Looking Glass (BGP)

Send HyperText Transfer Protocol (HTTP) requests with custom method, headers, body, and authentication — inspect the full response.

Load a Uniform Resource Locator (URL) in headless Chromium and stream every fetched resource with size and timing.

The simplest possible check: fetch the page, confirm it returns 2xx.

Test any Uniform Resource Locator (URL) for Cross-Origin Resource Sharing (CORS) with a custom method, headers, and body — see exactly why a browser would allow or block the request.

Crawl a website and find broken internal links — renders JavaScript (JS) pages with a headless browser.

Check an IPv4 address against 49 major Domain Name System (DNS) blacklists (Spamhaus, SORBS, Barracuda, SpamCop, etc.).

Continuous traceroute with per-hop loss and Round-Trip Time (RTT) statistics.

Trace the path packets take to a destination host, hop by hop.

Ping many hosts in parallel and report which are alive.

Send Internet Control Message Protocol (ICMP) echo requests and report round-trip time (RTT) and packet loss.

Resolve a domain or Internet Protocol (IP) address to its city, country, Autonomous System Number (ASN)/org, and coordinates — with a map.

Convert IPv4 to/from IPv4-mapped IPv6 (::ffff:a.b.c.d).

Look up a Media Access Control (MAC) address's first 3 octets in the IEEE Organizationally Unique Identifier (OUI) vendor database (curated subset).

One-click domain scorecard — Blacklist, Mail Server, Web Server, and Domain Name System (DNS) checks graded Errors / Warnings / Passed, MXToolbox-style.

Consolidated Mail Exchange (MX), Sender Policy Framework (SPF), Domain-based Message Authentication, Reporting & Conformance (DMARC), and DomainKeys Identified Mail (DKIM)-selector lookup for an email domain.

Look up and validate a domain's Sender Policy Framework (SPF) Text (TXT) record.

Resolve a domain's Mail Exchange (MX) hosts to Internet Protocol (IP) addresses and check each against 49 IP blacklists plus the domain itself against 9 domain blacklists.

Connect to a Simple Mail Transfer Protocol (SMTP) server, capture its banner + EHLO capabilities, and test STARTTLS.

Check Transmission Control Protocol (TCP) port reachability; optionally send a payload and read the reply.

Inspect a server's Transport Layer Security (TLS) handshake: version, cipher, Application-Layer Protocol Negotiation (ALPN), full cert chain.

Probe a list of hostnames (max 16) for HyperText Transfer Protocol (HTTP) and HyperText Transfer Protocol Secure (HTTPS) availability.

Send N HyperText Transfer Protocol (HTTP) HEAD requests to a Uniform Resource Locator (URL) and report min/median/mean/max/stddev latency. From this server's vantage.

Discover the path Maximum Transmission Unit (MTU) to a host by sending increasingly large pings with the Don't Fragment (DF) bit set (binary search).

Break a Classless Inter-Domain Routing (CIDR) block into network, broadcast, mask, wildcard, and usable host range.

Verbose subnet calculator with address classification flags.

Generate router prefix-list and AS-path filters from IRR data.

Probe which Transport Layer Security (TLS) protocol versions a server accepts and show the cipher each negotiates.

Full chain validation, Online Certificate Status Protocol (OCSP) stapling, Signed Certificate Timestamp (SCT) count, and per-Transport Layer Security (TLS)-version cipher matrix.

Days remaining before a server's Transport Layer Security (TLS) certificate (and its full chain) expires.

Search Certificate Transparency logs for every Secure Sockets Layer (SSL) certificate ever issued to a domain — reveals subdomains, issuers, and historical issuance.

Query a public Network Time Protocol (NTP) server: stratum, offset, round-trip, ref-id, root delay/dispersion. Does not change the system clock.

Fetch a server's SSH version banner and host public keys (Ed25519, ECDSA, RSA) with fingerprints. No authentication.

Negotiate HTTP/2 via Application-Layer Protocol Negotiation (ALPN) and decode the server's SETTINGS frame (window size, max streams, etc.).

Send a WebSocket Upgrade handshake and verify the Sec-WebSocket-Accept response, subprotocols, and extensions.

Benchmark HTTP/2 server performance — measure requests per second, latency distribution, and concurrent stream throughput under sustained load.

Convert UTF-8 text to a hex string, or parse a hex string back to text (separators :/.- ignored).

Convert UTF-8 text to 8-bit binary, or parse a binary string back to text.

Convert text between common casings: UPPER, lower, Title, snake_case, kebab-case, camelCase.

Convert a number between decimal, binary, octal, and hexadecimal representations.

Convert between Unix epoch seconds and International Organization for Standardization (ISO)/Request for Comments (RFC) datetime formats (Coordinated Universal Time (UTC)).

Convert between dotted IPv4 notation, 32-bit decimal, hex, and dotted binary.

Decode a JSON Web Token (JWT) into its header and payload (no signature verification — that needs the signing key).

Compute the cryptographic hash of UTF-8 text using MD5, SHA-1, SHA-256, SHA-384, or SHA-512.

Compute a Hash-based Message Authentication Code (HMAC) of a message using a shared key and a chosen hash algorithm.

Days remaining before a domain's registration expires.

Days remaining before a domain's Resource Record Signatures (RRSIGs) — the cryptographic signatures used by Domain Name System Security Extensions (DNSSEC) — expire.