Developer tools that respect your privacy

Format, beautify, and validate JSON online. Free, fast, and 100% local — your data never leaves your browser.

Validate JSON online with instant error location and structure statistics (depth, keys, node types). 100% local — your JSON never leaves the browser.

Validate a JSON payload against a JSON Schema online. Supports Draft 2020-12, format validation (date-time, uuid, email, uri), and shows errors by JSON pointer path. 100% local — nothing is uploaded.

Generate a JSON Schema from a sample JSON — output as standard Draft 2020-12, OpenAI function calling schema, or Anthropic tool_use schema. Powers LLM structured output pipelines.

Test JSONPath expressions against sample JSON online. Get instant, highlighted results for queries like $.store.book[*].author.

Compare two JSON documents structurally and see added, removed, and changed values by path. Handles nested objects, arrays, and type changes.

Convert JSON to TypeScript interfaces instantly. Generate strongly-typed TS types from any JSON sample.

Convert JSON to Go structs online. Generates idiomatic Go structs with proper json tags and PascalCase field names.

Convert JSON to Python @dataclass definitions with typed fields. snake_case field names, nested classes, List[T] for arrays, and JSON-key alias comments. 100% local.

Convert JSON to PHP 7.4+ classes with typed properties. Generates one class per nested object, phpdoc @var array<T> for typed arrays, and camelCase property names. 100% local.

Convert JSON to Java POJOs with Jackson @JsonProperty annotations, camelCase field names, List<T> for arrays, and generated getters/setters. Optional package declaration. 100% local.

Convert JSON to C# classes with System.Text.Json [JsonPropertyName] attributes, PascalCase properties, List<T> for arrays, and optional namespace. Works in .NET 6 / 7 / 8 / 9. 100% local.

Encode and decode Base64 strings online. Supports UTF-8 text and URL-safe Base64. All processing runs locally in your browser.

Encode and decode Base32 strings online (RFC 4648). Handles TOTP / Google Authenticator secrets, DNSSEC records, and other case-insensitive binary-to-text formats. 100% local.

Encode and decode Base58 strings online — the alphabet used by Bitcoin addresses, Solana public keys, IPFS CID v0, and Flickr short links. 100% local, no padding, human-safe.

Convert internationalized (IDN) domain names to and from their ASCII xn-- form. Follows RFC 3492 exactly — the same encoding your browser and DNS resolver use. 100% local.

Escape and unescape Unicode sequences online. Convert any text to \uXXXX / \u{XXXX} form, or reverse escape sequences back to readable text. Handles surrogate pairs and emoji. 100% local.

Percent-encode and decode URLs online. Handles query strings, path segments, and special characters correctly.

Encode and decode HTML entities (&amp;, &lt;, &gt;, &quot;, numeric references). Useful for sanitizing user content or debugging escaped markup.

Apply ROT13 to any text online — a symmetric letter-rotation cipher (rot13(rot13(x)) == x). Also supports ROT-N with custom shift, and ROT47 for full ASCII coverage. Runs 100% locally.

Convert images to Base64 data URLs online. Drop or select any image and copy the ready-to-paste data URI for CSS, HTML, or JSON.

Decode Base64 strings back to images. Paste a data:image/... string or raw Base64, and see the decoded image instantly. Useful for debugging data URIs and embedded images. 100% local.

Decode JSON Web Tokens (JWT) to inspect the header, payload, and signature. Runs entirely in your browser — tokens are never sent to any server.

Encrypt and decrypt text with AES (128 / 192 / 256, GCM authenticated or CBC legacy) using a password. PBKDF2 key derivation with 200,000 iterations. 100% local — the Web Crypto API runs entirely in your browser.

Generate RSA key pairs (2048, 3072, or 4096 bits) online for OAEP encryption, PSS signing, or RS256 JWTs. Exports PKCS#8 private key + SPKI public key as PEM, JWK, or DER (hex/base64). 100% local — the Web Crypto API runs in your browser, private keys never leave the tab.

Paste an RSA or EC private key (PEM PKCS#8 or JWK) and instantly extract the matching public key in PEM (SPKI), JWK, or DER format. Perfect for publishing a JWKS endpoint, verifying a token against a private-key-only backup, or distributing a public key to peers. 100% local — the private key never leaves your browser.

Encrypt text with an RSA public key or decrypt ciphertext with the private key, using RSA-OAEP (SHA-256/384/512). Accepts PEM (PKCS#8 / SPKI) or JWK. 100% local — keys and plaintext never leave your browser tab.

Sign or verify messages with ECDSA (P-256, P-384, P-521) using PEM or JWK keys. Outputs both JOSE / P1363 (JWT-compatible) and DER (OpenSSL-compatible) signatures. 100% local via the Web Crypto API.

Convert cURL commands to Python (requests), JavaScript (fetch), Node.js, Go (net/http), PHP, or Java (HttpClient). Parses -H, -d, --data-urlencode, -F, -u, --json and more. 100% local.

Parse any URL into scheme, host, port, path, and query parameters — or build a URL from scratch with a form. Great for debugging redirect chains, tracking pixels, and OAuth flows. 100% local.

Calculate IPv4 subnets from CIDR notation online. Get network address, broadcast, netmask, wildcard, usable host range, IP class, and binary representation. 100% local — nothing leaves your browser.

Convert colors between HEX, RGB, HSL, and HSV instantly with a live color preview and copy-ready CSS strings. Free, no signup, runs entirely in your browser.

Preview how your page will appear in Google search results and social share cards on Facebook, Twitter/X, and LinkedIn. Parses <title>, meta description, canonical, and full Open Graph / Twitter Card tags with diagnostics. 100% local.

Minify HTML by removing comments, collapsing whitespace, and stripping optional attribute quotes and void-element slashes. Reports byte savings. Preserves IE conditional comments and preformatted <pre> / <textarea> / <script> / <style> content. 100% local.

Generate random UUIDs (v4) and time-ordered UUIDs (v7) online. Bulk generate up to 1000 at once and copy with one click.

Generate UUID v7 identifiers online (RFC 9562). The first 48 bits encode a Unix millisecond timestamp, so v7 UUIDs sort lexicographically by creation time — dramatically better as a database primary key than v4. Bulk generate up to 1000 and inspect the embedded timestamp for each. 100% local.

Generate NanoID strings online — 21 characters, URL-safe alphabet (a-Z, 0-9, -, _), same collision safety as UUID v4 in 40% less space. Bulk generate up to 1000 with custom length. 100% local.

Generate ULID (Universally Unique Lexicographically Sortable Identifier) strings — 26 characters, 48-bit millisecond timestamp + 80-bit randomness, Crockford Base32. Bulk generate up to 1000. 100% local.

Generate CUID2 strings online — a modern, secure, collision-resistant ID format designed for horizontal scale and safe use in URLs, cookies, and databases. 100% local, no dependencies.

Generate Twitter Snowflake IDs online — 64-bit integers with 41-bit timestamp, 10-bit worker ID, 12-bit sequence. Preview and inspect how Snowflake IDs are structured. 100% local.

Split long text into overlapping chunks for embedding and RAG pipelines. Preview recursive, paragraph, sentence, or fixed strategies with live token counts. Runs 100% in your browser.

Compute cosine similarity, dot product, and Euclidean distance between two vectors online. Perfect for debugging LLM embeddings, semantic search, and RAG pipelines. 100% local — vectors never leave your browser.

Estimate monthly LLM API cost across GPT-4o, Claude 3.5, Gemini, DeepSeek and 100+ models. Compare providers side-by-side with prompt-caching and batch discounts. Free, no signup — prices refreshed daily from the public LiteLLM catalog.

Count tokens in your prompt for GPT-4, GPT-3.5, Claude, and Gemini and predict API cost before you spend. Free, no signup — all counting runs locally, your prompt stays in your browser.

Extract every JSON object or array buried inside an LLM reply — even when it's wrapped in markdown fences, mixed with explanation text, or has trailing commas and single quotes. Auto-repairs each block. 100% local.

Check whether your prompt fits a model's context window before you send it. Estimates prompt tokens, reserves room for the response, and shows remaining headroom across GPT-4o, o1, Claude, Gemini, DeepSeek and more. 100% local.

Convert Unix timestamps to human-readable dates and vice versa. Supports seconds, milliseconds, ISO 8601, and every timezone. Free, no signup, runs entirely in your browser.

Convert any date and time between IANA time zones — UTC to EST, PST to Tokyo, Sydney to London. Correct DST handling, compare multiple zones side-by-side. 100% local.

Count business (working) days between two dates. Customize your workweek (M-F, M-Sat, custom) and paste a list of holidays to exclude them. Also shows total days, weekend days, and calendar span. 100% local.

Calculate your exact age in years, months, and days from a date of birth. Shows total weeks, days, hours, and minutes lived, plus the countdown to your next birthday. 100% local — nothing uploaded.

Calculate the exact duration between two dates in years, months, and days, plus total weeks / days / hours / minutes and business days. Optional time-of-day precision. 100% local.

Build cron expressions from a friendly UI — every N minutes, daily at HH:MM, weekdays only, weekly, monthly, yearly. Preview the next 5 runs and a plain-English description. 100% local.

Parse ISO 8601 duration strings (P3Y6M4DT12H30M5S, PT1H30M, P2W) into human-readable form, or convert total seconds into a canonical ISO 8601 duration. 100% local — used by REST APIs, video metadata, and scheduling systems.

Parse and explain cron expressions in plain English. See the next 5 upcoming run times for any schedule.

Test regular expressions online with live match highlighting, capture-group and named-group output, and every JavaScript flag (g, i, m, s, u, y). Free, no signup, no ads — runs entirely in your browser.

Find and replace text with a regular expression online. Supports every JavaScript flag (g, i, m, s, u, y), all backreferences ($1..$9, $&, $`, $', $<name>), and escape sequences (\n, \t) in the replacement. Live match-by-match preview and diff. 100% local.

Convert text to spoken audio using your browser's built-in Speech Synthesis API. Pick from all voices installed on your OS, adjust rate, pitch, and volume. No account, no download, no upload — 100% local.

Format, beautify, and validate XML documents online. Handles namespaces, CDATA sections, and mixed content.

Format and beautify SQL queries. Supports SELECT, JOIN, subqueries, CTEs, and multiple SQL dialects.

Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case, and more.

View PDF metadata online: title, author, subject, producer, creation date, PDF version, page count, encryption status. 100% local — your PDF never leaves your browser.

Count the pages in a PDF instantly, right in your browser. Drop one or many PDFs, get a total — no uploads, no sign-up, no size limit beyond your device's memory.

Extract text from any digital PDF in seconds — copy to clipboard or download as .txt. 100% client-side: no upload, no watermark, no size cap.

Merge two or more PDF files into a single document, right in your browser. Reorder pages before combining. 100% local — no upload, no watermark, no sign-up.

Split a PDF by page range, into fixed-size chunks, or into one file per page. Runs entirely in your browser — nothing is uploaded and there is no size cap.

Delete specific pages from a PDF: single pages, ranges, or 'last'. 100% local — no upload. Get a trimmed PDF with the surviving pages in original order.

Rotate all pages or a selected range by 90°, 180°, or 270°. Fixes sideways scans and portrait/landscape mixes. Runs entirely in your browser — no upload.

Convert one or many images (JPG, PNG, WebP, GIF, BMP) into a single PDF. Reorder, pick page size (A4, Letter, or auto), and download. 100% local — no upload.

Convert each page of a PDF to a PNG or JPG image at your chosen DPI (72–300). Download every page in a single ZIP. Runs locally in your browser.

Strip owner-password restrictions (print / copy / edit locks) from a PDF you own. Runs entirely in your browser — the file and password never leave your device.

View EXIF metadata in JPEG, HEIC, TIFF, and PNG photos: camera model, GPS coordinates, exact timestamps, and more. Runs entirely in your browser — nothing is uploaded.

Remove EXIF, GPS, and other metadata from your photos before sharing. Two modes: precise (lossless JPEG) or full re-encode (any format). 100% local — the photo never leaves your device.

Convert PNG images to JPG in your browser. Adjustable quality, custom background color for transparent PNGs, batch download. 100% local — nothing is uploaded.

Convert JPG images to PNG in your browser. Lossless output — no re-compression artifacts. Batch download supported. 100% local.

Convert WebP images to JPG in your browser. Great for legacy tools and platforms that don't accept WebP. 100% local, batch supported, adjustable quality.

Convert WebP images to PNG in your browser without losing more quality than the WebP already had. Preserves transparency. 100% local.