Privacy Policy — English Vocabulary Highlighter

Last updated: July 16, 2026

Publisher: Miryeong Song (individual developer)
Extension: English Vocabulary Highlighter
Contact: GitHub Issues

Summary

English Vocabulary Highlighter is a local-first browser extension. Your saved words and settings stay on your device. We do not operate a backend server, sell data, or use analytics.

Optional Look up uses third-party APIs only when you select a word and request a definition. Only that selected word is sent.

Data we process

Stored locally on your device (`chrome.storage`)

Data	Purpose
Saved vocabulary entries (word, definition, Chinese translation if any, context, source URL, save time)	Your personal study list
Save counts per word	Show how often you saved a word
Difficulty level toggles (Level 1–4)	Your highlight preferences
Learning mode (Auto / English / Reverse)	Your UI preference

You can delete individual entries or clear all saved words from the extension popup.

Processed temporarily (not uploaded as page content)

Data	When	Purpose
Visible page text	While you browse	Match and highlight vocabulary from bundled word lists (processed on-device)
Sentence around a highlighted or looked-up word	When you double-click to save, or Save word after Look up	Store learning context locally

We do not upload full page content to any server.

Sent only when you use Look up

Data	When	Purpose
The single English word you selected	When you click Look up	Fetch an English definition and a Chinese translation

Data we do NOT collect

No accounts or login
No analytics or tracking
No advertising identifiers
No selling or sharing of personal data
No cloud sync (unless you export files yourself)

Network access

Highlighting uses only files shipped with the extension (vocab.json, zh_vocab.json, zh_translations.json) and needs no network.

Look up (optional) sends the selected English word to:

Free Dictionary API (api.dictionaryapi.dev) — English definitions
MyMemory (api.mymemory.translated.net) — Chinese translation of the word

Only the selected word is sent. Results may be saved on your device if you choose Save word.

After you save a Look up word, the extension re-highlights that word on pages you visit using only your local saved list. Highlighting does not trigger further dictionary or translation requests. Saved Look up words stay highlighted even when level filters are turned off.

Permissions explained

Permission	Why
`storage`	Save your words and settings locally
`activeTab`	Access the current tab URL when you save a word
Access to webpages (content script)	Highlight vocabulary on pages you visit
Host access to dictionary / translation APIs	On-demand Look up only

Data retention

Data remains on your device until you remove it (Clear saved words) or uninstall the extension.

Third-party dictionary and translation providers may process the looked-up word under their own policies for the brief request.

Children

The extension is a general study tool and is not directed at children under 13. We do not knowingly collect personal information from children.

Changes

We may update this policy. The “Last updated” date will change. Continued use after updates means you accept the revised policy.

Your rights (EEA / UK)

Because saved study data is stored locally in your browser, you control it directly: view saved words in the popup, export to Markdown/CSV, or clear/delete entries. For questions, open a GitHub Issue.

Open source

Source code: github.com/serena813/english-vocab-highlighter (MIT License)