Small utilities with explicit privacy boundaries
Privacy, Domain & Developer Tools
A practical toolbox for email and DNS diagnostics, secure password generation, and local developer data tasks. Browser-only tools keep your input on your device.
Email & domain diagnostics
Inspect DNS mail routing, sender authentication, raw headers, and disposable-domain signals.
MX Lookup
Check the mail exchange records for any domain and see which servers receive its email.
Open toolSPF Checker
Find and review the SPF TXT record that tells receivers which servers may send mail for a domain.
Open toolDMARC Checker
Check a domain's DMARC TXT record and review its policy, reporting, and alignment settings.
Open toolDKIM Checker
Lookup a DKIM selector and domain to confirm whether the public signing key is published in DNS.
Open toolHeader Analyzer
Paste raw email headers to inspect routing hops, authentication results, message IDs, and sender details locally in your browser.
Open toolDisposable Domain Checker
Check whether a domain or email address appears on the public disposable-email blocklist, and verify with a live DNS lookup whether it can actually receive mail.
Open toolWeb privacy
Generate strong random passwords without sending the result to a server. Processing happens locally in your browser.
Password Generator
Generate strong random passwords with adjustable length, character sets, and batch size using your browser's cryptographic random source.
Open toolLocal data workbench
Format JSON, generate UUIDs, and hash text or files without uploading their contents to TmpKit.
JSON Formatter
Validate, format, minify, alphabetically sort, and summarize JSON entirely inside your browser.
Open toolUUID Generator
Generate one or many standards-shaped UUID v4 random identifiers or time-ordered UUID v7 identifiers locally.
Open toolHash Generator
Generate SHA-256, SHA-384, or SHA-512 hashes for local text or files and compare the result with a published checksum.
Open tool