Free developer, AI and SEO tools that run in your browser
Format and convert JSON, decode JWTs, count tokens, write MCP configs and check meta tags. There is nothing to install and no account to create, and what you paste never leaves your device.
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JSON Tools
Format, validate, explore and minify JSON, and convert it to and from CSV and YAML.
7 tools
Developer Tools
Format XML and SQL, encode and decode Base64, read JWTs and convert Unix timestamps.
5 tools
AI & MCP Tools
Estimate LLM API costs, count tokens, and write or check MCP server configs.
4 tools
SEO Tools
Preview titles and descriptions, generate schema markup, build UTM links and test robots.txt.
4 tools
Popular tools
JSON Formatter & Validator
Format and validate JSON in your browser. Errors point to the line and column with a fix, and big numbers and duplicate keys stay as written.
JSON to CSV
Convert JSON to CSV in your browser: nested objects become columns, long numbers keep every digit, and cells that could run as formulas are escaped.
Base64 Encoder & Decoder
Decode Base64 to UTF-8 text or a file, or encode text and files in your browser. Works with URL-safe Base64, data URIs and PEM, and pinpoints bad characters.
JWT Decoder
Decode a JSON Web Token in your browser: header, payload and claims with their dates, whether it has expired, and warnings for alg none and risky claims.
Unix Timestamp Converter
Convert Unix epoch timestamps to dates and back, in seconds, milliseconds, microseconds or nanoseconds, in any time zone, with daylight saving gaps flagged.
AI Token Counter
Count tokens in your browser: exact for GPT models with OpenAI's o200k_base and cl100k_base tokenizers, estimated for Claude, Gemini, DeepSeek and Mistral.
Why Toolzami
Your data stays on your device
Every tool runs in your browser. What you paste or open is processed locally: it is not sent to Toolzami, not stored and not passed to analytics.
Results as you type
There is no upload and no queue. Text tools update the result after a short pause in typing, and large documents are parsed in a background thread so the page stays responsive.
Free, with no sign-up
Every tool is free to use without an account. Size limits exist only to keep your browser responsive.
Examples you can trust
The examples in each guide are produced by the tool itself and checked on every build, so the documented output is the real output.
More on who makes Toolzami and why: About Toolzami
Frequently asked questions
Is Toolzami free to use?
Yes. Every tool is free and works without an account, a trial or an install.
Does Toolzami upload or store what I paste?
No. The tools process your input with JavaScript in your browser. It is not sent to Toolzami, not saved and not included in analytics, and it is gone when you close the page. Only the options you choose, such as the indentation, are remembered in your browser.
Why do the tools need JavaScript?
Because they run in your browser instead of on a server, which is what keeps your data on your device. The guides, examples and answers on each page are plain HTML and can be read without JavaScript.
Which browsers does Toolzami support?
Chrome and Edge 111 or later, Firefox 114 or later and Safari 16.4 or later, on desktop and mobile. Older browsers can show the pages but may not run the tools.
How large can my input be?
Most tools accept up to 10 MB of text or a 10 MB file; a few, such as the AI Token Counter, take up to 2 MB. Larger input is refused with a message instead of freezing the page.