About TextFit
TextFit is an AI endurance coach for iPhone and Android, built for self-coached athletes whose plan has to survive a normal week: a late meeting, a work trip, a cold, a bad night’s sleep.
Who makes it
TextFit is made by 01 Apps, a one-person studio in Lithuania. The person who writes the code also writes the guides on this site, answers support@textfit.app, and does the intervals. There is no content team and nothing here is written to fill a calendar.
Why it exists
Self-coached runners, cyclists and triathletes usually choose between two bad options. A static plan from a PDF or an app breaks the first time life gets in the way. A human coach adapts, but costs more than most amateurs want to pay every month.
TextFit started as a tool that turned a workout you typed into a structured workout on your watch. Building one workout turned out to be the small problem. The bigger one is the week: what to do, on which day, and what to change when the week falls apart. So TextFit became a coach. It plans run, bike, swim and strength sessions in one week, puts them on your Garmin or Apple Watch, reads back what you did, and changes the plan when you tell it what changed.
How it stays sensible
The AI writes, explains and adapts the plan. Fixed training rules keep it safe: about 80% easy, at most two hard days a week and never back to back, no more than 10% extra volume a week, and a recovery week every fourth week. A deterministic validator checks every week, and numbers like training load and Fitness, Fatigue and Form are computed in code rather than guessed. Read how the coach builds a week.
How the guides are written
Training guides are checked against published sources, and device how-tos against the manufacturer’s own documentation. If something is wrong, email and it gets fixed.