elitesystem.net

Free tools

Public, no-signup utilities for email, Bitcoin, Nostr, Lightning, and network research. Sensitive Bitcoin tools run locally whenever possible, and inputs are never retained.

Email

Inspect public mail-domain configuration without sending a message or connecting to SMTP.

Email domain health

Check MX routing, SPF dependencies and lookup budget, explicit DKIM selectors, current DMARC policy discovery, MTA-STS, and TLS reporting through the isolated DNS resolver.

Bitcoin

Address, transaction, PSBT, and key-derivation utilities. Every tool in this group runs entirely in your browser — no address, descriptor, seed, or PSBT is ever sent to the server.

Address inspector

Validate mainnet, testnet, signet, or regtest addresses and inspect their script type, scriptPubKey, and descriptor hint.

Fee planner

Compare transaction fees and calculate RBF or CPFP targets locally in your browser without sharing wallet data.

Raw transaction decoder

Decode transaction hex, inspect inputs and outputs, identify RBF signaling, and flag dust without broadcasting anything.

Transaction planner

Calculate fees, recipients, change, and dust from explicit UTXOs entirely in your browser.

PSBT inspector

Inspect PSBT inputs, outputs, UTXO metadata, signatures, fees, and completeness locally without signing or uploading the file.

Unsigned PSBT builder

Build a BIP174 PSBT from explicit UTXOs, recipients, change, fee rate, and size entirely in your browser.

Xpub address explorer

Derive BIP44, BIP49, BIP84, and BIP86 watch-only receive and change addresses with no blockchain lookup.

BIP39 wallet generator

Generate a mnemonic and BIP44, BIP49, BIP84, or BIP86 addresses entirely in your browser. Offline use is strongly recommended.

BIP39 recovery checker

Validate an existing mnemonic and derive BIP44, BIP49, BIP84, or BIP86 watch-only addresses locally without exposing seed material.

QR generator

Generate local QR images for addresses, BIP21 URIs, xpubs, descriptors, and small PSBT payloads.

Lightning

Utilities for the Lightning Network payment layer.

LNURL decoder

Decode any LNURL bech32 string, lightning address, or LNURL URL, then fetch and pretty-print the response: payRequest, withdrawRequest, login, channelRequest.

Nostr

Identity and key utilities for the Nostr protocol.

NIP-05 checker

Validate a name@domain Nostr identifier end-to-end: URL format, HTTPS, redirects, CORS headers, JSON shape, pubkey format, advertised relays. Real npub bech32 output.

Key generator

Generate a fresh Nostr keypair (priv/pub hex, nsec, npub, nprofile) entirely in your browser. Optional vanity-prefix search via Web Worker. Nothing is sent or stored.

Network

Registry and routing research. These run server-side, so they see what a registry or resolver really answers.

WHOIS & RDAP lookup

Look up a domain, IP address, or AS number against the authoritative registry — every RIR (ARIN, RIPE, APNIC, LACNIC, AFRINIC) and every TLD. Check availability, expiry, nameservers, network allocation, and BGP origin.

What is my IP address

See the address you are connecting from, its reverse DNS name, the autonomous system announcing it, and the network operator that holds the allocation — the quickest way to confirm a VPN is actually carrying your traffic. Also available as plain text for the shell: curl elitesystem.net/ip.

TLS certificate checker

Resolve A and AAAA addresses, then inspect certificate trust, hostname matching, supported TLS versions, cipher suite, ALPN, expiry, key strength, fingerprint, OCSP stapling, and the presented chain on port 443.

DNS record inspector

Query A, AAAA, CNAME, MX, NS, TXT, CAA, SOA, DS, DNSKEY, and PTR records with TTLs and recursive DNSSEC validation status.