Wanikanjector replaces English words with their Japanese equivalent in kanji using the WaniKani API.

However, there's a catch: By default, only words you've learned from WaniKani are replaced.

Features / Development Progress:

• Enable/disable running automatically when loading a tab.
• Blacklist sites to prevent replacing text.
• Hover over words to see the original text.
• Click words to toggle their language.
• Run on-demand or toggle the language for the entire page upon clicking a button in the extension pop-up menu.
• Optionally ignore learning progress when replacing.
• Optionally replace all meanings of words, not just the primary one.
• Intelligently handle English synonyms.
• Intelligently handle English homonyms.
• Optionally color-coordinate kanji by level (apprentice, guru, etc.).
• Optionally highlight learned kanji on sites originally in Japanese.
• Optionally add furigana to unlearned kanji.
• Import custom vocabulary from outside of WaniKani.
• Hover over words to see hiragana readings.
• Hover over words to see links to dictionary entries.
• Generate a list of all kanji/vocabulary that appears on the page.