Atbash Cipher – Reverse Alphabet Encryption
Apply the ancient Atbash cipher (A→Z, B→Y) to any text. Since it's self‑inverse, encoding and decoding use the same function. Fun for code puzzles.
UD5 Toolkit
Protect your email address from spam bots and scrapers. Generate obfuscated code that displays correctly for humans but confuses automated harvesters.
Select a method above to see what the raw HTML looks like to an email harvester. Protected code makes it much harder for bots to extract your address.
@ becomes @ and . becomes .. Browsers render these entities as the original characters, but many bots scan raw source code and miss encoded addresses. It's one of the oldest and most reliable obfuscation techniques.
Apply the ancient Atbash cipher (A→Z, B→Y) to any text. Since it's self‑inverse, encoding and decoding use the same function. Fun for code puzzles.
Validate the syntax of an SPF record, check for the 10‑lookup limit, and flatten nested includes. Improve email deliverability by fixing SPF errors.
Type your email subject line and see how it will appear on mobile and desktop inboxes. Checks character limits and flags spammy words for better open rates.
Quickly compute click-through rate from impressions and clicks. Use it to measure ad performance, email campaign effectiveness, or organic search CTR.
Encrypt or decrypt text using the classical 5x5 Polybius square. Excludes J or merges I/J.
Create colorful, bulletproof HTML buttons for email. Uses VML for Outlook, graceful fallback for others.
Encode or decode data to/from Base58 (Bitcoin alphabet). Useful for cryptocurrency address generation testing. Fully local, no data sent.
Create a polished HTML email signature with your photo, links, and company details. Live preview and copy HTML to clipboard. Works with Gmail, Outlook, Apple Mail.
Encode or decode a string for use in a URL query parameter. See the raw and encoded versions. Dev tool.
Paste your email subject and body. The tool highlights common spam trigger words and gives a risk score. Improve inbox placement.
Write in Markdown and get clean, inline‑styled HTML suitable for emails. Pre‑designed templates included. Local conversion.
Paste raw email headers and see authentication results (SPF, DKIM, DMARC) in a readable table. Find spoofing attempts.
Encode latitude/longitude into a geohash string and decode a geohash back to coordinates with precision info. Local algorithm.
Convert integers into short, unique, YouTube‑style IDs (hashids) and decode them back. Customize salt and minimum length.
Generate a BIMI record to display your verified brand logo in email clients. Includes SVG logo URL and VMC certificate path.
Create a DMARC policy record with percentage, reporting addresses, and alignment mode. Validate and copy the final DNS TXT.
Generate a DKIM DNS record from a public key and selector. Check syntax. Improve your domain’s email deliverability.
Build a valid SPF TXT record by selecting mail servers, IPv4/IPv6 ranges, and includes. Validate syntax and get ready‑to‑publish output.
Build a complex mailto: link with to, cc, bcc, subject, and body. Get the HTML anchor tag. Local.
Encode any file into a Base64 string that you can copy, or decode a Base64 string back to a downloadable file. Pure frontend.
Convert your text into a string of emojis using a simple substitution cipher. Share secret messages that look fun. Decode them with the same tool. All local.
Instantly convert plain text into HTML‑safe escaped characters for secure display in web pages. Prevent cross‑site scripting. All processing local.
Enter a first name and last name, plus a domain, to generate common email address patterns. For finding contacts.
Paste your email body and subject, and get a spam score based on common trigger words and patterns. Improve your cold outreach.
Preview the Gravatar image associated with any email address. Generate the correct Gravatar URL. Handy for avatar debugging.
Paste email headers or body text to quickly spot phishing signs, suspicious domains, and obfuscated links. Educational and private.
Escape HTML special characters to prevent XSS attacks, or unescape HTML entities back to original text. Essential for web developers. Runs locally.
Obfuscate strings using simple techniques to prevent casual reading. Useful for hiding spoilers or email addresses from bots. Decode with the same tool.
Transform any image into a Base64 data URI for embedding directly into HTML, CSS, or JSON. Drag and drop support. Entirely browser-side conversion.