{"about":{"summary":"A directory of side businesses that real people say they run, each summarized in our words and linked to its public source.","notes":["Sources are public, first-person accounts: interviews, podcasts and community threads.","Cost, time and the other tags are machine estimates, each with a confidence score.","Income figures are the owner's own claim. We don't verify them."],"how_to_cite":"Link the idea page and its source. Call income figures the owner's unverified claim, and cost and time estimates."},"idea":{"slug":"gym-app-built-through-constant-testing-c6008e","title":"Gym app built through constant testing","summary":"A gym app whose founder treats product development like a science experiment, using A/B tests and feature validation to decide what to build.","url":"https://allsidehustleideas.com/ideas/gym-app-built-through-constant-testing-c6008e","markdown_url":"https://allsidehustleideas.com/ideas/gym-app-built-through-constant-testing-c6008e.md","tags":{"category":{"value":"software","label":"Software and apps","confidence":0.97},"earns_from":{"value":"subscription","label":"Subscriptions","confidence":0.91},"startup_cost_estimate":{"value":"1k-10k","label":"$1k to $10k","confidence":0.47},"time_estimate":{"value":"part-time","label":"Part-time","confidence":0.5},"where":{"value":"online","label":"Online","confidence":0.97},"needs_coding":{"value":true,"confidence":0.98}},"owner_reported":{"text":"Self-reported by Mauro: $160,000 last month","verified":false},"source":{"publication":"Starter Story","title":"How I Built This $160K/Month Gym App","url":"https://www.youtube.com/watch?v=OV09yPLf8BI","person":"Mauro","host":"Pat Walls","date":"2026-09-09"},"owner_site":"https://symmetry.club/"}}