RateSync - Sync Letterboxd Rating to IMDb

About

RateSync bridges Letterboxd and IMDb — the two most popular film platforms — so you never have to rate a film twice.

The moment you rate a film on Letterboxd, RateSync automatically submits the same rating to your IMDb account in the background. No extra clicks, no switching tabs, no copy-pasting. Just rate once and you're done on both.

How It Works
You rate a film on Letterboxd (from the film page or the log/diary dialog)
RateSync detects the rating in the background
It looks up the film's IMDb ID via Letterboxd's film data
It submits the equivalent rating to IMDb using your existing IMDb session
The sync is logged in the extension popup — green for success, red for failure
Letterboxd uses a 5-star (0.5 increments) scale. RateSync converts this to IMDb's 10-point scale automatically.

Features
Automatic — works silently in the background, no interaction needed
Sync log — view your recent syncs with film title, star rating, and timestamp
Stats bar — see total synced, success rate, and average rating at a glance
Filters — show only failed syncs or only unique films
Auto-open — optionally open the IMDb page after each sync
TMDb fallback — if Letterboxd doesn't carry a direct IMDb link, RateSync falls back to TMDb to resolve it (requires a free TMDb API token)
Login detection — the status pill in the header shows your IMDb connection state at a glance

Requirements
A Letterboxd account (free)
An IMDb account (free) — must be logged in on the same browser profile
A TMDb API Read Access Token (free) — only needed for films where Letterboxd doesn't carry a direct IMDb link

Privacy & Security
No accounts, no servers — RateSync runs entirely in your browser. No data is sent to any third-party server other than IMDb and TMDb (which is the entire point of the extension).
Your TMDb token is stored locally on your device in Chrome's extension storage and is only ever sent to TMDb to look up film IDs.
Your IMDb session is used directly to submit ratings via IMDb's GraphQL API — the same session your browser already has. RateSync does not store or transmit your IMDb credentials anywhere.
No analytics, no tracking, no ads.

Disclaimer - This extension does not collect any data and is not affiliated with Letterbox or IMDb.