FREE · LOCAL-FIRST · NO SIGNUP

Free tools that run entirely in your browser

33 calculators and developer utilities across 9 domains. Nothing is uploaded, nothing is stored, and nothing asks you to sign up.

Browse all 33 tools

JSON Formatter — live

{"name":"ToolAtlas","tools":14,"localFirst":true,"domains":["data","text","calc"]}

{
  "name": "ToolAtlas",
  "tools": 14,
  "localFirst": true,
  "domains": [
    "data",
    "text",
    "calc"
  ]
}

Browse by domain

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Data & Format

Formatting, validation and conversion for structured data such as JSON, YAML, XML, CSV and TOML.

1 category · 8 tools

Text & Encoding

Word counts, character checks and other text statistics for writers and editors.

1 category · 1 tool

Calculation & Conversion

Loan, money and unit calculators for everyday decisions.

2 categories · 13 tools

Web & Network

URL, query string, HTTP and front-end debugging tools.

1 category · 1 tool

Images & Media

Image compression, format conversion and media processing tools.

2 categories · 4 tools

Date & Time

Timestamp, timezone and date calculation tools.

1 category · 1 tool

Encoding & Escaping

Escape, unescape and encode text and structured data — JSON string escaping, Base64 and character encoding, all in your browser.

1 category · 3 tools

Documents & Files

Merge, split and rearrange PDF documents in your browser — the file is read locally and never uploaded.

1 category · 1 tool

Security & Privacy

Generate and check credentials, and other privacy-first tools that run entirely in your browser.

1 category · 1 tool

Popular tools

JSON Formatter reparses your text with a strict JSON parser and prints it back with two-space indentation, so the result is what a conforming parser actually understood rather than a brace-matching guess. Invalid input reports the line and column where parsing stopped. Nothing is uploaded.

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Word Counter

Word Counter tallies words, characters, sentences and paragraphs the moment you type, and compares the totals against the character ceilings that matter for publishing — a tweet, a meta description, an ad headline. Nothing is uploaded.

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Extra Payment Mortgage Calculator

Extra Payment Mortgage Calculator shows what happens when you pay more than the scheduled amount on a loan: every extra dollar aimed at principal shrinks the balance, so future interest is lower and the loan ends sooner. Nothing is uploaded.

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The full index: 33 tools

Every tool on the site, grouped by domain and filterable as you type. Or press⌘K to search from anywhere.

Open the tool index

Why you can trust these tools

Nothing leaves your browser

Every calculation runs on your own device. Nothing is sent to a server, and nothing is logged.

Open it and go

No account, no install, no waiting. The pages are static, so anything you have opened keeps working offline.

Free, and no tracking

No paywall and no analytics scripts. Apart from the one labelled sponsor slot, there is no commercial noise.

Frequently asked questions

Do I need an account or a payment to use these tools?

No. Every tool is free and open, with no signup, no login and no usage limit.

Is the data I paste uploaded anywhere?

No. Everything is processed inside your browser. Nothing is sent to a server and nothing is stored.

Can I use the tools offline?

After the first visit your browser caches the pages, so any tool you have already opened keeps working without a connection.

How do you decide which tools to build next?

Priority goes to jobs a chat window handles badly and that need real interface work: structured validation, side-by-side comparison, format conversion.