Data Diet Coach
A family-facing mobile usage coach that pulls from carrier APIs or manual check-ins, shows who in the household is burning through their GB, and recommends when to upgrade, downgrade, or switch carriers entirely.
Japanese families and couples sharing or comparing mobile plans
- Per-line usage breakdown that flags a teen streaming past 30GB or a parent under-using 6GB
- Recommendations for switching to ドコモmini vs ahamo when usage drops or spikes
- End-of-cycle 'left on the table' report showing how much data was wasted due to no rollover
- One-tap export of usage proof when requesting a plan change at a Docomo shop
ahamo and ドコモmini just added permanent extra GB but explicitly forbid carry-over, so households have a fresh reason to re-evaluate whether their plan matches their usage.
Multiple Japanese tech blogs already publishing ahamo/ドコモmini 10GB boost guides (tinpanblog, jetstream, k-tai.watch) and carrier-comparison searches trend strongly, indicating fresh household interest in re-evaluating plans.ahamoデータ増量キャンペーン8月1日開始｜40GBになる条件 ↗ドコモ「ahamo」が10GB増量で40GBに、「ドコモmini」も増量 ↗
My docomo app is single-user, single-carrier and shows only own usage; no clear cross-carrier family coach product surfaced — but general price-comparison sites (価格.com-style) and carrier switch portals already compete for the same household re-evaluation moment.My docomo - 料金・通信量の確認 - Google Play のアプリ ↗Comparing Mobile Plans in Japan: Save on Phone & Data Bills ↗
Japanese consumers have free first-party tools (My docomo, my daiz) plus established comparison portals; affiliate kickbacks on carrier switches are small and plan-switching happens infrequently, making paid subscription hard to justify.料金やデータ通信量の確認をもっと見やすく便利に| my daiz（マイデイズ） ↗
Underlying need (household plan optimization) is durable because Japan carriers adjust pricing every 1-2 years (ahamo, povo, LINEMO, Rakuten waves), but the specific 'permanent extra GB no carry-over' trigger is one campaign window.ドコモからのお知らせ : 「ahamo」「ドコモ mini」向け「データ増量おためしキャンペーン」 ↗
Japanese carriers do not expose customer usage/billing APIs to third parties — the original docomo developer programme is dead and current GSMA Open Gateway / Aduna network APIs are for telecom-side services, not subscriber data — so the product would need to rely on manual check-ins or fragile screen-scraping of My docomo / My au / My SoftBank.ntt-docomo/README.md at main · api-evangelist/ntt-docomo ↗