Developer tools at a glance

Find every RunTools.dev utility in one searchable catalog, from converters and encoders to DNS, JWT, regex, JSON, CSV, and formatting tools.

Conversion

14

Timestamp Converter

Convert Unix Timestamp to Date and vice versa.

Time Zone Converter

Convert date and time between time zones with daylight-saving awareness.

Date & Duration Calculator

See how many days remain until a date, how long has passed since, and the years and days between two dates with leap years handled.

QR Code Generator

Turn text or URLs into downloadable QR codes.

Convert JSON arrays into CSV, TSV, HTML, or XML.

YAML ↔ JSON Converter

Convert YAML data to JSON and vice-versa with ease.

Convert CSV into Markdown tables or JSON.

Convert XML rows into CSV, TSV, HTML, or JSON.

Number Base Converter

Convert numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36.

Convert length, weight, temperature, and volume units instantly.

Image Format Converter

Convert images between PNG, JPEG, WebP, and AVIF locally or in the cloud.

Roman Numeral Converter

Convert between Roman numerals and Arabic numbers from 1 to 3999 with a live symbol-by-symbol breakdown.

HTML to Markdown

Convert HTML into clean Markdown with lists, tables, links, and fenced code blocks preserved.

ENV to JSON Converter

Convert .env files to JSON and back, with quoting, comments and type parsing handled for you.

Encoding & Cryptography

10

Base64 Converter

Encode and Decode Base64 data.

URL Encoder / Decoder

Keep text from breaking URLs by safely encoding or decoding it.

URL Parser / Builder

Parse a URL into its parts and edit query parameters to generate a new URL.

Create MD5, SHA-1, SHA-256, or SHA-512 digests locally from any text.

Decode JSON Web Tokens (JWT) locally.

UUID / ULID Generator

Generate UUID v4 or ULID identifiers in bulk.

Password Generator

Generate secure random passwords with adjustable strength and length.

Generate and verify HMAC-SHA-256/512 signatures locally.

HTML Entity Encoder

Encode and decode HTML entities in your browser with named, decimal, or hexadecimal output and full emoji support.

Escape and unescape strings for JSON, JavaScript, Java, SQL, CSV, shell, regex, and XML in one place.

Networking

11

Perform DNS lookups (A, MX, TXT, etc.) for any domain.

IP & Location Lookup

See your current public IP, ISP, and approximate location.

CIDR / Subnet Calculator

Enter an IPv4 CIDR to instantly calculate the network address, broadcast address, and host range.

User Agent Parser

Analyze browser, OS, device, and engine details from any user agent string.

Certificate Decoder

Decode PEM X.509 certificates locally and inspect key fields.

Normalize and merge IPv4 CIDR lists into a minimal set.

HTTP Header Parser

Parse raw HTTP header lines, normalize names, and inspect invalid lines quickly.

MIME Type Lookup

Look up MIME types by extension or reverse lookup extensions from MIME names.

HTTP Status Lookup

Search HTTP status codes, filter by class, and review practical meanings quickly.

Expand, compress, and inspect IPv6 addresses with RFC 5952 canonical output, prefixes, and zone IDs.

Port Number Lookup

Search well-known TCP and UDP ports by number, service, or keyword and see what normally listens there.

Developer Utilities

19

Python Beautifier

Format Python with indentation, wrapping, and whitespace controls.

JavaScript Beautifier

Tidy JavaScript with indentation, wrapping, and spacing options.

Markdown Preview

Render Markdown in real time with a clean, readable preview.

Indent and tidy complex SQL so queries stay readable.

Cron Expression Parser

Validate cron schedules and preview upcoming runs.

Test and debug regular expressions with live highlighting.

JSON to TypeScript Converter

Convert JSON into TypeScript interface/type definitions.

Color Converter

Convert between HEX, RGB, HSL, and CMYK and build quick palettes.

Chmod Calculator

Calculate and convert Unix/Linux file permissions between octal (755) and symbolic (-rwxr-xr-x) formats.

Compare two texts with unified or split view, full or incremental context.

Convert strings between camelCase, snake_case, PascalCase, and other common naming conventions.

Count characters, words, and lines instantly.

Lorem Ipsum Generator

Generate realistic placeholder text for mockups and drafts.

JSONPath Tester

Query JSON data locally with a safe JSONPath subset.

Convert cURL commands to fetch, axios, and Python requests snippets locally.

Convert titles or sentences into clean URL-friendly slugs instantly.

Color Contrast Checker

Check the WCAG 2.1 contrast ratio of any color pair and see AA and AAA results instantly.

Sort lines alphabetically or naturally, remove duplicates, and clean up any text list right in your browser.

JSON Schema Generator

Turn any JSON sample into a ready-to-use JSON Schema with types, formats, and required fields.