Developer Tools
Ascii85 / Base85
Adobe Ascii85 encoding that packs four bytes into five printable characters, with the classic <~ ~> delimiters and z-compression.
ASCII Code Converter
Convert each character of text into its numeric ASCII code — decimal, hex, binary or octal — across many character sets.
Base32 / Base58
RFC 4648 Base32 (with optional base32hex), Crockford Base32 with its check symbol, z-base-32, and the Bitcoin / Flickr / Ripple Base58 alphabets, plus a Base58Check encode and verify panel.
Base62 Encode/Decode
Encode integers and byte strings in Base62 — 62 characters that never need escaping. Three common alphabets, a big-integer mode for short IDs, and length comparisons with Base58, Base64 and Base36.
Base64 Encode/Decode
Encode and decode Base64 and URL-safe Base64 for strings, JSON, XML and YAML — with MIME/PEM line wrapping, crypt/bcrypt/XXencode preset alphabets and a panel that works out which variant a pasted string belongs to.
Base64 File Converter
Free online file to Base64 encoder and decoder. Convert any file (PDF, DOCX, ZIP, MP3, MP4, etc.) to Base64 and decode Base64 back to a downloadable file. Supports drag & drop. All processing is…
Base64 Image Converter
Free online Base64 image encoder and decoder. Convert images (PNG, JPEG, GIF, WebP, BMP, SVG, ICO) to Base64 and vice versa. Output as Data URI, HTML, CSS, Markdown, JSON, or XML. All processing is…
Base64 Validator
Free online Base64 validator and repair tool. Validate Base64 strings, detect errors, fix invalid characters, correct padding, and convert between standard and URL-safe Base64. All processing is…
Base91 Encode/Decode
The densest printable encoding: 91 characters that carry about 23% overhead instead of Base64's 33%. The full alphabet is printed on the page, with a round-trip check and a size comparison against Base64 and Base85.
Binary Text
Translate text to and from runs of 8-bit or 7-bit binary numbers — space-separated or concatenated.
Multi-Layer Encoding Decoder
Unwind text that has been encoded several times over — Base64 inside URL encoding inside HTML entities — one layer at a time, with a confidence score and a reason for every candidate. Decoding only, never execution.
Encoding Detector
Detect the byte encoding of a file, hex dump or pasted text — BOM sniffing, strict UTF-8 validation and GBK/Big5/Shift-JIS candidates with confidence scores. Fully local replacement for the old server-side file encoder.
String Escaper
Escape and unescape strings for HTML, XML, JavaScript, Java, .NET, JSON, CSV and SQL, with optional \uXXXX for non-ASCII text.
Hex Base64 Converter
Free online Hex to Base64 and Base64 to Hex converter. Convert hexadecimal strings (0x, space-separated, or raw) to/from Base64. Supports multiple output formats. All processing is local — no data…
Hex Editor Adv
Advanced online hex editor. Insert/delete bytes, select & copy, compare binary files, and add bookmarks. All data processed locally.
Hex Text
Translate text to and from hexadecimal byte pairs, with optional 0x or %XX prefixes and flexible separators.
HTML Entity Converter - Encode / Decode / Reference
Encode text into HTML entities (named like ©, decimal © or hex ©), decode entity text back to characters, and browse/search the full HTML5 named character reference table. Options…
Morse Code
Encode text into international Morse code (A-Z, 0-9 and common punctuation) and decode Morse back into plain text.
Octal Text
Translate UTF-8 text to and from three-digit octal numbers per byte (000 – 377), with 0o or % prefixes and flexible separators.
Punycode / IDN
Convert international domain names and labels to and from their ASCII-compatible xn-- Punycode form (RFC 3492).
Quoted-Printable
RFC 2045 email-safe encoding with configurable soft line wrapping — the MIME counterpart to Base64.
ROT13 / ROT47
Classic Caesar ciphers: ROT13 over letters only, or ROT47 over the full printable ASCII range. The same action decrypts and encrypts.
UUEncode / UUDecode
The classic Unix “uuencode” binary-to-text transport: begin/end blocks, 45-byte lines and the famous backtick terminator.
AES Encrypt / Decrypt
Encrypt or decrypt with AES-128, -192 or -256 in GCM, CBC, CTR or ECB mode. Keys as raw hex or Base64 bytes or derived from a password with PBKDF2-HMAC-SHA256; random IV generation, AAD and GCM tag handling, and the OpenSSL command line that produces the same bytes printed beside the output.
Certificate Decoder
Paste a PEM, DER or PKCS#7 file, upload one, or open the built-in sample, and read the subject, the issuer, the serial number, both fingerprints, every extension with its parsed value, the signed certificate timestamps, and the raw DER in hexadecimal. Chains and signing requests are recognised and read too.
Certificate & Private Key Matcher
The deployment question in one page: is this the key for that certificate. The answer is proved by signing a challenge with the private key and verifying it with the public key inside the certificate, so it holds for RSA, ECDSA and Ed25519, and the report shows the fingerprints on both sides without ever printing the key itself.
CRC Calculator
Run 14 CRC parameter sets — CRC-8/CCITT, the CRC-16s, the CRC-32 quadruplets plus CRC-32C and cksum, three CRC-64s and Adler-32 — over text, hex bytes or files, with the polynomial, init, reflection and XOR-out of each printed alongside, and output in hex, decimal or octal.
CSR Generator
Choose RSA or ECDSA, fill in the subject and the alternative names, and get a private key together with a certificate signing request to hand to a certificate authority, both downloadable as PEM and the request as DER as well, with the signing algorithm, the fingerprints and the self-check command printed alongside.
Hash Generator
Hash text or files into MD5, SHA-1, SHA-256 or SHA-512 digests in hex or Base64 — SHA via WebCrypto, MD5 fully local.
HMAC & KDF Calculator
Compute a keyed MAC with HMAC-MD5 or the HMAC-SHA family over text, hex bytes or files, or derive key material with PBKDF2 (RFC 8018) and HKDF (RFC 5869). Keys and salts go in as text, hex or Base64; results come out in hex, upper-case hex, Base64 or Base64url, checked against the RFC test vectors.
JWT Debugger
Decode and verify JSON Web Tokens — pretty-printed header and payload, expiry badges, and HS/RS/ES signature validation with a pasted secret or PEM key.
Legacy Cipher Tool
The ciphers that must not be used for new work — DES, 3DES, RC4 (ARCFOUR) and Blowfish in ECB or CBC — kept for reading old archives and old protocol traces, each carrying the warning it has earned, with results checked against FIPS 46-3, RFC 6229 and Schneier's original Blowfish vectors.
OpenPGP Tool
Paste an ASCII-armored or binary OpenPGP key block and take it apart: the armor checksum, every packet in a tree with a hex dump, key versions, algorithms, fingerprints and key IDs, user IDs, expiry dates and the subpackets of every signature. Parsing only — nothing is decrypted or verified on this page.
Password Hash Generator
Generate and verify bcrypt, scrypt, Argon2id and PBKDF2 password hashes in the PHC string
format that PHP password_hash() and crypt() use, with the cost and
memory parameters laid out, the elapsed time of every run shown, and the OWASP minimum
defaults explained field by field.
RSA Encrypt / Decrypt
Generate RSA key pairs from 2048 to 4096 bits and export them as PEM in four formats, import a public or private key you already have, encrypt with RSA-OAEP, sign with PKCS#1 v1.5 or PSS, and convert between the SPKI, PKCS#8 and PKCS#1 encodings that keys travel in.
Self-Signed Certificate Generator
Produce a certificate that signs itself, with the validity period, the key usage, the extended key usage, the basic constraints and the alternative names under your control, for a test server or an internal network. The page explains in plain terms why no browser will trust it without being told to.
SM2 Encrypt / Decrypt / Sign
The Chinese national public-key algorithm (GB/T 32918-2016): generate key pairs, sign and verify with the standard's SM3-with-ZA hashing, encrypt and decrypt in the C1C3C2, C1C2C3 and DER wire formats, and export keys in the UN/SEC1 layout OpenSSL uses.
SM3 Hash Generator
The Chinese national hash function (GB/T 32905-2016): 256-bit digests over text, hex bytes or files, keyed HMAC-SM3 with the GB/T 15852.2 test vectors, and an explanation of how SM3 relates to SHA-256 and where each is mandated.
SM4 Encrypt / Decrypt
The Chinese national block cipher (GB/T 32907-2016): 128-bit blocks and keys in ECB and CBC mode with PKCS#7 padding, text, hex or Base64 input, and the key-schedule and S-box logic documented in the explanation section.
SM9 Identity-Based Crypto
The Chinese national identity-based standard (GB/T 38635-2020), where an email address or phone number works directly as the public key: how IBE encryption and IBS signatures work, how the KGC trust model differs from certificate PKI, and the official 256-bit BN curve parameters. Explanation page — read-only.
SSL Certificate Checker
Turn a certificate into a verdict: expired or expiring, inside the current validity ceiling, does the name you need appear in the subject alternative names, is the chain complete and are the signatures inside it sound, is the key or the signature algorithm too weak, and which extensions a modern client expects but this one is missing.
HTTPS Configuration Audit
Paste the response headers from a site, optionally with its certificate and a page of its source, and get one report covering the transport security headers, the certificate chain and the mixed content in the page, each finding tied to the rule it comes from, with an opt-in reachability probe that says plainly when it cannot see what it was asked about.
cURL Command Converter
Paste an existing cURL command to inspect and convert it into Node.js, Python or PowerShell, or just beautify the curl itself.
Data Uri Builder
Free online Data URI builder. Generate data: URIs from Base64 strings with any MIME type. Output as Data URI, HTML <img>, HTML <video>, HTML <audio>, CSS url(), HTML <link>…
DNS Lookup
Query A, AAAA, CNAME, MX, TXT, NS, SOA, SRV, CAA and PTR records and compare what several public resolvers answer side by side, with the TTL, the DNSSEC flag, the CNAME chain and a plain explanation when the answers disagree.
HTTP Header Parser
Paste a request or a response and read it field by field: what every header means, which side it belongs to, a full cookie breakdown, and a syntax audit.
HTTP Request Builder
Build a request from ready-made templates (JSON, form, file upload) and instantly get cURL, Node.js fetch, Python requests or PowerShell code.
HTTP Status Codes
The full status code list with grouped colouring, full text search and filtering, a short wizard that picks the right code for a situation, and a comparison of the pairs that are easy to confuse, such as 401 against 403 and 301 against 308.
IDN Homograph Checker
Check a Unicode or xn-- domain for mixed scripts, look-alike characters, compatibility forms and over-long labels, and understand why a browser may display it in Punycode instead.
IP Lookup & Geolocation
Find your own address, look up any IPv4 or IPv6 address, read the network, country, city, time zone and connection type behind it, and check in the browser whether a WebRTC connection exposes an address you did not expect.
IP / CIDR Subnet Calculator
Turn an address and a prefix into network address, mask, host range and host count, read the binary and hexadecimal forms, reverse a mask back to its prefix, and split a block into subnets with the address class and special ranges marked.
MIME Type Lookup
Look up MIME types by file extension or vice versa across roughly 800 common entries with category and usage notes — handy for headers and upload filters.
OpenAPI / Swagger Viewer
Render an OpenAPI 3.0 / 3.1 or Swagger 2.0 document (YAML or JSON) into a browsable reference: endpoints by tag, parameters, example bodies from schemas, responses, and Try-it calls.
Port & Service Lookup
Search the port registry by number or by service name in either direction, filter by TCP or UDP and by well-known, registered or dynamic range, and read a note on the services that are exposed by accident far more often than on purpose.
REST API Client / Tester
Send HTTP requests to any endpoint with method, headers, query, cookies, Basic/Bearer/API-key auth, JSON / form / text bodies and multipart file upload.
Reverse IP Lookup
Go from an address back to the name its owner published for it, see the response status and the resolver that answered, and walk the neighbouring addresses in the same block to read the naming scheme of the network.
Robots.txt Parser
Lint a robots.txt the way RFC 9309 says a crawler reads it: groups merged, wildcards expanded, longest-match rules, and a tester that answers allow or deny for any user agent and path.
Security Headers Check
Score response headers against the OWASP list: every missing header is a deduction, every finding comes with copy-ready nginx, Apache and Express fix lines.
URL Encoders
Percent-encode and decode URL components (full or lightweight) plus JSON, XML and YAML string escaping, bidirectionally.
URL Parser & Safety Check
Break a URL into scheme, host, port, path, query and fragment, view every level of percent and entity decoding, edit or clear the query parameters including the tracking ones, and read a safety panel covering embedded credentials, look-alike hostnames and other common tricks.
Percent-Encoding Inspector
See how one string is percent-encoded by encodeURIComponent, encodeURI and form-urlencoded side by side, with a per-character byte table, RFC 3986 reserved-character roles and a multi-layer decoder for double-encoded text.
User Agent Parser
Paste any User-Agent string to identify browser, engine, OS, device vendor/model/type and CPU, with realistic presets and JSON export.
WebSocket Tester
Connect to a ws:// or wss:// server, negotiate sub-protocols, send text or JSON messages and follow the full lifecycle with close codes in one log.
Clean & Deduplicate CSV
Trim whitespace, repair quoting, drop empty rows and remove duplicate rows — with a preview of every change before you download.
CSV Column Operations
Reorder, rename, extract, delete, insert, split or merge columns across the whole table in one pass, with a preview.
CSV → JSON/XML/YAML/HTML/SQL
Convert delimited data to JSON arrays, XML documents, YAML sequences, HTML tables or SQL (CREATE TABLE + INSERT) with dialect, type-detection and formatting options.
CSV Converter
Online convert Excel xlsx/xls/xl/xlt/xltx/slk/xlw/xml or Calc ods fods ots sxc fods stc xlsb xlc ett dif wk1 wks wb2 to csv file
Split / Merge CSV
Split a large CSV file into parts by row count or number of parts, keeping the header in every part or only the first. Merge files back by column name or position with a column difference report.
CSV / TSV Compare
Diff two delimited tables side by side and see every cell-level add, remove or change highlighted in a visual grid.
CSV TSV Editor
Open, view and edit CSV or TSV files online for free. The delimiter (comma, tab, semicolon) is detected automatically. Edit any cell in the table, add or remove rows, select and delete whole columns…
JSON Compare
Diff two JSON documents side by side with colour-coded add/remove/change markers and a summary of the differences.
JSON ↔ CSV / TSV
Convert between JSON (array of objects) and CSV or TSV with header mapping, delimiter selection and previews.
JSON Formatter
Format, minify and validate JSON with inline location of syntax errors — ideal for API responses and config files.
JSONPath Evaluator
Test JSONPath expressions with live match highlighting, pretty-printed results, count and an expression syntax reference.
JSON Schema Generator / Validator
Validate JSON documents against a JSON Schema (draft-07) with precise error paths, and generate a starter schema from sample data.
JSON → SQL / TOML
Export a JSON array of objects as SQL INSERT statements for MySQL/PostgreSQL, or as a TOML document, with type-aware value rendering.
JSON ↔ String
Escape a JSON object into a string literal or parse an escaped string back into formatted JSON, with single/double quote modes.
JSON Viewer / Editor
Browse JSON as a colour-coded tree and edit inline: change values and types, add, rename and delete keys, then export formatted or minified.
JSON ↔ XML
Convert between JSON and XML with attribute handling, indentation control and two-way round-trip options.
JSON ↔ YAML
Convert between JSON and YAML with optional flow style, comments preserved where possible, and nested data support.
RSS / Atom → JSON
Convert RSS 2.0 or Atom feed XML into clean JSON with item arrays and metadata, ready for further processing.
XML / HTML Compare — Free Online Markup Diff Tool
Free online XML and HTML comparison tool. Compare two XML or HTML documents side-by-side and see structural differences. All processing is local — no data uploaded.
XML → CSV
Turn XML documents into clean delimited CSV/TSV output, reading elements and attributes in document order.
XML Tools
Format, minify, validate and explore XML documents with a tree view — covers markup such as SVG and RSS too.
YAML Compare — Free Online YAML Diff Tool
Free online YAML comparison tool. Compare two YAML documents side-by-side and see structural differences. All processing is local — no data uploaded.
YAML Tools
Validate and format YAML with optional key sorting, a tree view, and conversion to JSON for config inspection.
C / C++ / C# / Java Formatter
Reformat C, C++, Objective-C, C# and Java with real clang-format, choosing LLVM, Google, Chromium, Mozilla, WebKit, Microsoft or GNU styles.
Code Formatter
Beautify JavaScript, TypeScript, JSX/TSX, JSON5, GraphQL, Vue SFC, PHP and TOML with Prettier, choosing tab width, quotes and semicolons.
Code Playground
Run JavaScript in a sandboxed iframe with colour console output, or preview full HTML+CSS+JS pages live and download them — broken loops can always be stopped.
Code Screenshot Generator
Turn code snippets into polished Carbon-style PNG images — highlight.js syntax colours, window chrome, line numbers and four themes, exported at retina sharpness.
CSP Generator
Build a Content-Security-Policy directive by directive, with a sha256 hash generator for inline scripts and a warning when a combination will not do what it looks like it does.
CSS Tools
Format or minify CSS, SCSS, LESS and SASS, compile and reverse between preprocessor dialects for stylesheet cleanups.
JSON → Classes / Schema
Generate C#, Java, TypeScript or PHP classes, TypeScript interfaces or JSON Schema from sample JSON and XML documents.
Go Formatter
Format Go source with the official gofmt engine compiled to WebAssembly — deterministic canonical Go style with tabs and column alignment.
HTML Table Generator - visual table builder
Visually build an HTML table: set rows, columns, caption, header, borders, spacing, colours and alignment, type into a live grid or paste TSV/CSV/Excel data, then get copy-paste-ready HTML code…
HTML Tools
Format or minify HTML with a live preview pane and syntax validation for hand-written and generated markup.
Mermaid Chart Editor - Flowchart, Sequence, Gantt & More
Edit Mermaid diagrams in your browser and watch them render instantly: flowcharts, sequence, class, state, gantt, pie, timeline and ER diagrams. Switch Default / Dark / Neutral / Forest themes, then…
Python Formatter
Reformat Python 3 with the Ruff formatter (Black / PEP 8 style) — choose indent width, quote style, line width and magic trailing commas.
Regex Tester
Live regex matching with highlight, match list and capture groups, flags, and a library of common patterns. Invalid patterns are reported inline.
Shell Script Formatter
Format Bash, POSIX sh and mksh scripts with shfmt — normalize indentation, redirect spacing, function layout and case bodies.
Database Connection Tester
Free local database connection string builder and tester. Fill in host, port, database and credentials to get ready-to-paste JDBC, ADO.NET, ODBC, Python and SQLAlchemy connection strings for MySQL…
Database Migration Generator
Free local database migration generator. Paste a before and after schema (CREATE TABLE DDL or schema JSON) and get up and down migration scripts: added and dropped tables, added, removed and…
ERD Designer
Free local ERD and database schema designer. Build tables, columns, primary keys, foreign keys and relationships in a structured editor, watch the entity relationship diagram redraw live, then…
SQL Formatter
Beautify, minify or validate SQL queries across six dialects, with keyword case and indent width options.
SQL Query Builder
Paste CREATE TABLE DDL or define columns by hand, tick the columns, add WHERE/JOIN/ORDER BY, and generate SELECT, INSERT, UPDATE or DELETE skeletons for Standard SQL, MySQL or PostgreSQL.
SQL To ERD
Free local SQL to ERD converter. Paste one or more CREATE TABLE statements and get an entity relationship diagram: tables become entities, columns become attributes with PK/FK tags, and FOREIGN KEY…
📅 Cron Expression Builder
Build a 5-field cron expression visually or paste one to decode it — minutes, hours, day-of-month, month and day-of-week with presets, plus the next five run times.
🔢 Time Calculator & Statistics
Calculate time durations, track work hours, find your exact age, count business days between dates, and perform time arithmetic.
⏲ Timer & Productivity Tools
Countdown to any event, use a precise stopwatch, run Pomodoro sessions, decode Cron expressions, and calculate optimal sleep/wake times.
📅 Timestamp & Date Converter
Convert Unix timestamps to human-readable dates and vice versa. Format dates in ISO 8601, RFC 2822 or custom patterns, parse date strings, calculate differences, add/subtract days, and find week numbers.
🌎 Timezone & World Clock
Convert times between any timezone, plan international meetings, view a live world clock, and work with UTC offsets.
Batch File Hash & Manifest Verifier
Drop a whole folder and get the MD5, SHA-1, SHA-256, SHA-384 or SHA-512 of every file at
once, then paste or upload a checksum manifest - GNU sha256sum output, BSD
openssl dgst lines, SFV files - and see which files verify, which mismatch and
which are missing. Results copy back out as sha256sum-compatible lines.
Binary File Compare
Line two files up byte by byte: every differing offset, a stacked hex diff with context, a density map, and which bits flipped. A block-aligned mode detects insertions and deletions in the middle of a file; reports export to TXT and CSV.
Duplicate File Finder
Finds byte-identical files by content in three passes - size filter, SHA-256 grouping, full byte comparison - so renamed and re-dated copies are caught and same-name-different-content files are not. Each cluster shows the space it wastes, and the deletion checklist exports as CSV.
Online convert text/html file encoding
Online convert text/html file encoding. Auto detect original encoding, convert to UTF-8, UTF-16, UTF-32, ANSII, UNICODE, GB2312, GBK, GB18030, Big5, Shift-JIS, EUC-KR and more.
File Renamer
Batch-rename with a preview of every new name before anything is committed: find & replace, insert text, sequential numbering with padding and tokens, case changes, trimming, and sanitizing that handles Windows-invalid characters and reserved device names. Download the renamed files one by one or as a ZIP.
File Splitter & Merger
Cut any file into numbered parts by size or count - name.001,
name.part01, name.split.001, name[1].ext - and join a
part series back byte-exact, with gap detection, a size check and a SHA-256 of the reassembled
file to compare against the original.
File Type Detector
Reads the magic bytes inside each file - not the extension - and reports the real format from a table of 60+ signatures: images, Office, ODF, EPUB, archives, media, fonts, executables, databases. Renamed files are flagged as extension mismatches, and where a header carries them, dimensions, PDF version and MP4 brand are shown too.
INI / ENV Compare — Free Online Config File Diff Tool
Free online INI and ENV file comparison tool. Compare two config files side-by-side and see structural differences. Supports both INI (section-based) and ENV (flat key-value) formats. All processing…
.gitignore Generator
Assemble a .gitignore from categorized template libraries for languages, frameworks, tools, OS and IDEs — tick, merge, deduplicate, copy or download.
Programmer Calculator
Free online programmer calculator. Type one expression with 0x hex, 0b binary and 0o octal literals, bitwise AND OR XOR NOT, shifts and math, and see the result update live in decimal, hexadecimal…
Test Data & Mock Data Generator
Define typed columns (names, e-mails, numbers, dates, UUIDs, words…) and produce N seeded mock/test rows as CSV, TSV, JSON, HTML or bulk SQL INSERTs.
UUID / ULID / NanoID Generator
Batch UUID v4 (and GUID), time-sortable ULID or compact URL-safe NanoID identifiers with format options — cryptographically random and collision-resistant.