Token Counter & LLM Cost
Paste a prompt, see token counts and estimated cost across Claude, GPT, and Gemini models side by side, before you send it.
Small, sharp tools for AI and web work.
Free developer tools for AI and web work, built by an engineer. Nothing you paste ever leaves your browser.
Conversions run in your browser. Nothing you paste leaves your machine.
LLM Tool Schema Builder
Define a tool in a form and copy correct JSON for Claude and OpenAI function calling, plus raw JSON Schema, all in the browser.
JSON Schema → TypeScript / Zod
Paste a JSON Schema and get TypeScript interfaces plus Zod validators: optional fields, enums, $refs, and more, all in-browser.
HTML Table → Markdown / CSV
Paste HTML with one or more tables and get clean GitHub-flavoured Markdown or CSV, with colspan, rowspan, header rows and links handled in your browser.
CSV ⇌ JSON Converter
Paste or drop CSV and get JSON, or the other way around, with quoting, delimiters, headers, and type inference handled in the browser.
CSV to Parquet
Turn a CSV into a Parquet file in the browser. Types are inferred, nulls stay optional, and you can override each column before download.
Parquet to CSV
Open a Parquet file to see its schema, row groups, and a preview, then export CSV or JSON. Large files are read in ranges, and nothing is uploaded.
Parquet Viewer
Open a Parquet file and view the first 100, 150, or any number of rows with the schema and row count. Read in your browser, nothing uploaded.
HTML to Markdown
Turn any page or pasted HTML into clean Markdown, perfect for docs, README files, and preparing web content as LLM context.
Markdown to HTML
Paste Markdown and get clean, formatted HTML with a live preview. Tables, task lists, and fenced code render just like GitHub.
Markdown to PDF
Paste Markdown and download a PDF of the rendered page. Tables, task lists, fenced code, Mermaid diagrams and LaTeX math, all in the browser.
JSON ⇌ YAML ⇌ TypeScript
Convert config and API payloads between JSON, YAML, and TypeScript interfaces in one place, with auto-detected input.
URL Parser & Builder
Inspect every URL component, edit query params in a table, strip tracking, and copy a correctly re-encoded link, all in-browser.
Markdown Table Generator
Edit cells in a spreadsheet-style grid and get a perfectly aligned Markdown table, with alignment, headers, and CSV import.
Diff Checker
Compare two blocks of text or code and see exactly what changed, line by line, side by side or unified, whitespace-aware.