computer. No app store, no installation, notifications still work. If you like, the coach can also write to you on Telegram.
I only train strength. Do I need the rest?
No. During setup you say what you train — tick strength only and you get strength only: no endurance plan, no questions about races, no empty pages. Nutrition is a separate module you can add or leave out.
Who is behind this?
Cox is built in Germany by one person, not by a team overseas. It grew out of a coach that originally ran for a single athlete. Who is responsible is stated in the imprint (German); questions go to [email protected] and are answered by a human.
What comes next
Honest, short, no dates.
- In progress — export and account deletion as self-service, movement drawings for the remaining exercises.
- Next — Garmin direct, Oura, a monthly report from the coach.
- Later — open sign-up without an invitation.
As of August 2026. The order may change; we deliberately name no dates.