Every web tool
you keep Googling for. One tab.
SEO scores, DNS lookups, email deliverability, SERP previews, security headers, sitemap validators — without bouncing between fifteen tabs. Free for anonymous use with sensible per-IP rate limits. An account unlocks history, batch runs and the API.
55 tools
Free in your browser
No login
For the basics
No ads
Or trackers, ever
55 tools. Seven categories. One page.
Search, filter, click. The greyed-out ones are landing on a rolling basis.
Lighthouse score
Perf · SEO · A11y · Best Practices for any URL.
SERP preview
Google preview: title, description, URL — with length warnings.
Sitemap validator
Fetch sitemap.xml or a sitemap index, validate the XML, sample URLs with lastmod / priority.
Robots.txt analyzer
Parse a domain's robots.txt and simulate a crawler per User-Agent against a given path.
Meta tag inspector
Fetch a URL and list every meta + link tag grouped by namespace: standard, OpenGraph, Twitter, canonical, alternates.
Schema.org validator
JSON-LD and microdata.
COMING SOON
Broken link checker
Crawl 1 level, list all 404s. Batch up to 10 sites.
COMING SOON
OG card preview
See how a URL renders as a Twitter card, LinkedIn share and Slack unfurl — with warnings for missing or oversized fields.
Email verifier
Syntax + MX records + disposable-provider list. SMTP probe in a follow-up.
SPF / DKIM / DMARC
Pull and parse a domain's email-authentication TXT records. Score + warnings.
Blacklist checker
Query an IP or domain against 30+ DNSBLs (Spamhaus, SpamCop, Barracuda…) in parallel.
Spam score
Heuristic SpamAssassin-style scoring of a draft. Runs entirely in your browser.
Inbox placement
Gmail · Outlook · Yahoo deliverability.
COMING SOON
DNS lookup
A · AAAA · MX · TXT · NS · SOA · SRV in one shot, against Cloudflare resolvers.
DNS propagation
30 resolvers around the world.
COMING SOON
WHOIS + expiry
Domain age, registrar, expiration. Email alerts before expiry.
COMING SOON
SSL / TLS analyzer
Version, cipher, chain, score.
COMING SOON
CT log search
Search Certificate Transparency logs (crt.sh) for every cert issued for a domain — find forgotten subdomains.
Reverse DNS
IP (v4 or v6) → PTR hostname(s).
Load test
RPS + duration → p50/p95/p99 from 3 regions.
COMING SOON
TTFB tester
Latency from 8 regions.
COMING SOON
Webhook tester
Temporary URL that logs hits in real time.
COMING SOON
HTTP header inspector
Full response headers, redirect chain, and request timing for any URL.
Network waterfall
WebPageTest-style trace.
COMING SOON
Security headers
CSP · HSTS · X-Frame · Referrer-Policy · Permissions-Policy · COOP · CORP — graded A+ to F.
CORS tester
Send a preflight + actual request from a given Origin and see exactly which CORS headers the server returns.
Mixed content scanner
Scan an HTTPS page for HTTP src / href / action resources that modern browsers block.
JWT decoder
Header · payload · signature. Decoded entirely in your browser.
HMAC generator
HMAC-SHA1/256/384/512 with your key. Runs in your browser via Web Crypto.
JWT signature verify
Verify a JWT against a public key (PEM or JWK) — entirely in your browser.
File hash
Drop a file, get its SHA-256 / SHA-1 / MD5. The file never leaves your browser.
Password generator
Strong passwords with entropy meter. Generated locally via crypto.getRandomValues.
TLS expiry monitor
Scheduled checks, email + Slack alerts 30 days before expiry.
COMING SOON
Hash generator
MD5, SHA-1, SHA-256, SHA-384, SHA-512. Computed in your browser — input never leaves the page.
JSON formatter
Format, minify, validate, sort keys. Stays in your browser.
Regex tester
Pattern + flags + test string + capture groups.
Cron parser
0 */6 * * * → human-readable + next 5 runs.
URL / Base64 / hex
Encode and decode URL, Base64, Base64-URL and hex. All conversions run locally.
Timestamp converter
Unix epoch ↔ ISO 8601 ↔ human-readable, in any timezone.
Color converter
HEX ↔ RGB ↔ HSL ↔ OKLCH with a live preview.
UUID / ULID gen
v4, v7, ULID, NanoID.
Case converter
camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE, Title Case, sentence case.
Slugify
Turn any string into a clean URL slug — Unicode normalised, diacritics stripped.
Number base converter
Convert between binary, octal, decimal and hex with arbitrary-precision integers.
Card / IBAN validator
Luhn check for credit cards (with issuer detection) and mod-97 check for IBAN.
Text stats
Characters, words, lines, sentences, reading time and approximate LLM token count.
Diff tool
Compare two blobs of text side-by-side or as a unified diff. Whitespace and case toggles.
HTTP status lookup
Search the full list of HTTP status codes — number, reason phrase, category and meaning.
User-Agent parser
Break down a User-Agent string into browser, engine, OS, device and bot heuristics.
IP / CIDR calculator
IPv4 and IPv6 CIDR math: network, broadcast, first / last host, mask, host count, classification.
Punycode converter
Convert internationalised domain names (IDN) to ASCII Punycode and back.
ASCII / Unicode inspector
Inspect every codepoint of a string: UTF-8 bytes, UTF-16 units, HTML entities, CSS escape, Unicode block.
Meta description gen
3 SEO-optimised proposals.
Powered by FerrFleet
Alt-text generator
Upload image → accessible alt text.
Powered by FerrFleet
Schema.org builder
Form → valid JSON-LD.
Powered by FerrFleet
A response to all of that.
Marketers, SEO consultants, sysadmins, support engineers, devs — anyone who ships, audits, or troubleshoots websites ends up with thirty bookmarks for tools they use twice a year. Half are dead, half are full of ads, half want your email before they run. FerrLens is the same tools, in one place, free for the obvious stuff, an account for the rest.
Same tools. Curl-friendly.
Every public tool has a JSON endpoint under api.ferrlens.com.
Anonymous IPs get a low rate limit — enough to try, not enough to scrape. An account
with an API token unlocks a real quota and batch endpoints.
# Anonymous — free, IP rate-limited
curl -X POST https://api.ferrlens.com/v1/seo/check \
-H 'content-type: application/json' \
-d '{"url":"https://example.com"}'
# With a token — higher quota + batch
curl -X POST https://api.ferrlens.com/v1/seo/check \
-H 'authorization: Bearer ferrlens_xxx' \
-H 'content-type: application/json' \
-d '{"url":"https://example.com"}'
A toolbox
that respects your attention.
Free anonymous tier. Bookmark it. Send it to your team. We will not email you.
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