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Developer tools for AI engineering
Calculators, analyzers, and utilities for building with LLMs. Everything runs in your browser — no signup, and your data never leaves your machine.
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Calculators, analyzers, and utilities for building with LLMs. Everything runs in your browser — no signup, and your data never leaves your machine.
Count GPT and Claude tokens in any text — free, instant, and it never leaves your browser.
Tokens & ContextSee how your system prompt, history and files fill a 200k window — and when you overflow.
Tokens & ContextConvert between tokens, words, characters and pages with per-language ratios.
Tokens & ContextEvery major model's context window, max output, price and speed in one sortable table.
Tokens & ContextStrip token waste from prompts — whitespace, markdown decoration and duplicate lines.
Tokens & ContextDrop a Claude Code or OpenAI session file and get a per-turn token and cost breakdown.
Tokens & ContextRender your markdown with a heatmap showing exactly which blocks burn the most tokens.
Tokens & ContextSee how retrieval accuracy degrades as context fills, using published benchmark data.
Tokens & ContextSee how much summarizing conversation history every N turns saves on long sessions.
Tokens & ContextJSON versus YAML versus minified: the token cost of the same data in each format.
Tokens & ContextAllocate a token budget across identity, rules, examples and tools — see what fits.
Tokens & ContextSliding window versus running summary: token and cost math for chat memory designs.
Tokens & ContextHow many more tokens the same text costs in 20+ languages, with live samples.
Tokens & ContextThe same function tokenized across Python, JavaScript, Go and Rust — compared.
Tokens & ContextVisualize chunk size and overlap on your document — chunk count, waste and query cost.
Tokens & ContextConvert tokens per second into words per minute, pages per hour and time-to-read.
96 tools live · across 5 categories — all free, all client-side.