Developer Utilities

.env to JSON Converter Convert .env (dotenv) files to JSON: handles quotes, export, comments, multi-line values and ${VAR} expansion. API Tester (REST Client) Send GET, POST, PUT, PATCH and DELETE requests to REST APIs from your browser and inspect status, headers and pretty-printed JSON. Area Chart Maker Create area charts online from CSV or JSON data: filled line graphs with multiple series, smooth curves and SVG export. ASN.1 Decoder Parse DER/BER ASN.1 structures from PEM, Base64 or hex into a readable tree with OID names, strings, times and integers. Bar Graph Maker Make bar charts online from CSV or JSON. Grouped bars for multiple series, negative values, custom colours and SVG export. Barcode Generator Generate Code 128, EAN-13, UPC-A, Code 39, ITF-14, ISBN, Data Matrix, PDF417 and more barcodes. Download PNG or SVG for free. Basic Auth Header Generator Build an HTTP "Authorization: Basic" header from username:password, or decode an existing Basic auth header back to credentials. Bcrypt Hash Generator Generate a bcrypt password hash ($2y$) with a configurable cost factor, compatible with PHP password_hash and Laravel. Broken Link Checker Find broken links on a web page: every link is checked and 404s, errors and redirects are listed. Checksum Calculator Calculate MD5, SHA-1, SHA-256, SHA-512, CRC-32 and more checksums of a file or text at once. Chmod Calculator Convert Linux file permissions between octal (755) and symbolic (rwxr-xr-x) with checkboxes, including setuid, setgid and sticky bits. CIDR / Subnet Calculator Calculate network, broadcast, netmask, wildcard, host range and host count for any IPv4 or IPv6 CIDR block. Code to ASCII Convert source code or any text into a list or array of ASCII character codes for JavaScript, Python or C. Content Security Policy Evaluator Parse a Content-Security-Policy header and flag risky directives such as unsafe-inline, wildcards, missing object-src and base-uri. Credit Card Validator Check credit card numbers with the Luhn algorithm, detect Visa, Mastercard, Amex and more, and verify length. Runs 100% locally. Cron Expression Parser Translate cron expressions into plain English and list the next 10 run times. Supports macros, seconds fields and Quartz syntax. Crontab Generator Build a crontab line from presets or custom fields, with a plain-English explanation and a preview of the next run times. CSR Decoder Decode a PKCS#10 certificate signing request to check the subject, SANs, key size and signature before you send it to a CA. CSR Generator Generate an RSA private key and certificate signing request (CSR) with SANs in your browser — the private key never leaves your device. cURL to Axios (Node.js) Converter Convert curl commands to Node.js axios requests with params, headers, JSON data, auth, form-data uploads and timeouts. cURL to C# Converter Convert curl commands to C# HttpClient code for .NET with headers, content types, basic auth, multipart and TLS options. cURL to Go Converter Convert curl commands into Go code using net/http — method, headers, JSON or form body, basic auth, timeouts and multipart uploads. cURL to Java Converter Convert curl commands to Java 11+ java.net.http.HttpClient code with headers, body, redirects and timeouts. cURL to JavaScript Fetch Convert curl commands into JavaScript fetch() code with method, headers, JSON body, form data, basic auth and timeouts. cURL to PHP Converter Convert curl commands into PHP code using the curl_* functions: method, headers, body, auth, cookies and SSL options. cURL to PHP Guzzle Converter Convert curl commands to PHP Guzzle requests using json, form_params, multipart, query and auth options. cURL to Python Requests Convert curl commands into Python requests code: headers, params, JSON or form data, files, cookies, auth and timeouts. cURL to Rust Converter Convert curl commands to Rust using the reqwest crate, with JSON bodies via serde_json, headers, auth and timeouts. Date & Time Calculator Calculate the difference between two dates or add/subtract days, weeks, months and years from a date. DNS Lookup Look up A, AAAA, CNAME, MX, NS, TXT and SOA records for any domain. Docker Run to Docker Compose Convert one or more docker run commands into a docker-compose.yml: ports, volumes, env, restart, networks, healthchecks and more. Doughnut Chart Maker Build doughnut (donut) charts online from CSV or JSON. Shows the total in the centre, percentages per segment and exports SVG. ECDSA & Ed25519 Key Generator Generate elliptic-curve key pairs (P-256, P-384, P-521) and Ed25519 keys as PEM or JWK for JWT signing, TLS and APIs. Email Extractor Extract e-mail addresses from any text: remove duplicates, sort, lowercase, filter by domain and choose a separator. Shows a count. File Type Checker Find out what a file really is from its content, not its name. Detects 150+ formats and warns when the extension does not match. Gzip Compress Compress text with gzip and get the result as Base64 or hex, ready for APIs, headers or test fixtures. Gzip Decompress Decompress gzip data that is Base64 or hex encoded and view the original text online. Hash Identifier Identify hash types from their format: MD5, SHA-1/256/512, bcrypt, Argon2, sha512crypt, NTLM, MySQL, phpass, Django and more. Hostname to IP Resolve a hostname to its IPv4 and IPv6 addresses. Hreflang Tag Generator Generate hreflang annotations for multilingual sites as <link> tags, sitemap entries or HTTP headers, with code validation. Htpasswd Generator Create .htpasswd entries for Apache and Nginx basic auth with bcrypt, APR1-MD5 or SHA-1 — one username:password per line. HTTP Request Headers Viewer See the HTTP request headers your browser sends: User-Agent, Accept, Sec-Fetch and client hints, plus headers added by a CDN or proxy. Cookie values hidden. HTTP Status Codes Searchable list of the HTTP status codes in use, from 100 to 511, with a plain explanation of when each response is used. Invisible Character Detector & Remover Find zero-width spaces, non-breaking spaces, BOMs, bidi overrides and other hidden Unicode characters — then remove or escape them. IP Address Lookup Look up the approximate country, region, city, time zone and network (ASN) of any public IP address, from a local database. IP to Hostname Reverse-DNS lookup: find the hostname (PTR record) for an IP address. JavaScript Key Code Finder Press any key to see its event.key, event.code, legacy keyCode, location and modifier state for JavaScript keyboard handlers. JavaScript Tester Run JavaScript online and see console.log, warnings, errors and tables instantly in a safe, sandboxed browser console. jq Playground Run jq filters on JSON in your browser with real jq 1.8: live output, -r -c -s -n -S and --arg options, clear errors and a clickable cheat sheet. JSON to .env Converter Turn JSON configuration into .env KEY=value lines with nested keys joined by __ and values quoted safely. JSONPath Tester Test JSONPath expressions online against your JSON. Supports filters, wildcards, recursive descent and slices, returning values or paths. JWT Decoder Decode a JSON Web Token to inspect its header, payload claims and expiry time, and verify its signature with your key. Runs locally. JWT Encoder & Generator Create and sign JSON Web Tokens with HS256, RS256, ES256, PS256 or EdDSA using a secret or PEM key. Signing happens in your browser. JWT Verifier Verify a JWT signature with a shared secret, PEM public key, X.509 certificate or JWKS and check exp, nbf, iss and aud claims. Line Graph Maker Create line graphs online from CSV or JSON data. Multiple series, axis labels, custom colours and free SVG download. Mermaid Live Editor Write Mermaid flowcharts, sequence, class, ER, Gantt and state diagrams with a live preview, then export SVG or PNG. Meta Tag Generator Generate SEO meta tags for your page head: title, description, keywords, robots, canonical, Open Graph and Twitter cards. MIME Type Lookup Find the MIME / Content-Type for a file extension or the extensions for a media type — about 150 common types. MongoDB ObjectId Generator Generate valid 12-byte MongoDB ObjectIds for the current time or any date, as hex, ObjectId() or Extended JSON. MongoDB ObjectId to Timestamp Extract the creation date from MongoDB ObjectIds and see the random and counter parts; also builds a date-range _id query. MX Lookup Find the mail exchange (MX) servers and priorities for a domain or email address. Nameserver Lookup Find the authoritative nameservers (NS records) of any domain. Nano ID Generator Generate secure, URL-friendly Nano IDs with custom length and alphabet, plus a collision-probability estimate. Phone Number Validator & Formatter Validate phone numbers for 240+ regions and format them as E.164, international and national, with line type detection. Pie Chart Maker Create pie charts online from label/value data. Automatic percentages, legend or outside labels, custom colours and SVG download. QR Code Generator Create free QR codes for URLs, text, Wi-Fi, vCards, e-mail, SMS, phone numbers, locations and events. Custom colours, PNG and SVG. QR Code Reader & Scanner Scan QR codes from an image, screenshot or your camera and see the content — links, Wi-Fi passwords, contacts — safely before opening. Random Byte Generator Generate cryptographically secure random bytes as hex, Base64, decimal, binary or a code array. Random CSV Generator Generate realistic fake CSV test data — names, emails, addresses, dates and more — with custom fields. Random Data from Regex Generate random strings that match a regular expression — ideal for test data such as IDs, codes and formats. Random JSON Generator Generate realistic fake JSON test data — names, emails, addresses, dates and more — with custom fields. Random String Generator Generate random strings of any length from letters, digits, hex, URL-safe or custom character sets. Random TSV Generator Generate realistic fake TSV test data — names, emails, addresses, dates and more — with custom fields. Random XML Generator Generate realistic fake XML test data — names, emails, addresses, dates and more — with custom fields. Regex Cheat Sheet Interactive regex cheat sheet: anchors, classes, quantifiers, groups, lookarounds, flags and Unicode, with clickable examples and a flavour table. Regex Escape Escape special characters so any text can be matched literally inside a regular expression in JavaScript, PCRE, Python or Java. Regex Explainer Break a regular expression into tokens and explain each part in plain English: groups, quantifiers, classes, anchors and lookarounds. Regex Patterns Library Copy-ready regex patterns for email, phone, URL, IP, dates, numbers, UUIDs, postal codes and passwords, each with examples and a live test box. Regex Tester Test JavaScript regular expressions live: highlight matches, inspect capture groups and named groups, try flags and preview replacements. Responsive Website Tester Preview any website on phone, tablet, laptop and desktop screen sizes side by side to check your responsive design. RSA Key Pair Generator Generate RSA 2048, 3072 or 4096-bit public/private key pairs in PEM (PKCS#8, PKCS#1) or JWK format with WebCrypto, entirely offline. SAML Response Decoder Decode Base64 or deflated SAMLResponse and SAMLRequest messages into readable XML and summarise issuer, NameID, conditions and attributes. Scatter Plot Maker Make scatter plots online from x,y data. Multiple series or groups, linear trend lines, custom colours and SVG download. Self-Signed Certificate Generator Create a self-signed SSL/TLS certificate and RSA key for localhost, dev servers or internal tools. Generated locally with WebCrypto. SemVer Checker & Range Tester Validate, compare and sort semantic versions and test them against npm-style ranges like ^1.2.0, ~2.3 or >=1.0 <2. Snowflake ID Decoder Convert Twitter/X, Discord, Instagram and other Snowflake IDs to timestamps and show worker, process and sequence bits. SSH Key Generator Generate OpenSSH key pairs (Ed25519, RSA, ECDSA) in id_ed25519 / id_rsa format with fingerprint — created locally, like ssh-keygen. SSL Certificate Decoder (X.509) Decode PEM or DER X.509 SSL/TLS certificates: subject, issuer, SANs, validity, key type, extensions and SHA-256 fingerprints. String Builder Turn multi-line text into StringBuilder / string concatenation code for Java, C#, JavaScript, Python, PHP or Go. String Byte Size Counter Count how many bytes a string uses in UTF-8, UTF-16 and UTF-32, plus characters, code points and Base64/URL-encoded size. Time Sheet Calculator Add up weekly work hours from start and end times with breaks. Calculates overtime per day or week and optional gross pay. TOTP / 2FA Code Generator Generate live TOTP 2FA codes from a Base32 secret or otpauth:// URI, create new secrets and QR codes for authenticator apps. TXT Record Lookup Read the TXT records of a domain, including SPF, DKIM and verification strings. ULID Decoder Decode ULIDs to their embedded timestamp and random part, and convert between ULID and UUID formats. ULID Generator Generate sortable ULIDs (Universally Unique Lexicographically Sortable Identifiers) with monotonic ordering, in bulk, using secure randomness. Un-Google Link Remove Google redirect wrappers (google.com/url, AMP, image results) and tracking parameters to get the real destination URL. Unix Timestamp Converter Convert Unix epoch timestamps to human dates and dates to timestamps, in UTC, local time and any time zone. URL Decode Decode percent-encoded URLs and query strings back into readable text, with full UTF-8 support. URL Encode Percent-encode text or URLs online so they can be used safely in query strings, paths and form data. URL Parser Break a URL into scheme, host, port, path, query parameters and fragment. Decodes values and parses many URLs at once. URL Slug Generator Convert titles into clean, SEO-friendly URL slugs: lowercase, hyphens, accents transliterated, stop words and length limits. One per line. User Agent Parser Parse user agent strings to identify browser, version, rendering engine, operating system, device type and bots. UUID Generator Generate random UUID v4 or time-ordered UUID v7 identifiers in bulk, with case, hyphen and brace options. UUID Validator & Decoder Validate UUIDs/GUIDs and decode version, variant and embedded timestamps for v1, v6 and v7 — many at once. vCard QR Code Generator Put your contact details in a vCard QR code for business cards and badges: name, company, phone, e-mail, website and address. Website to IP Address Find the IP address a website points to from its link, with plain-English notes on CDNs, shared hosting and changing results. What Is My IP Address See your public IP address (IPv4 or IPv6) instantly, whether it is public, private or CGNAT, its reverse DNS hostname and your browser details. What Is My Screen Resolution? See your screen resolution, browser viewport size, device pixel ratio, colour depth and media-query features instantly. WhatsApp Link Generator Create a wa.me click-to-chat link with a pre-filled message for your website, e-mail signature or QR code. Wi-Fi QR Code Generator Make a Wi-Fi QR code so guests can join your network by scanning — SSID, password and security type, printable PNG or SVG. WordPress Password Hash Generator Create a WordPress password hash for the wp_users table: bcrypt for WordPress 6.8+ or phpass for older versions. XML Sitemap Generator Turn a list of URLs into a valid sitemaps.org XML sitemap with optional lastmod, changefreq and priority — ready for Search Console. XPath Tester Test XPath expressions online against your XML. See matched nodes, attributes, strings, numbers or booleans instantly. Zlib Compress Compress text with zlib (DEFLATE) and output Base64 or hex, compatible with gzcompress and zlib.compress. Zlib Decompress Inflate zlib or raw DEFLATE data from Base64 or hex and read the decompressed text.