Free marketing tools Data and developer
Utilities for working with event data and reports. Nothing you paste leaves the browser.
Timestamps, JSON, URL encoding, hashing and cron.
Timestamp converter
Convert Unix timestamps in seconds, milliseconds, microseconds or nanoseconds to dates in any time zone, and dates back to timestamps.
- Detects the unit from the digit count
- Paste a whole column to convert in bulk
- ISO 8601, seconds and milliseconds side by side
JSON formatter
Beautify, minify and validate JSON in the browser, with the exact line and column of any syntax error.
- Pretty-print with 2 or 4 spaces or tabs, or minify
- Points to the line and column that broke
- Optional key sorting, key count, depth and size
URL encoder and decoder
Percent-encode a parameter value or a whole URL, or decode %XX sequences back into readable text.
- encodeURIComponent and encodeURI modes
- Decode with or without + as a space
- Clear message when a % sequence is broken
Hash generator
MD5, SHA-1 and SHA-256 hashes of any text, with email normalization and line-by-line hashing for lists.
- Three algorithms at once, UTF-8
- Trim and lowercase before hashing
- Nothing leaves your browser
Cron expression generator
Explain any cron schedule in plain words and list its next run times in your time zone. 5-field crontab and 6-field Spring / Quartz.
- Plain-language description
- Next 5, 10 or 20 runs, DST-aware
- One-click common schedules
Chart maker
Paste a table from Excel, Google Sheets or CSV and get a clean pie, bar, line, funnel or Sankey chart. Export SVG or PNG.
- Five chart types, header row detected
- Colour-blind-safe palettes
- SVG, PNG and inline embed code
Screen resolution
See your screen resolution in CSS and physical pixels, device pixel ratio, viewport and aspect ratio, plus a table of current phones, tablets and Macs from official specs.
- CSS pixels, physical pixels and pixel ratio
- Viewport, available area and display features
- Device table sourced from manufacturer spec pages
JSON to CSV converter
Turn JSON or JSON Lines into a spreadsheet-ready CSV, or CSV back into JSON, with line-level error messages.
- Nested objects become dotted columns
- RFC 4180 quoting, auto-detected delimiter
- Optional BOM so Excel reads UTF-8
Diff checker
Compare two texts, robots.txt files or configs and see additions and deletions by line, word or character.
- Side-by-side or unified view
- Ignore whitespace and case
- Fast on 10,000+ lines, runs locally
Days between dates
Count the days, weeks and months between two dates, with or without the end date, plus business days after US federal or China public holidays.
- Include or exclude the end date
- US federal and China public holidays
- Weekday-aligned comparison periods
Date calculator
Add or subtract days, weeks, months or years, add business days around US or China holidays, and see the weekday, ISO week and day of the year.
- What date is 90 days from today
- Business days with observed holidays
- ISO week number and day of year
Base64 encoder and decoder
Decode Base64 to readable text or encode text to Base64 with proper UTF-8, and turn images or files into Data URIs.
- Standard, URL-safe and MIME options
- Image or file to Data URI
- Points to the exact bad character
UUID generator
Generate random v4 or time-ordered v7 UUIDs in bulk, in any format, and decode existing UUIDs to see their version and timestamp.
- v4 and v7 (RFC 9562), up to 1,000 at once
- Upper case, no hyphens, braces, JSON
- Decodes v1, v6 and v7 timestamps
JWT decoder
Decode a JSON Web Token into header and claims, see exp, iat and nbf as local times, and verify the signature with a secret or public key in your browser.
- Expiry shown in your time zone
- HS, RS, PS, ES and EdDSA verification
- PEM, certificate, JWK or JWKS keys
HTML entity encoder and decoder
Escape angle brackets, ampersands and quotes so code shows as text, or decode entities back into characters.
- All 2,231 WHATWG named references
- Flags double-escaping and missing semicolons
- Named, decimal or hex output
Unicode converter
Convert text to \u escapes and back, see UTF-8 bytes and code points, switch full-width and half-width, and strip invisible characters.
- \u, \u{}, U+, HTML and CSS escapes
- UTF-8 and UTF-16 for every character
- Finds zero-width and no-break spaces
JS, CSS and HTML minifier
Minify JavaScript, CSS or HTML in the browser and see the real size before and after gzip.
- JavaScript with local variable renaming
- Safe CSS and HTML whitespace and comment removal
- gzip size measured, not estimated
SQL, XML and YAML formatter
Pretty-print and validate SQL, XML and YAML in the browser, with errors pointed to the line and column.
- SQL in 9 dialects, plus TapCub SQL rules
- XML well-formedness checks like a real parser
- YAML values that change type are flagged
JSON to YAML converter
Convert JSON to YAML or YAML to JSON in the browser, with line-level errors and warnings for values that change type.
- Both directions, multi-document YAML included
- Strings like "no" and "2026-12-01" stay strings
- Anchors and merge keys resolved
Email validator
Check and clean a list of email addresses: syntax, typos, disposable domains, duplicates, and an optional MX lookup.
- Paste one address or 20,000
- Typos like gmial.com, disposable domains, duplicates
- MX check only when you click, domains only
Email header analyzer
Paste raw email headers to see every hop and its delay, SPF, DKIM and DMARC results, alignment and the fields that give a spoof away.
- Hop-by-hop delay from the Received chain
- SPF, DKIM, DMARC and alignment in one table
- Parsed in your browser, never uploaded
HEX to RGB color converter
Convert any color between HEX, RGB, HSL, HSV, CMYK and OKLCH, and check its WCAG contrast against a background.
- Paste any format, get all of them
- WCAG AA / AAA contrast with a fix
- Copy-ready CSS
Image compressor
Compress and resize JPG, PNG and WebP images in your browser, convert to WebP or AVIF, compare before and after, and download one by one or as a ZIP.
- Batch: drop up to 60 images
- Quality, max size or a target file size
- Strips EXIF and GPS, nothing uploaded
Favicon generator
Make a favicon from an image, text or an emoji: favicon.ico with 16, 32 and 48 px, Apple touch icon, 192 and 512 px manifest icons, site.webmanifest and the HTML tags.
- Real multi-size ICO with PNG inside
- Sizes from Google and Apple docs
- ZIP download, nothing uploaded
Color contrast checker
Check any text and background pair against WCAG 2.2 AA and AAA, get the nearest passing color, and preview a chat widget in your brand color.
- AA / AAA, large text and non-text 3:1
- Nearest passing text or background color
- Chat widget and button color preview
DNS lookup
Look up A, AAAA, CNAME, MX, TXT, NS, SOA, CAA, SRV and PTR records, and compare Cloudflare, Google and Alibaba Cloud resolvers.
- 10 record types plus reverse lookup
- Compare three public resolvers
- SPF, DMARC, DKIM and MX checkers
WHOIS lookup
Registrar, registration and expiry dates, status codes, name servers and DNSSEC for a domain, from the registry’s RDAP service.
- Registry and registrar RDAP
- Every status code explained
- Domain age and days to expiry
Questions about the tools
Still have a question?
Chat with the team behind TapCub — we usually reply within a few hours on business days.
Do I need a TapCub account to use them?
No. The tools are public pages. An account only matters when you want the same numbers computed from your live traffic instead of typed in.
Is anything I type sent to TapCub?
No. Almost every tool runs entirely in your browser. A few lookup tools (DNS, WHOIS, page speed) send only the domain or URL you enter, from your browser straight to a public service such as Cloudflare DNS, the domain registry or Google PageSpeed, and only when you press the button; each of those pages says where the request goes. We record that a tool page was viewed and used, like any other page — never the values.
Are the tools kept up to date?
Yes. Every tool page lists its version, an update history and the date each data source was last checked. Data such as crawler rules, public holidays and platform limits is re-checked on a schedule, and all tool updates are listed in one place.
Can I embed or link to a tool?
Linking is welcome. The pages have stable URLs under /tools. We do not offer an embed, but the formulas are documented on each page so you can reproduce them.
Why do my numbers differ from my analytics tool?
Usually the definition, not the arithmetic: who counts as a visitor, which event converts, and whether bots were removed first. Each tool lists the definition it assumes. See why UV never matches.
Will there be more tools?
When a question comes up often in support we turn it into a page. Suggestions go to contact.