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Fast Text Format

Fast Text Format Tools

The ultimate collection of lightning-fast utilities to format, convert, and streamline your workflow.

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Code & Formatting

Base64 to File Decoder

Decode Base64 strings or Data URIs back into downloadable files (images, PDFs, documents, audio) with instant live preview.

Code Beautifier & Minifier

Beautify, validate, and minify your JSON, JavaScript, CSS, and HTML code into clean, readable syntax.

Config Converter (TOML / INI / .env / JSON)

Convert configuration files seamlessly between TOML, INI, Java .properties, .env, YAML, and JSON formats with nested key flattening and unflattening.

CSS Formatter & Minifier

Format, beautify, validate, and minify CSS code with custom indentation.

CSS Visual Generators

Visually generate and export CSS code for Box Shadows, Gradients, Flexbox, and Grid layouts.

CSV to JSON/SQL

Convert CSV data to JSON arrays or SQL INSERT statements.

cURL to Fetch

Easily convert cURL commands into JavaScript Fetch API code.

Docker Run to Compose

Convert docker run CLI commands into clean, production-ready docker-compose.yml configuration files.

GraphQL Explorer & Formatter

Beautify, minify, validate, and inspect GraphQL queries, mutations, subscriptions, and SDL schemas with AST operation & variable analysis.

HTML & XML Formatter

Beautify, format, and minify HTML and XML code with customizable indentation and syntax cleanup.

HTML to JSX

Client-side tool to transform HTML tags/attributes into React-compatible JSX.

HTML to Tailwind CSS

Convert standard inline styles and CSS declarations into Tailwind CSS utility classes with live preview.

JS Obfuscator

Transform readable JavaScript code into unreadable, minified code to protect logic.

JSON Stringify & Parse (.env Ready)

One-click minify and stringify multi-line JSON objects into escaped strings ready for .env files, CLI args, or code literals, or parse escaped strings back into formatted JSON.

JSON to Code

Convert JSON objects into typed models for various languages.

JSON Tree Viewer

Visually inspect, expand, collapse, search, and filter complex JSON payloads with path inspection.

JSONPath & JQ Evaluator

Query, filter, extract, and transform JSON payloads in real-time using standard JSONPath (RFC 9535) or JQ-style expressions with table and visual path views.

Markdown Editor & Previewer

Write, edit, and preview Markdown in real-time with live HTML preview, syntax styling, and HTML export.

Semantic JSON Diff

Compare two JSON documents semantically, ignoring key ordering, formatting, and whitespace differences, with visual change highlighting and RFC 6902 JSON Patch export.

Source Map Viewer

Client-side tool to upload a .map file and de-minify stack traces.

SQL Formatter

Format, beautify, and minify SQL queries across multiple SQL dialects.

String Escape & Unescape

Safely escape (and unescape) quotes, backslashes, and newlines for use in JSON strings, SQL queries, HTML, and Java/C#.

SVG Optimizer

Minify and clean raw SVG code.

SVG to PNG/WEBP

Client-side tool utilizing an HTML canvas to rasterize SVG code or files into downloadable images.

XML Utilities

Format and minify XML strings.

YAML <-> JSON

Instantly convert between YAML and JSON.

Data & Crypto

Generators & Utilities

ASCII Art Generator

Convert text into stylish ASCII art banners, figlet typography, and decorative monospace text.

Barcode Generator

Client-side tool using a canvas to generate linear barcodes (UPC, EAN, Code39) from text.

CHMOD Permissions Calculator

Calculate, convert, and inspect Linux file permissions with visual octal and symbolic modes.

Color Contrast

Check WCAG color contrast accessibility.

Color Converter & Picker

Pick colors and convert between HEX, RGB, HSL, HSV, and CMYK formats with live preview and palette tools.

Cron Expression Builder & Decoder

Build, edit, and decode cron schedules into human-readable descriptions with upcoming execution dates.

EXIF Data Viewer & Stripper

View, inspect, and strip EXIF, camera, and GPS location metadata from JPEG, PNG, and WebP images locally for complete privacy.

Favicon Generator

Convert standard images into universally compatible .ico files and generate standard web app icon sizes.

Image Base64

Convert image files into Base64 Data URI strings and CSS background-image properties.

Image Color Palette Extractor

Drop any image to extract its dominant HEX, RGB, and HSL color palette client-side, with interactive image eyedropper and one-click CSS variables, Tailwind, and JSON export.

Image Compressor

Compress and optimize JPEG, PNG, WEBP, and AVIF images locally in your browser.

Lorem Ipsum Generator

Generate customized dummy placeholder text by paragraphs, sentences, or words for mockups and designs.

Markdown Table Generator

A visual grid editor that allows users to easily add rows/columns and instantly outputs perfectly formatted Markdown table syntax.

Meta Tag & Open Graph Generator

Generate and visually preview SEO meta tags, Twitter Cards, and Facebook Open Graph tags.

Mock Data Generator

Generate hundreds of rows of fake test data (names, emails, addresses, dates, credit cards) and export it as CSV, JSON, or SQL INSERT statements for database testing.

Password Generator

Create strong, secure passwords and passphrases using customizable cryptographic algorithms.

PDF Toolkit

Merge, split, extract, rotate, and reorder PDF pages 100% locally in your browser.

QR Code Generator

Create scalable, customizable, and scannable QR codes from text or URLs with instant download.

Regex Tester & Builder

Test regular expressions with real-time match & capture group highlighting, syntax explanation breakdown, and multi-string test modes.

Robots.txt Generator

Build valid robots.txt rules, crawler directives, and block AI scrapers.

UUID / GUID Generator

Instantly generate universally unique identifiers (UUID/GUID v1, v4, v7) in bulk with custom formatting.

XML Sitemap Generator

Construct valid XML sitemaps with custom URLs, change frequencies, and priorities for search engines.

Finance & Units

Networking

CSR & X.509 Certificate Decoder

Decode PEM/DER X.509 SSL certificates and PKCS#10 Certificate Signing Requests (CSRs) to inspect Subject, Issuer, SANs, public keys, validity, and SHA-256 fingerprints offline.

Cryptographic Fingerprints (DER Digest) Awaiting Input
SHA-256: -
SHA-1: -
Decoded Certificate / CSR Details
Offline ASN.1 Parser
Subject Distinguished Name (DN)
Common Name (CN): -
Organization (O): -
Org Unit (OU): -
Locality / State: -
Country (C): -
SANs (DNS / IP): -
Issuer & Validity Period
Issuer CN: -
Issuer Org: -
Not Before: -
Not After: -
Serial Number: -
Version: -
Public Key & Signature Algorithm
Public Key Alg: -
Key Size / Curve: -
Signature Alg: -
Basic Constraints: -
X.509v3 Extensions & ASN.1 DER Structure 0 bytes
Paste a PEM certificate or CSR or click a sample button to inspect its ASN.1 DER tree.

How to Use

Paste a PEM-encoded X.509 certificate (-----BEGIN CERTIFICATE-----) or PKCS#10 Certificate Signing Request (-----BEGIN CERTIFICATE REQUEST-----), or drop a .crt, .cer, .pem, .der, or .csr file. The ASN.1 DER parser extracts all distinguished names, SANs, extensions, and cryptographic fingerprints locally.

Frequently Asked Questions

What is an X.509 digital certificate?

An X.509 certificate is a standardized cryptographic document (RFC 5280) that binds a public key to an identity (such as a domain name, organization, or server) via a digital signature issued by a trusted Certificate Authority (CA).

What is a PKCS#10 Certificate Signing Request (CSR)?

A CSR (RFC 2986) is a block of ASN.1 DER-encoded text generated on your server before ordering an SSL/TLS certificate. It contains your Subject Distinguished Name, requested Subject Alternative Names (SANs), and your public key, signed by your corresponding private key to prove possession.

Why are Subject Alternative Names (SANs) critical for modern browsers?

Modern browsers (Chrome, Firefox, Safari) deprecated relying on the Subject Common Name (CN) for domain matching per RFC 2818. Every valid HTTPS certificate must list all covered DNS hostnames, wildcards, and IP addresses inside the X.509v3 Subject Alternative Name (OID 2.5.29.17) extension.

What is the difference between PEM and DER certificate formats?

DER (Distinguished Encoding Rules) is the raw binary representation of an ASN.1 data structure. PEM (Privacy-Enhanced Mail) is simply the exact same DER binary encoded in Base64 and wrapped between -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- ASCII headers.

How are SHA-256 and SHA-1 certificate fingerprints calculated?

A certificate fingerprint (or thumbprint) is computed by hashing the entire raw binary DER byte array of the certificate using SHA-256 or SHA-1. It uniquely identifies the exact certificate for pinning, trust store verification, and revocation checks.

What is ASN.1 (Abstract Syntax Notation One)?

ASN.1 is an interface description language used in cryptography and telecommunications to define nested data structures (SEQUENCE, SET, OBJECT IDENTIFIER, OCTET STRING, BIT STRING, UTCTime) serialized into compact Type-Length-Value (TLV) byte streams.

What does the Basic Constraints extension (CA:TRUE vs CA:FALSE) do?

The Basic Constraints extension (OID 2.5.29.19) specifies whether the certificate subject is permitted to act as a Certificate Authority (CA:TRUE) and sign subordinate certificates, or if it is strictly a leaf end-entity certificate (CA:FALSE) that cannot issue further certificates.

Should I ever paste my Private Key into a certificate decoder?

No. Certificates (.crt/.pem) and CSRs (.csr) contain only public information and your public key. Your private key (-----BEGIN PRIVATE KEY-----) must remain strictly confidential on your server or hardware security module.

How can I verify that my CSR contains the right SANs before submitting to a CA?

Paste your -----BEGIN CERTIFICATE REQUEST----- block into this decoder. Our parser inspects the PKCS#9 extensionRequest attribute (OID 1.2.840.113549.1.9.14) inside the CSR and lists every requested DNS name and IP address before you submit it to Let's Encrypt, DigiCert, or Sectigo.

Does this X.509 and CSR decoder send my certificates to an external backend?

No. All Base64 decoding, binary ASN.1 DER TLV parsing, OID resolution, and SHA-256/SHA-1 digest calculations happen 100% locally inside your browser using native JavaScript and Web Crypto.

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