Base64 Encoder / Decoder
UTF-8 safe. Runs locally in your browser.
Using AI? Optimize your prompts first.
Better prompts = better output = fewer revisions.
Try the Prompt Optimizer — Free →You might also like
URL Encoder Decoder
Encode and decode URL strings. Component and full URL encoding. Free.
JSON Formatter
Format, minify, and validate JSON data instantly. See stats for keys, depth, and size. Free.
HTML to Markdown Converter
Convert HTML to clean markdown. Remove tags, keep formatting, save 20-50% on tokens. Free, runs in your browser.
AI Prompt Optimizer
Paste any AI prompt and get an optimized version using the ICCSSE framework. Works for ChatGPT, Claude, and Gemini. Free, no signup, runs in your browser.
100% client-side where applicable — your files and inputs stay in your browser. Nothing is uploaded to HundredTabs servers for these tools.