Every developer tool you reach for, in one place.
API testing, JSON tools, JWT decoder, regex, DNS, SSL and more. With your projects saved, results shareable, and your team always one invite away.
Fast
Most tools run in your browser. No upload, no server roundtrip.
Private
Your API keys, secrets, JWT — never leave your device for client-side tools.
Shareable
Save runs to projects. Share a link with your team in one click.
Always free
No tier locks. No 14-day trials. Genuinely free, forever.
76 tools live today
More launching every week. Browse, try, save to your workspace.
API & Network
Data Tools
Security & Auth
DNS & Email Auth
Developer Utilities
SEO
Schema JSON-LD Generator
Article, Product, FAQ, LocalBusiness, Org, Breadcrumb, Event, Review, Recipe
Meta Tag Analyzer
Audit title, description, canonical, robots, OG for any URL
Google SERP Snippet Preview
Pixel-accurate title + description truncation preview
robots.txt Tester
Is my URL allowed by robots.txt? Which rule matched?
robots.txt Generator
Build a robots.txt from rules with CMS presets
XML Sitemap Validator
Validate sitemap.xml structure, list URLs, report errors
XML Sitemap Generator
URL list → sitemap.xml with priority + changefreq
Redirect Chain Checker
Trace 301/302 hops, catch loops and soft-404s
OG / Twitter Card Validator
Extract OG + Twitter tags, preview FB / LinkedIn / X shares
Hreflang Generator
Locale + URL matrix → hreflang tags with reciprocity guidance
Keyword Density Analyzer
1/2/3-gram frequency + stopwords; paste text or URL
Keyword Cannibalization Checker
Find pages competing for the same query (TF-IDF cosine similarity)
Heading Structure Checker
H1-H6 outline; flag missing H1, multiple H1s, skipped levels
Image Alt Auditor
Find images with missing or empty alt text
Canonical Tag Checker
Verify canonical URL presence, uniqueness, self-reference
Hreflang Checker
Validate hreflang — reciprocity, x-default, self-reference
Word Count & Content Ratio
Word count, text-to-HTML ratio, thin-content verdict
Structured Data Detector
Find JSON-LD, Microdata, RDFa on any page
Link Extractor
List all internal and outbound links with anchor + rel
Broken Link Checker
Check the first 100 outbound links for 4xx/5xx/errors
HTTP Headers Checker
Full HTTP response headers and status for any URL
Canonicalization Checker
Test all 4 variants (www/non-www x http/https) canonicalise to one
Security & Cache Headers
HSTS, CSP, X-Frame, cache-control — full security header audit
Meta Robots / X-Robots Checker
Extract meta robots directives + HTTP X-Robots-Tag header
Mixed Content Checker
Find http:// resources loaded on https:// pages
Meta Tag Generator
Generate title, description, canonical, OG, Twitter tags
Keyword Combiner
Permute 3 seed lists into every keyword combination
Text / Word / Char Counter
Character, word, sentence, paragraph counts + reading time
URL Slugifier
Convert any string to URL-safe slug (kebab, snake, camel, dot)
UTM Campaign Builder
Build tracked URLs for Google Analytics utm_source, medium, campaign
Readability Score
Flesch, Flesch-Kincaid, Gunning Fog, SMOG, ARI, Coleman-Liau
PageSpeed & Core Web Vitals
Google Lighthouse: LCP, FCP, TBT, CLS, plus perf/SEO/a11y scores
Mobile-Friendly Check
Viewport, tap targets, font size, content width via Lighthouse
Safe Browsing Check
Google Safe Browsing v4 — flagged for malware, phishing, unwanted?
GEO — AI Answer Engines
llms.txt Generator
Build a spec-valid llms.txt for AI crawlers
llms.txt Checker
Fetch and validate a site's llms.txt + llms-full.txt
AI Bot Access Checker
GPTBot, ClaudeBot, Google-Extended, PerplexityBot — allowed or blocked?
Answerability Score
Score how well your page answers AI queries — with prioritized fixes
GEO Readiness Checklist
30+ item self-assessment across strategy, content, technical, measurement
Cite-Worthiness Score
How quotable is your page for AI answers? 14 heuristic checks
Citable Sources Scanner
Flag claims that need citations
AI-Answer Formatter
Restructure content into TL;DR + Q&A + bullets for AI ingestion
llms.txt Auto-draft from Sitemap
Fetch your sitemap and generate a ready-to-edit llms.txt
llms-full.txt Builder
Fetch up to 25 pages, convert each to Markdown, assemble llms-full.txt
AI Meta / X-Robots Generator
Control AI training — noai, noimageai, max-snippet, noarchive
Content Freshness Checker
Extract publication dates and score how stale the content is
TL;DR Helper
Compress any content into an AI-quotable summary of N words
URL to Clean Markdown
Fetch any page, convert to clean Markdown (for RAG or llms-full.txt)
RAG Chunk Previewer
See how content splits into retrieval chunks (tokens/paragraphs/headings)
Entity / Key-Topic Extractor
Find named entities (people, orgs, places, products) and key topics