πόδας ὠκὺς Ἀχιλλεύς
Swift-footed Achilles. Homer's epithet, forty-odd times.
The seven-day week is a habit, not a law.
Achilles reads your body before it reads the calendar. Readiness from your own baseline, a program that progresses itself, a daily pick with a reason, and a coach that has read your data. One app for lifting, running, fuel, and mind.
iOS 26 · Apple Health · Offline-first · Raw health data never leaves the phone
Hephaestus worked the whole world into one shield. Scroll and the bands light.
Why a shield
In Book 18 of the Iliad, Hephaestus forges Achilles a shield and works the whole cosmos onto it in rings: the sun, moon, and Pleiades at the centre; two cities; the ploughing and the harvest; a dance; and the river Ocean around the rim. It is the oldest description of a made thing in Western literature.
We built the app the same way, from the centre out. What you read first is the sky. Then the work. Then the people around the work. Then the edge, where nothing crosses. Every ring below is one part of Achilles and the symbol it was built on.
Πληϊάδων Ἀτλαγενέων ἐπιτελλομενάων
When the Pleiades rise, begin the harvest. Hesiod, Works and Days.
Readiness
Before you train, read the sky. Yours.
Hesiod told farmers to plant by the stars, not by a date. Achilles does the same with your body. Every morning it compares last night to your own rolling thirty-day baseline and gives you one number, 0 to 100, with the reasons underneath. Not a population average. Your sky.
Five inputs, weighted
Heart-rate variability, resting heart rate, sleep duration, sleep quality (deep and REM minutes), and sleep efficiency, each as a z-score against your baseline. Missing metrics reweight; they never fake a value.
Load and adherence
A 7-day over 28-day training load ratio pulls the score down when you have stacked too much, and the past week's completed sets and intervals nudge it either way.
Three bands, no red
Ready, lighten, or rest. Rest is drawn in a calm periwinkle, never red, because rest is a prescribed dose, not a failure state.
Deterministic and explainable
Same inputs, same answer, always. The AI reads this score. It never computes one. Tap the dial and every input is shown against its baseline.
Ἥφαιστος
Hephaestus. The god who made things by striking them again.
The program
Forged, not generated. The same lifts, struck heavier each time.
A smith does not invent a new blade every morning. He returns to the same metal and hits it again. Your program is a small set of core workouts per discipline, repeated on purpose, each one carrying its own numbers forward. Finish a session and the next one is already heavier.
Built from your baselines and goals
One-rep maxes, race times, weekly kilometres, and structured goals per discipline become a weekly plan: upper/lower, push/pull/legs, 5×5 strength days, easy, tempo, threshold, VO2, and long runs sized to what you actually run.
Double progression, in plain rules
Hit every set and the next session adds a rep. Reach the top of the rep window and it adds weight and drops the reps back. Three stalls and it takes ten percent off and starts again. Barbells snap to 5 lb, everything else to 2.5.
Deload on a cadence
Every four to eight weeks, by rule, volume comes down and loads sit around 85 percent so the work you did can land. The badge tells you why.
No AI in the loop
Building, progressing, and recommending are deterministic code with unit tests. The program works with no API key at all. Rebuild it and weeks of earned overload carry forward.
καιρός
Kairos, the opportune moment. Lysippus gave him a forelock and a bald crown: grab him as he comes, or not at all.
Today's pick
The Greeks had two words for time. Calendars only know one.
Chronos is the clock: every hour the same length, every Monday a leg day. Kairos is the right moment, which does not care what day it is. Achilles keeps an open schedule and, each morning, hands you one session with its reasons: what you owe this week, what you did yesterday, what your readiness says, what is adjacent to what.
One pick, with reasons
“Pull day: next in sequence, two lifts still owed this week, readiness green.” Every pick carries its reason codes. You can take it, swap it, or add a second session.
Rest is a headline, not a gap
A red day, a blocked weekday, a long streak, or a finished week puts rest at the top with the why. It never hides a training option underneath.
Adjacency rules
No hard lower-body lift beside a hard run, no two hard days sharing a muscle, no two hard endurance sessions back to back. The sequence holds; the dose trims.
Coming up, today-anchored
A strip of the next seven days projected from today, never a Sunday-to-Saturday grid. Two-a-days pair an easy run with a lift when the week needs them.
Χείρων
Chiron, the centaur who raised Achilles on Pelion and taught him medicine, music, and the hunt.
Daily Pulse · Ask Achilles
A coach who has actually read your data.
Chiron was the wise one among the centaurs, the teacher of Jason, Asclepius, and Achilles. Two features carry his job. The Daily Pulse writes a short, honest paragraph about your day. Ask Achilles answers questions against your real numbers. Neither invents a fact; everything they read was computed first.
The Pulse has no score
Forty-five to seventy-five words, at most two numbers, one concrete thing to do next. An hour on the bike counts as much as steps. It refreshes as the day moves: morning, midday, afternoon, evening.
Ask about your own week
“Was my top set heavier than usual?” “Why am I yellow today?” The coach sees today's sets and intervals, your nutrition targets and meals, a week of readiness with its breakdown, your fast, your stack, your goals.
Generated workouts, when you want one
Ask for a push day or a 6×400 session and it is written against your baselines, your trend, and the catalog of 1,327 real exercises with demonstration clips. Notes must cite the trend they progressed from.
Honest by construction
Fasting stages are called estimates. Supplements and peptides are mentioned, never dosed or endorsed. Nothing diagnoses. The engines judge; the coach explains.
Ἔργα καὶ Ἡμέραι
Works and Days. Hesiod's almanac: when to plough, when to reap, when the Pleiades hide for forty nights.
Nutrition · Fasting · Supplements · Peptides
The harvest band. What goes in, and when.
The outer bands of the shield are the ploughing, the reaping, the vintage, and the herds: the work that feeds the city. The Nutrition tab answers one question, what am I taking and did I take it, and keeps it apart from what am I training.
Targets that move with the day
Calories from your basal rate and a fortnight of real active energy, scaled by your goal and by the day: a hard endurance day eats more, a rest day less. Protein by discipline, fat floored, carbs take the rest. Every number comes with its rationale.
Log a meal three ways
Describe it and the ingredients are parsed into rows you can edit before saving. Scan a barcode. Reuse a saved meal in one tap. Totals read from Apple Health, so other apps count too.
The fast and its forty nights
A fasting clock that stores two instants and derives everything else. Stages are shown as the population estimates they are, and the coach is forbidden from using them to push you longer.
The stack and the protocol
Supplements as one-tap check rows with streaks that forgive a day that is not over. Peptides as events with a dose, a site, and a time, because site rotation is the part everyone loses track of.
γνῶθι σεαυτόν · μηδὲν ἄγαν
Know thyself. Nothing in excess. Carved at the entrance to the temple at Delphi.
The Mind tab
Two maxims on a temple door. One tab.
The Greeks put the centre of the world at Delphi and carved two instructions on the way in. The Mind tab is those two instructions. Know thyself: write the goal, name the obstacle, choose the moment and the smallest next action. Nothing in excess: name the thing you are cutting back on and let the app count honestly.
Intentions, not slogans
Each morning practice is three steps built from goals you wrote yourself: an identity you can claim today by acting, the specific thing that derails it, and an if-then cue. No goals written, no practice invented.
Patterns: what you are cutting back
Alcohol, nicotine, late screens, whatever it is. Raw events in, streaks and trends computed on read, a playbook plan written for your situation. Never persisted, never flattering.
The quit clock
Runs from the last logged use, not the quit date, because that is what you already believe happened. No baseline stated means no money-saved guess. A fed craving with its trigger recorded is worth more than a clean chart.
Urge surfing
A five-minute timer, because a craving builds, peaks, and passes on its own. Either outcome is one tap. These screens never carry an ad.
ἐν δ᾽ ἐτίθει
“And on it he set…” Homer's refrain each time the smith adds a figure.
Figures worked into the bands
The smaller figures, each with its own sign.
Σελήνη
The moon. The Greeks kept time in lunar months.
Cycle tracking
Log a period in one tap and it is written to Apple Health, where it stays. Phase and day are computed on the phone from your own last six cycles; nightly wrist temperature, if you have it, anchors ovulation by the classic sustained-rise rule. Only your current phase reaches the server, as coaching context, and turning it off wipes even that. Never a fertility tool. Never sold or shared.
Κανών
The Canon. Polykleitos measured the body against a rule, then sculpted it.
Progress photos
Every seven days: four guided angles with a countdown and a body outline, each skippable. Photos are screened before they are stored, kept in a private bucket, and deletable one set or all at once. If you opt in, feedback compares this set with the last in the tone you pick, encouraging or direct, and never estimates body fat, weight, or health.
πόδας ὠκύς
Swift-footed. The epithet, earned on the road.
Live run
GPS-guided intervals: rolling pace against the target band, on pace, pick it up, or ease off, steps that advance themselves by distance or time, a route map, and a voice over your music that ducks it instead of fighting it. Splits and average pace fill themselves in when you stop. The rest timer between sets lives on the lock screen and in the Dynamic Island, because the phone is face-down on a bench.
Μυρμιδόνες
The Myrmidons: ant-people, who kept working whatever the weather.
Offline first
Every tap is written on the phone first and carried to the server when there is a path. Log a set in a basement gym, start a fast on a plane, check off the stack with no signal; it all lands later in the order it happened, exactly once. The exercise catalog and your last-known day are cached, so a cold launch with no network still opens on a full home screen.
μῆνιν ἄειδε, θεά
Rage — sing, goddess. The first word of the Iliad.
Goggins mode
The Iliad opens on a single word. So does this mode.
Goggins mode is not a skin. It lowers the readiness thresholds and withholds rest days: the engine greenlights sessions a regular schedule would soften, and the weekly plan carries fewer rests. The score itself is never altered and never hidden. You see the same truth in both modes. What moves is the line for acting on it.
In the app you enter it with a press-and-hold. The teal drains out and the ember bleeds in as you commit. Try it on this page.
Same measurement
Readiness is computed identically: the same z-scores against the same 30-day baseline.
Different line
Bands drop from 67 / 34 to 55 / 20. A 33 that reads rest in Reef reads lighten in Ember.
Fewer rests
The recommender offers rest second instead of first, and tolerates a longer training streak.
δύο πόλεις
Two cities on the second band: one at peace, one at war.
Two skins, one truth
Same layout. Same data. Different temperature.
Reef
Neon teal on cold near-black. Rounded type, viscous motion, explanatory copy.
Orchid
Dusty rose, lavender, sage over plum-cast black. Pastel, not saccharine. Light and dark variants.
Ember
True black, red-orange, heavy caps, snap cuts. Terse second-person copy. Dark only.
Readiness colours are invariant across all three. Ready is always the same teal.
κότινος · δάφνη
The wild olive and the laurel
Pricing
Olympia gave its victors a wreath of wild olive. It cost nothing.
Everything that judges you is free, because it runs on deterministic code that costs us nothing to run. The paid tier buys the parts that cost real money: the coach, the generation, and a screen with no ads on it.
Free
Kotinos
Supported by ads on waits and browse screens. Never on the quit screens, the live trackers, the camera, or onboarding. Health data and ad networks never meet.
$0
- Readiness from your own baseline, every day
- The program: core workouts with automatic overload
- Today's pick and the open schedule
- Strength, endurance, and GPS live-run trackers
- Nutrition targets, barcode scanning, saved meals
- Fasting clock, supplement stack, peptide log
- Cycle tracking, kept in Apple Health
- Intentions, patterns, the quit clock
- Progress photos, captured and compared
- AI: 1 workout generation per 7 days, 1 meal estimate per day, Pulse morning and evening, first photo-set feedback
Pro
Laurel
Billed through the App Store. Cancel in your Apple subscriptions any time. Prices shown in USD and may vary by region.
$9.99
/ month
$69.99
/ year · save 42%
- Everything in Kotinos
- No ads, anywhere
- Unlimited AI workout generation
- Ask Achilles: the coach who has read your data
- The Daily Pulse rewrites as your day changes
- AI meal estimates without a cap
- Photo feedback on every set, in the tone you choose
Free AI allowances reset on rolling windows, not calendar days. A failed generation never counts.
Ὠκεανός
The river at the rim of the shield. Nothing crosses it.
Privacy policy
Your body's raw data stays on your phone. That is the edge of the world.
Homer rims the shield with Ocean, the river that bounds everything. Achilles has the same boundary: heart-rate variability, resting heart rate, sleep stages, temperature, and cycle logs are read from Apple Health on the device and never uploaded. The server sees a small daily summary and the workouts you log. Health data is never sold or shared with third parties.
Effective October 12, 2026 · Achilles
This policy explains what Achilles collects, why, where it goes, and how to delete it. It is written to be read. Where it names a company, it is because your data is processed there.
1. What stays on your phone+
Achilles reads Apple Health (HealthKit) with your permission: heart-rate variability, resting heart rate, sleep and sleep stages, steps, active energy, workouts, dietary intake, and, if you enable cycle tracking, menstrual flow and nightly wrist or basal temperature. Raw samples are never uploaded. Reproductive-health permission is requested separately and only when you turn cycle tracking on.
Cycle predictions are computed on the device. Meals you log are written back to Apple Health, tagged so Achilles can remove them if you delete the meal.
2. What we store on our servers+
Account. Sign in with Apple gives us a stable anonymous identifier and, if you share it, your email. Profile facts you enter: sex, height, weight, timezone, disciplines, baselines, goals, availability, and whether Goggins mode is on.
A daily snapshot. One row per day with derived numbers: HRV, resting HR, sleep duration and quality, steps, active energy, dietary totals, and the readiness score computed from them. If cycle tracking is on, the snapshot also carries your current phase and cycle day, and nothing else about your cycle. Turning cycle tracking off wipes those fields in the same transaction.
What you log. Workouts and their actuals, effort ratings, GPS-derived splits (not the route), meals and ingredients, fasts, supplements and whether you took them, peptide injections (dose, site, time), intentions, patterns you are cutting back on and the events and urges you record, and the goals you write.
Progress photos. Stored in a private per-user bucket on Amazon S3, served through short-lived signed links, kept until you delete them. You can delete a set or everything at any time from the app.
3. Who processes it, and why+
Anthropic (Claude). AI features send a deterministic summary of your day, relevant history, and your question or request to Anthropic's API to produce a workout, a meal estimate, the Daily Pulse, an answer in Ask Achilles, intentions, a pattern plan, or photo feedback. Progress-photo feedback sends the photos themselves. Anthropic processes this data to return a response and does not use API inputs to train its models.
Amazon Web Services. Our API and database hosting, photo storage, and Rekognition, which screens each progress photo for explicit content and confirms a person is in frame before it is stored.
Open Food Facts. Barcodes you scan are looked up against this public database. The barcode is sent; nothing about you is.
Apple. Sign in with Apple and App Store subscriptions. Apple tells us whether your subscription is active. We never see your payment details.
Google AdMob (free tier only). Shows ads in the free version. The ad SDK is never initialised for Pro accounts and never receives health, nutrition, cycle, pattern, or photo data. Ads are never shown on quit or urge screens, live trackers, the camera, or onboarding, and alcohol, gambling, and weight-loss ad categories are blocked.
4. What we never do+
We never sell your data. We never share health data with third parties for their own purposes.
We never upload raw HealthKit samples, period dates, flow logs, or temperature readings.
We never use your data to train AI models, and our processors are bound not to.
We never show ads next to health data, and we never let an ad network know your readiness, your cycle, or what you are cutting back on.
5. Your controls+
Revoke any Apple Health permission in the Health app at any time; Achilles keeps working with what remains.
Delete any workout, meal, fast, log, pattern, or photo set from the app. Deletion is immediate on our servers; backups age out within 30 days.
Disable cycle tracking to wipe derived cycle fields from the server in the same transaction.
Delete your account from Settings to remove everything we hold, including photos. Export is available on request.
6. Retention, security, children+
Data is kept while your account exists. Access tokens are short-lived and refresh tokens rotate. Photos and the database are encrypted at rest.
Achilles is for adults. We do not knowingly collect data from anyone under 18, and the app's peptide, supplement, fasting, and cessation content is written for adults.
7. Changes and contact+
We will post changes here with a new effective date, and tell you in the app when they matter. Questions: privacy@achilles.fitness.
ἐγγύα, πάρα δ᾽ ἄτα
Surety brings ruin. The third Delphic maxim, and the one about promises.
Terms of service
The Greeks carved a warning about guarantees into the temple door. Here are ours.
Effective October 12, 2026
1. What Achilles is, and is not+
Achilles is a training, nutrition, and habit companion. It is not a medical device and does not provide medical advice, diagnosis, or treatment. Readiness scores, fasting stages, cycle predictions, nutrition targets, and quit milestones are estimates built from population guidance and your own history. Talk to a clinician before changing training, diet, or anything you take.
The app counts and reminds. It never doses, prescribes, or endorses any supplement, peptide, or medication. Cycle tracking is for training context and is not a contraceptive, conception, or pregnancy tool.
2. Eligibility and account+
You must be 18 or older. You sign in with your Apple ID and are responsible for activity on your account. One account per person.
3. Subscriptions+
Achilles Pro (“Laurel”) is an auto-renewing subscription billed by Apple at the price shown in the App Store for your region. It renews unless cancelled at least 24 hours before the end of the period. Manage or cancel it in your Apple ID subscription settings. Refunds are handled by Apple under its policies.
The free tier is supported by advertising and by rolling allowances on AI features. Allowance numbers may change; we will say so in the app.
4. AI features+
Workouts, estimates, the Pulse, answers, intentions, pattern plans, and photo feedback are generated by a language model from the data you give us and may be wrong. Review every prescription before you lift it. AI output is not medical, nutritional, or psychological advice.
5. Your content+
You own what you log and photograph. You grant us a licence to store and process it to run the service. Progress photos must be of you. We screen uploads for explicit content and may refuse or remove a photo; repeated violations end the account.
6. Acceptable use+
Do not reverse engineer, scrape, resell, or abuse the service or its AI features. Do not use it to harm yourself or others.
7. Availability and changes+
We may change, suspend, or discontinue features. The app works offline for most things and syncs when it can; we are not liable for data that could not sync because of a device or network you control.
8. Warranty and liability+
The service is provided as is. To the fullest extent permitted by law, we disclaim all warranties and are not liable for indirect, incidental, or consequential damages, or for injury arising from training, diet, fasting, or substances you choose to use. Our total liability is limited to what you paid us in the last twelve months.
9. Termination and law+
You can stop at any time by deleting your account. We can suspend accounts that break these terms. These terms are governed by the laws of the State of [State], United States, without regard to conflict-of-law rules. Questions: legal@achilles.fitness.
Draft for counsel review. Bracketed items are placeholders.