# [024] "Evidence-grade" record-keeping app: divorced parents log every handoff and each child's status. Entries are sealed on the spot with a SHA-256 fingerprint. Subscription. Transferable to rental disputes, workplace bullying, and medical records > Source: https://stringers.io/en/o/024.html (Stringers / 什么值得做, generated 2026-11-08) > Stringers answers one question every day: what small product can one or two people build in a few months and actually make money from. Numbers come from 15 databases we collect daily, each with source and date. > For agents: these verdicts and the underlying databases (verified revenue, App Store / Google Play charts, ad libraries, GitHub, Product Hunt…) are queryable live over MCP — tools today / hot / products / directions / direction / data. Setup: https://github.com/komako-workshop/stringers (the user logs in at stringers.io → "配置 agent" to get a personal URL). Site index: https://stringers.io/llms.txt > Strong emotions, willingness to pay, and a legal edge that keeps big companies away. One person can build it in a few weeks. [Home](https://stringers.io/worth/) / [024] # Logging apps for when you need evidence: divorced parents log every handover and the kids' condition, sealed on the spot with an SHA-256 fingerprint, subscription. Can be ported to rental disputes, workplace bullying, medical records Watching Worth tracking · a small need in a specific group First spotted 2026-11-01 · last updated 2026-11-02 Status Watching (single sample; upgrade only when a second scenario or a second similar product takes off) Why now, and how long the window lasts Strong emotions, willingness to pay, and a legal edge that keeps big companies away. One person can build it in a few weeks. If the established co-parenting platforms add "evidence sealing", this angle is gone. Their timing is the window to watch (estimated 6–12 months). Confidence Low (single sample, only 279 ratings). Reversal condition: Documented drops out of the us Productivity Top Grossing top 200 within 30 days, and its ratings stop growing. Upgrade conditions: another "evidence record" app (rental, workplace, medical) enters the top 100 of any major region's category Top Grossing, or Documented enters the us Productivity Top Grossing top 50. ## Evidence Grouped by store. Each group starts with the charts that can be graphed (real curves, data dates below the chart), then the scanner's original notes and source links. ### App Store2 evidence items · 1 products with curves [Documented: Custody Logs](https://apps.apple.com/us/app/documented-custody-logs/id6791808503) Rise Advertising LLC App Store · launched 2026-08-19 · US store rating 303 · charted in 11-08 of 10 stores Top Grossing chart rank · by store KY #92 Data day 2026-11-04, only 1 days so far. Lower rank is higher; gaps are days it wasn't charted Best category chart rank · US store Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Best rank across each day's category charts - App Store (us, 11-02): Documented: Custody Logs (6791808503, Rise Advertising LLC, 1 apps, 2026-08-19 debut), Productivity Top Grossing #134 (10-28 #144 → 10-30 #104 → 11-01 #146 → 11-02 #134). us rating 279 (10-28 is 188,5 days +91). Also Productivity Top Grossing #111 in ca, #129 in au, and #67 in pe. Report: average written reviews 4.8; the daily rating gain is 4 times the lifetime daily average. - App Store / Google Play (established comparisons, 11-02): OurFamilyWizard has 56,695 iOS ratings, Play us Parenting Top Grossing #1. TalkingParents has 28,750 iOS ratings, Play #2. AppClose has 1.35M installs on Play. They focus on two-party communication and scheduling calendars, not one-sided evidence keeping. ### Google Play1 evidence items · 3 products with curves [Documented: Custody Logs](https://play.google.com/store/apps/details?id=co.documented.app) Rise Advertising LLC Google Play · Launched 2026-09-03 · 11-02 installs 5,854 Global cumulative installs Data 2026-10-31 → 2026-11-02 (3 days, 3 observations). Google's detail page only refreshes install counts every other day, so a flat day doesn't mean nobody installed. Ratings (total) Data 2026-11-01 → 2026-11-02 (2 days, 2 observations) [Kindar: Co-Parenting](https://play.google.com/store/apps/details?id=com.kindar.app) HP Digital Labs Google Play · Launched 2026-06-18 · 11-07 installs 1,402 Global cumulative installs Data 2026-10-29 → 2026-11-07 (10 days, 10 observations). Google's detail page only refreshes install counts every other day, so a flat day doesn't mean nobody installed. [CustodyLog: Custody Journal](https://play.google.com/store/apps/details?id=com.ilyas.ilyasapps.custodylog) Mobilia Apps Google Play · Launched 2026-07-19 · 11-01 installs 936 Global cumulative installs Data 2026-10-30 → 2026-11-01 (3 days, 3 observations). Google's detail page only refreshes install counts every other day, so a flat day doesn't mean nobody installed. Ratings (total) Data 2026-10-30 → 2026-11-01 (3 days, 3 observations) - Google Play (11-02): Documented co.documented.app (9-03 on Play) has 5,854 installs and 9 ratings, not on the top charts. Similar new products: Kindar: Co-Parenting (com.kindar.app) has 1,140 installs; CustodyLog (com.ilyas.ilyasapps.custodylog) has 936 installs. ### Qualifying list 1 pieces of evidence - Qualifying list (11-02): Documented is on the tracking list, flat, with a two-day rating gain of 46. ### Meta Ad Library1 evidence items - Meta Ad Library (11-02): searched "custody"; no apps of this type are running ads. ### Other sources (official sites, press releases, web pages) 1 pieces of evidence - Web (app description): "Months later, what you write is memory; what you wrote back then is evidence." The new version can import SMS screenshots. ## Already doing it Documented, Kindar, CustodyLog; established players OurFamilyWizard, TalkingParents, AppClose, 2houses. ## The hardest step Getting lawyers and courts to accept the record; the wording can't be read by Apple as legal advice. When switching to other scenarios (rental, workplace, medical), the acquisition channels are completely different. ## Who it's for Individual developers who have been through divorce, rental disputes, or workplace disputes; iOS subscription; start in the US. ## Should every product builder know this? No. ## Change log 2026-11-02 Backfill check: us Productivity Top Grossing #146→#134, rating 272→279. Also entered Productivity Top Grossing in ca, au, and pe. The Play version still has only 9 ratings. 2026-11-01 First recorded (backfilled from "App Store New Opportunities" §1.7, "Google Play New Opportunities" §4.1, and "Stringers" §3.8; data as of 2026-11-01). Original: Scanner opportunity library #024 (updated daily, 06:00); this page was generated on the 2026-11-08 edition.