The latest articles on DEV Community by simonchai-tw (@simonchaitw). https://dev.to/simonchaitw https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4113127%2F732a2e3e-660b-4b6d-b5e0-f4b6020e83d7.png https://dev.to/simonchaitw en simonchai-tw Mon, 07 Sep 2026 05:09:47 +0000 https://dev.to/simonchaitw/how-i-built-bidirectional-google-tasks-microsoft-to-do-sync-on-apps-script-1ago https://dev.to/simonchaitw/how-i-built-bidirectional-google-tasks-microsoft-to-do-sync-on-apps-script-1ago <h1> How I built bidirectional Google Tasks ↔ Microsoft To Do sync on Apps Script </h1> <p>I wanted a small, self-hosted bridge between Google Tasks and Microsoft To Do—not another productivity dashboard or a service that keeps my data forever.</p> <p>The result is <a href="https://github.com/simonchai-tw/tasks-todo-sync" rel="noopener noreferrer">tasks-todo-sync</a>, an open-source Google Apps Script project that keeps both task systems moving in both directions.</p> <h2> Why state sync instead of Zapier? </h2> <p>Manual copying is easy for a day and frustrating for a month. Zapier is great when one event causes one action, but bidirectional sync is different: either side can change, events can arrive out of order, and a task can be edited while the other system is unavailable. Triggers, filters, and deduplication rules become hard to reason about.</p> <p>The script reads both sides, maps task identities and fields, compares the latest known state, and applies necessary creates, updates, or completions. Stored state gives the sync a memory instead of blindly copying every item on every run.</p> <h2> Why Apps Script? </h2> <p>Apps Script runs on a schedule without managing a server; OAuth and project configuration stay with the automation; the code is approachable JavaScript; and logs make API problems inspectable. The trade-off is that you configure credentials and APIs yourself. This is intentionally self-hosted.</p> <h2> MIT, with honest limits </h2> <p>The project is released under the MIT license. It is not a promise of perfect conflict resolution: API quotas, token expiry, renamed or deleted lists, transient failures, and provider-specific fields are real constraints. Back up important data and test with a small task set first.</p> <p>If this is useful, a <a href="https://github.com/simonchai-tw/tasks-todo-sync" rel="noopener noreferrer">soft star on GitHub</a> helps others find it. Feedback is welcome: <a href="https://github.com/simonchai-tw/tasks-todo-sync" rel="noopener noreferrer">repo and setup notes</a>.</p> opensource productivity javascript tutorial