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Developer Tools

Paste a payload, a token or a config and inspect it here. Regex, hashes, JWT decoding and format conversions stay in the tab. DNS lookups ask public resolvers, and those pages say so. Still treat any real secret as exposed once it has been copied around.

41 tools · free · no account

JSON Formatter & ValidatorNewJSON Formatter & Validator on Toolspire: Format, validate, minify and repair JSON online. Get the exact line and column of every error.XML to JSON ConverterNewXML to JSON Converter on Toolspire. Convert XML to JSON and JSON to XML online. Keeps attributes, arrays and leading zeros intact.DNS LookupNewCheck A, AAAA, CNAME, MX, NS, TXT, SOA and CAA records of any domain, see SPF and DMARC, and do reverse DNS for an IP address. Open DNS Lookup on Toolspire.DNS Propagation CheckerNewDNS Propagation Checker on Toolspire. Check DNS propagation worldwide: see the A, CNAME, MX. No account is required.JSON to CSV ConverterNewJSON to CSV Converter on Toolspire: Convert JSON to CSV for Excel or Google Sheets: nested objects become columns, lists are kept and big numbers stay exact.CSV to JSON ConverterNewCSV to JSON Converter on Toolspire: Convert CSV or data pasted from Excel to JSON: auto-detected delimiter, real numbers and true/false.UUID GeneratorNewUUID Generator on Toolspire: Generate UUIDs (GUIDs) online: random v4, sortable v7, v1, and name-based v5 and v3 — one or 10,000 at a time.URL Encoder / DecoderNewURL Encoder / Decoder on Toolspire: Encode or decode URLs and query strings online: %20, + and UTF-8 (Hindi, emoji) done right, errors pinpointed.Base64 Encoder & DecoderNewBase64 Encoder & Decoder on Toolspire: Encode text or files to Base64 and decode Base64 back — UTF-8, URL-safe Base64URL, data URLs for images.Markdown Live PreviewerNewMarkdown Live Previewer on Toolspire: Write Markdown with a live preview: GitHub tables, task lists, alerts and highlighted code. Export to HTML or PDF — free.JSON to XML ConverterNewConvert JSON to XML online: attributes, text, arrays and nested data, with a root element, CDATA and pretty or minified output. Free and private.Cron Expression GeneratorNewCron Expression Generator on Toolspire: Build and explain cron expressions in plain English with next run times. Supports Linux crontab, Quartz.CSS to Tailwind ConverterNewCSS to Tailwind Converter on Toolspire. Convert CSS to Tailwind classes online: hover, media queries, dark mode and gradients become variants.Hash GeneratorNewGenerate MD5, SHA-1, SHA-256, SHA-512, SHA-3, BLAKE3, CRC32 and HMAC hashes of text or files, and verify checksums. Free, fast and private — without uploading.CSV to Interactive ChartNewCSV to Interactive Chart on Toolspire: Turn CSV or Excel data into an interactive bar, line, area, pie or scatter chart online. Group and sum rows.JWT DebuggerNewJWT Debugger on Toolspire: Decode any JWT and verify its signature on your device: header, claims and expiry explained; HS256, RS256.JWT EncoderNewCreate and sign JWTs on your device with HS256, RS256, PS256, ES256 or EdDSA: edit claims, set expiry, generate keys and a JWKS. Keys never leave your device.Markdown to HTML ConverterNewMarkdown to HTML Converter on Toolspire: Convert Markdown to clean HTML online: GitHub tables, task lists and highlighted code, as a snippet or full page.Pixel-Perfect Screen RulerNewPixel-Perfect Screen Ruler on Toolspire: Screen ruler: a real-size cm and inch ruler calibrated with a bank card.Regex TesterNewRegex Tester on Toolspire: Live match highlighting, groups, replace, a plain-English explanation, unit tests and code for Python, PHP, Java, C# and Go.Hex to ASCII ConverterNewHex to ASCII Converter on Toolspire: Convert hex to ASCII or UTF-8 text and text to hex as you type. Reads 0x, \x and spaced hex.Binary to Text ConverterNewBinary to Text Converter on Toolspire: Translate binary code to text and text to binary, live. Handles spaced or joined 8-bit bytes, UTF-8 Hindi and emoji.HMAC GeneratorNewHMAC Generator on Toolspire: Generate HMAC-SHA256, SHA-512, SHA-1 or MD5 in hex or Base64, and verify GitHub, Stripe, Slack.Responsive Design TesterNewResponsive Design Tester on Toolspire: Test a website on phone, tablet, laptop and desktop screen sizes side by side. Works with localhost and pasted HTML.JSON to TypeScriptNewGenerate TypeScript interfaces, types or Zod schemas from JSON online. Finds optional properties, unions and nested types. Free, private, without uploading.JSON to YAML ConverterNewJSON to YAML Converter on Toolspire. Convert JSON to YAML and YAML to JSON online. Quotes yes, no and 0755 so every parser reads them the same.YAML to XML ConverterNewYAML to XML Converter on Toolspire: Convert YAML to XML and XML to YAML online. Handles attributes, lists, anchors and the root element..htaccess GeneratorNew.htaccess generator for Apache 2.4: 301 redirects, force HTTPS and www, security headers, password protection, compression and caching, each explained.Markdown to NotionNewMarkdown to Notion on Toolspire: Convert Markdown to Notion: preview the blocks, copy formatted text to paste into a page.HTML Entity EncoderNewEscape <, >, & and quotes so text is safe inside HTML, or decode those entities back into characters. The maths stays on your device.Mailto Link GeneratorNewMailto Link Generator on Toolspire: Build a mailto link with a percent-encoded subject and body, and refuse an address that has no @ and domain.HTML Table GeneratorNewTurn CSV or tab-separated rows into an HTML table, using the first row as the header and escaping <, > and &. The maths stays on your device.Chmod CalculatorNewTurn a three-digit chmod mode into rwx letters. 755 is rwxr-xr-x. Each digit is owner, group, then everyone else. Open Chmod Calculator on Toolspire.Semver CompareNewSemver Compare on Toolspire. Compare two numeric versions major.minor.patch. 1.2.10 is newer than 1.2.3, because 10 is greater than 3 as a number, not as text.Cron ExplainerNewCron Explainer on Toolspire: Explain a five-field cron expression made of stars, numbers and */step. “0 9 * * 1” is 09:00 on Monday.Regex EscapeNewRegex Escape on Toolspire: Escape a string so a regular expression matches it literally. a+b becomes a\+b, and the plus is no longer “one or more”.ULID GeneratorNewBuild a 26-character ULID. The first 10 characters encode the time. The last 16 are randomness from Crockford base32. Open ULID Generator on Toolspire.Basic Auth GeneratorNewBasic Auth Generator on Toolspire: Build an HTTP Basic Authorization header. The RFC example Aladdin and “open sesame” is Basic plus a fixed base64 string.HTTP Status LookupNewHTTP Status Lookup on Toolspire. Look up a common HTTP status code. 404 is Not Found. 418 is a teapot. Codes outside the short list are named as not on it.MIME Type LookupNewMIME Type Lookup on Toolspire. Map a file extension to a common MIME type. png is image/png. pdf is application/pdf. An unknown extension is said to be unknown.Luhn CheckerNewLuhn Checker on Toolspire: Run the Luhn check on a digit string. 79927398713 is valid. The algorithm doubles every second digit from the right and the total.

FAQ

Developer Tools: common questions

What belongs in Developer Tools on Toolspire?

Developer Tools is one collection on justtools.info. Open any tool and the page tells you whether the work stays on your device or a public lookup is required.

Is it safe to paste API keys or tokens?

Developer tools on Toolspire run client-side, so pasted data stays in this tab. As a habit, still rotate any secret that has been exposed anywhere.

Do the developer tools work offline?

Once a page has loaded, the JSON and XML tools need no network connection. The DNS tools ask public DNS servers for answers, so they need to be online.

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