Free Developer Tools
Looking for free developer tools online? This collection highlights Fneno utilities you can run instantly — no signup required for everyday use. For the curated editorial shortlist, see our best-of page for this topic.
⭐ Featured tools
All tools in this collection
Apache Redirect Rules
301/302 htaccess redirect builder
Arabic SEO Slug Generator
Create URL-friendly slugs for Arabic content
Article Schema Generator
NewsArticle / BlogPosting JSON-LD
Base64 Image Encoder
Image ↔ Base64 data URLs
Breadcrumb Schema Generator
BreadcrumbList structured data
Changelog Generator
Keep a Changelog markdown export
chmod Permission Calculator
Convert octal ↔ symbolic file permissions
ClaimReview Schema
Fact-check ClaimReview JSON-LD
CORS Preflight Checker
Test OPTIONS preflight & CORS headers
Course Schema Generator
Course / learning JSON-LD
Credit Card Luhn Validator
Validate card numbers with Luhn algorithm
Cron Expression Explainer
Human-readable explanation of cron schedules
Cron Expression Generator
Build and validate cron schedules with a visual editor
Cron Next Runs
Preview next scheduled cron executions
Cron Timezone Converter
Cron UTC ↔ your timezone
CSP Header Generator
Content-Security-Policy header builder
CSR Generator
Certificate Signing Request PEM
CSS Formatter
Format, beautify, and minify CSS stylesheets
CSS Minifier
Minify stylesheets for production
CSV ↔ JSON Converter
Convert CSV tables to JSON and back
CSV to JSON Converter
Parse CSV rows into JSON array
CSV to Markdown Table
Convert CSV rows to MD tables
cURL Command Builder
Build curl commands with headers & body
Data URI Generator
Build data: URLs for CSS/HTML
Dataset Schema Generator
Open data / dataset JSON-LD
DNS Lookup Tool
Look up A, MX, CNAME, TXT and more DNS records for any domain
DNS Record Reference
A, CNAME, MX, TXT examples & builder
Docker Compose Generator
Starter docker-compose.yml
Dockerfile Generator
Generate Dockerfiles for Node, Python, Next.js
E.164 Phone Formatter
Format phone numbers to E.164 (+966, +971…)
EditorConfig Generator
Download .editorconfig template
Email MX Checker
Check domain MX records for email delivery
Email Validator
Syntax check + optional MX lookup
Event Schema Generator
Event structured data markup
Fake Data / Mock Generator
JSON mock users and products for tests
Fapiao XML Parser
Free online Fapiao XML Parser — fast, private browser tool on Fneno.com.
FAQ Schema Generator
Build FAQPage JSON-LD for rich results
Git Commit Message Generator
Conventional Commits format builder
GitHub README Generator
README.md with badges & sections
GraphQL Formatter
Beautify GraphQL queries and mutations
HMAC SHA-256 Generator
Generate HMAC signatures for webhooks and APIs
HowTo Schema Generator
HowTo structured data with steps & supplies
Hreflang Tag Generator
Generate hreflang alternate links
htaccess Security Headers
Apache security headers snippet
HTML Email Signature
Professional email signature HTML block
HTML Entity Encoder / Decoder
Encode and decode HTML entities safely
HTML Formatter
Format and minify HTML markup in the browser
HTML Meta Tags Generator
Generate full SEO meta, OG, and Twitter tags
HTML Minifier
Compress HTML markup
HTTP Status Code Reference
Quick lookup: what every HTTP status code means (200, 404, 500…)
IBAN Validator & Formatter
Validate GCC and international IBANs
INI to JSON Converter
Parse INI config files to JSON
IP Range to CIDR
Convert IP ranges to CIDR blocks
ISBN Validator
Validate ISBN-10 and ISBN-13 check digits
JavaScript Minifier & Beautifier
Minify or pretty-print JS in browser
Job Posting Schema
Google Jobs JSON-LD markup
JSON Formatter Chinese Ui
Free online JSON Formatter Chinese Ui — fast, private browser tool on Fneno.com.
JSON to CSV Converter
Convert JSON array of objects to CSV
JSON to TypeScript
Generate TS interfaces from JSON
JSONPath Extractor
Query JSON with path expressions
JWK to PEM Converter
Convert RSA/EC JWK to PEM public key
JWKS JSON Validator
Validate JWK Set JSON for OIDC providers
JWT Generator (HS256)
Create signed JWT tokens with your secret
Local Business Schema
LocalBusiness JSON-LD for Maps & local SEO
Markdown Table Generator
Build aligned Markdown tables visually
Markdown to HTML Converter
Convert Markdown to clean HTML instantly
Markdown to HTML Converter
Convert Markdown to clean HTML
Markdown To Wechat Html
Free online Markdown To Wechat Html — fast, private browser tool on Fneno.com.
Medical WebPage Schema
Health content MedicalWebPage markup
Nginx Config Generator
Reverse proxy & SSL server blocks
Nginx Security Headers
Nginx add_header security snippet
OAuth2 PKCE Generator
code_verifier, code_challenge & auth URL
Offer Price Schema
Product Offer / price JSON-LD
Open Graph Preview
Preview how links look on social networks
OpenAPI Stub Generator
Build OpenAPI 3 YAML stubs for REST APIs
Organization Schema
Organization JSON-LD for knowledge panel
Password Strength Checker
Score passwords and get security tips
PEM Certificate Parser
Decode X.509 cert details
Person Schema Generator
Author / profile Person JSON-LD
Product Schema Generator
Product JSON-LD for rich results
PWA Manifest Generator
Progressive Web App manifest.json builder
QAPage Schema Generator
FAQ rich results QAPage JSON-LD
Recipe Schema Generator
Recipe rich results JSON-LD
Regex Pattern Library
Common regex patterns with live test
Review Schema Generator
Review & aggregateRating markup
robots.txt Generator
Build a valid robots.txt for search crawlers
RSA Key Pair Generator
2048/4096 RSA PEM keys in browser
Saudi National ID Validator
Validate Saudi ID / Iqama number checksum
Schema.org JSON-LD Generator
Create FAQ, Product, Organization structured data
SemVer Compare Tool
Compare semantic version numbers
SemVer Version Calculator
Bump major, minor, or patch versions
SEO Readiness Checker & Certificate
Score title, meta, headings, and content depth — get SEO readiness certificate
SERP Title Pixel Checker
Check if title fits Google SERP width
Software Application Schema
App / SaaS JSON-LD markup
Speakable Schema Generator
Voice assistant speakable markup
SQL CREATE TABLE Generator
Build SQL table DDL from columns
SQL Formatter
Beautify and indent SQL queries for readability
SRI Hash Generator
Subresource Integrity sha256/sha384 hashes
Subnet Calculator
Calculate CIDR, netmask, and host ranges
SVG Optimizer
Clean & compress SVG code
SWIFT / BIC Validator
Validate bank SWIFT/BIC codes
TOML to JSON Converter
Convert TOML config to JSON
Tourist Trip Schema
Travel / TouristTrip structured data
TXT DNS Lookup
Query TXT records (SPF, DKIM, verify)
Unix Timestamp Converter
Convert epoch seconds/milliseconds to dates and back
UUID Generator
Generate RFC-compliant UUID v4 identifiers instantly
Video Schema Generator
VideoObject JSON-LD for YouTube embeds
WCAG Color Contrast Checker
Check AA/AAA contrast for accessibility
Webhook Signature Verifier
Verify HMAC signatures (Stripe, GitHub, generic)
Webhook Tester
Send test HTTP requests to your URL
WebSite Schema Generator
Site search box structured data
Website Screenshot Tool
Enter a URL and capture a screenshot of the page
Website SEO Audit & Certificate
Paste any website URL — 13-point SEO audit + official certificate with your link and every finding
WhatsApp Link Generator
Generate click-to-chat WhatsApp links with pre-filled message
WiFi QR Code Generator
Scan-to-connect WiFi QR string
XML Formatter
Format, validate, and minify XML documents
XML Sitemap Generator
Create XML sitemaps for better search indexing
XPath HTML Tester
Run XPath on HTML/XML snippets
YAML ↔ JSON Converter
Convert between YAML and JSON both ways
Binary / Hex Converter
Convert between Binary, Decimal, Hex and Octal
Diff Checker
Compare two texts and highlight differences
JSON Formatter
Format, validate and beautify JSON instantly
CSS Gradient Generator
Generate beautiful CSS gradients visually
IP Address Lookup
Find location, ISP and details of any IP address
Base64 Encoder / Decoder
Encode and decode Base64 strings instantly
Color Picker & Converter
Pick colors and convert between HEX, RGB and HSL
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-512 hashes
JWT Decoder
Decode and inspect JWT tokens instantly
Morse Code Translator
Translate text to Morse code and back with audio
Regex Tester
Test regular expressions with live match highlighting
Roman Numeral Converter
Convert between Roman numerals and Arabic numbers
URL Encoder / Decoder
Encode and decode URL strings instantly
About this collection
❓ Frequently Asked Questions
Every tool listed below in the developer category on Fneno.
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