Digizap — Your digital pocket knife
Website
Website scan — Scan an external website for performance, SEO, accessibility, security and privacy — including every TLS version and every candidate cipher at the final address. The report and the grade are built in your browser.HTTP headers — See the request and response headers of any public URL, including the redirect chain and a shortfall list of missing security headers.Certificate check — When does the certificate expire, who issued it, does it cover this host and how strong is the key? Straight from the TLS handshake.Link preview — What Google, LinkedIn or WhatsApp takes from the head of your page: title, description, og:image, canonical and what is missing. The HTML is read in your browser.Linked data — The JSON-LD your page already carries, read as a search engine finds it: blocks, nodes with @type, properties — and the JSON that does not parse. Built on the same HTML reading as Link preview.Favicon and manifest — Favicon, apple-touch-icon and manifest: declared in the HTML, fetched by our server, and judged on what a phone actually asks for.Domain hygiene — Redirect chain, bare against www, IPv4 and IPv6, nameservers, MX, SPF and CAA: how your domain presents itself outside, and where it rattles.robots & sitemap — Read what your site forbids and allows crawlers, rule by rule, cross-check your sitemap, and see what each of eleven named AI crawlers may do at / — llms.txt included.Index check — Whether head and header admit a crawler: meta robots and X-Robots-Tag directive by directive, every canonical block and the address they state, what stays out of the text and what is missing. Read in your browser.HTTP status — Every HTTP status code you meet in the wild, in plain language: what it means, why you see it and what you do with it.Link check — Read every link of a page and then measure your own links one by one: which find nothing, which detour, which point at http.Feed finder — See which feeds a page advertises and which ones really stand: rel=alternate declarations measured on status and content type, five standard paths probed separately, and a URL that is itself a feed parsed on the spot.Redirect chain — Follow every redirect of one address hop by hop: which status code, where http becomes https, whether bare and www end on the same address, and how long the chain is.security.txt — Check a site’s security.txt — standard path and legacy path, fields, expires and contact — and build a valid, ready-to-use file of your own.CSP analyzer — Read every Content-Security-Policy of one address — enforced and report-only separately, directive by directive — with the measured shortfalls: unsafe-inline without a nonce or hash, wildcard sources and open framing.
Email
Email scan — Check whether an address can really receive mail and whether a message passed its SPF, DKIM and DMARC checks. Nothing is sent.SMTP status — Every SMTP reply code from RFC 5321 and every enhanced status code from RFC 3463, in plain language. Plus a reader that explains a bounce message without sending anything.Mail security — The whole mail layer of one domain in view: MX, SPF, DMARC, DKIM keys and their bits, BIMI, MTA-STS, TLS-RPT and DANE, with a grade.MTA-STS and DANE — The TLS policy of your mail closed off in view: the MTA-STS policy laid beside your MX and your TLSA pins beside the certificate your mail server presents live, with a grade.Blacklist check — Does your mail server stand on Barracuda Central, SpamCop, Abuse CBL, PSBL or SpamRATS? Every public IPv4 address of your mail against five zones, with the RFC 5782 self-test up front and each zone's policy and removal path in the report, with a grade.DMARC reports — Read a DMARC aggregate report (RFC 7489) in your own browser: reporter, policy, dispositions, authentication combinations and the sources where SPF and DKIM failed together.SPF check — Work out whether an IP address may send mail as a domain: the whole include chain, the lookup limit of RFC 7208 and the same answer a receiver would give.DKIM check — Paste the source text of a message and have the signature verified: body hash, header set, key length and whether the signature really belongs to this message. The message stays in your browser.Mail ports — Check whether SMTP, SMTPS, Submission, IMAP and POP3 really are open on your mail server — with the greeting the server itself sends and the time per port.Mail header analyzer — Paste the raw headers of a real message and put the Received chain and the Authentication results on one timeline: hop by hop, with timestamps, time differences and each receiver’s verdict.Unsubscribe — Paste the headers of a newsletter or mailing and read its unsubscribe links: List-Unsubscribe entry by entry, the one-click rule on its letters, and every link name against the DKIM domain. The mail never leaves your browser.
Network
DNS lookup — All records of a domain in one overview: A, AAAA, NS, MX, TXT, CNAME, SOA, CAA and SRV — including SPF and DMARC checks.DNS compare — After a DNS change: ask the same record from our server at four public resolvers and from your own browser at Google, Cloudflare and Quad9, and see per resolver whether the new value is already there, where the old answer still stands and which TTL covers it.Reverse DNS — Whether a machine’s name and address confirm each other: forward to addresses, PTR back, confirmation forward again — walk by walk per address, read in your browser.HTTP/2 and HTTP/3 — Measure in three samples on your own connection whether a site speaks HTTP/3, HTTP/2 or HTTP/1.1 — where your browser reveals the protocol — with the ALPN handshake from our server as a second direction of looking.DNSSEC check — Read a domain’s keys and signatures: DNSKEY, the parent DS, recomputed digests, and whether the signatures are still within their validity period.RDAP lookup — Ask the registry IANA points at who registered your domain, when it expires, which status it carries, and which nameservers and DS keys hang off it.Who am I? — Show the public address your browser makes this request with and ask the registry belonging to that address what it reports: network name, range, country and organization.Reachability — Measures DNS, TCP, TLS, TTFB and total response time across several samples. See whether a site is stable or actively coming apart.Port check — Tell whether SSH, HTTP, HTTPS and other services are really reachable on their port — with what the service itself says, the time per port, and a firewall's silence kept separate.SSL test — OCSP stapling, timestamps (SCTs), certificate choice per name (SNI), session resumption, the chain the server delivers, every TLS version probed separately and every candidate cipher per version — straight from the handshake. The grade is a weighted average of all those measured checks; a probe that could not be measured carries no weight.CIDR calculator — Draw out address space: mask, broadcast, usable hosts, subnet division and supernet merging. All local, no address leaves your browser.IP planner — Divide a base network over a list of wishes, with the gaps that remain, colliding blocks and an address check. The computation stays in your browser.IPv6 workbench — Write an IPv6 address the way RFC 5952 recommends, recognise address types, draw out networks and /64s and get the ip6.arpa name with it. Arithmetic in your browser, 128 bits wide.
Data
Crypto & hashing — Six tools: hashing, making an HMAC, checking an HMAC, encrypting with a passphrase, opening a block again and randomness from the browser CSPRNG.Hash and CRC — Drop a file or paste text and see CRC32 and SHA-1, SHA-256 and SHA-512 — computed in your browser, with a field to test an expected checksum against.Converters — Convert JSON, base64, URL, HTML, JWT, CSV and names, make times and weights readable. All in this browser, live.Regex tester — Test patterns with live marking, group readout and a replacement example — including a library of Dutch patterns (postcode, IBAN, KvK, phone).Text diff — Compare two texts line by line, with marking down to word level and a unified patch to copy. Computes in your browser.Cron reader — A cron expression in words: every field explained, the next run moments, and where the expression stumbles (day and weekday).Cron builder — Turn plain words back into a cron expression: "every day at 6:05", "on weekdays at 9:00", "every 15 minutes" — deterministic, limited to the forms the tool knows, checked by the cron reader.Color contrast — WCAG ratio between two colours, with level per use (text, large text, AAA, buttons) and a colour that does make it. Computes in your browser.Report comparison — Compare two saved reports from the same tool: grade, score, findings and metrics, matched by id.PGP reader — Paste an armored OpenPGP key block and read its fingerprint, key id, algorithm, curve, subkeys and packet boundaries — all in your own browser, with the non-claims attached.Feed reader — Paste the body of an RSS, Atom or JSON Feed and read it on the spot in your own browser: shape, entries block by block, titles, dates and addresses — the counts come from the document itself.UUID and ULID — Paste uuids, ulids and objectids and read their version, variant, time and random fields bit by bit; build one yourself with your browser CSPRNG, with the non-claims attached.
Your digital pocket knife: 51 free IT tools across 4 subjects — website, mail, network and data. Measurements run in your own browser, without external APIs.
API documentation — 26 public measurement endpoints, machine-readable at /openapi.json . Knowledge base — 26 articles about website, mail, network and data, each with the instrument you measure with