DevStudio — Offline Developer Tools
DevStudio is a free, in-browser collection of 125 developer utilities — JSON formatter, JWT decoder, regex tester, HAR analyzer, base64, hash and HMAC generators, color picker, cron builder, and dozens more — all running locally on your device. No sign-up, no installation, no upload: paste secrets, production payloads, or sensitive configuration with confidence — nothing leaves your browser tab. Pick a tool below to get started.
Build
UUID / ULID — Generate unique identifiersIdentifier Toolkit — UUID v1/v4/v5/v7, ULID, BIP39, URL-safe tokens, Basic Auth, Snowflake & UUID analyzerPassword Generator — Generate secure passwords with strength scoring & custom rulesMock Data Generator — Generate fake names, emails, addresses & more — seeded for reproducibilityLorem Ipsum — Generate placeholder text for mockups, layouts, and testingMessage Template — Generate personalized bulk messages from a template with variable column bindingsRepo Doc Generator — Generate conventional commit messages, changelogs, and READMEs from a configured workspace — AI-powered (WIN-5)QR Code Generator — Generate QR codes from text or URLs — pure browser, no librariesURL Opener — Bulk-open, extract, clean, template & analyze URLs — profiles, palette, AISticky Notes — Create, organize and manage sticky notes with color coding and time-based remindersRandom File Generator — Generate one or many random files with configurable naming, content modes, and bulk downloadsFile Splitter & Joiner — Split multiple large files into chunks and join parts back together with progress trackingFile Compressor — Compress one or many files with drag-and-drop and worker-powered progress for large filesChmod — Convert permissions between 755, rwxr-xr-x, and octal notationSemver Tool — Parse, compare, validate, and sort semantic versionsSRE Calculators — SLA uptime, error budget, bandwidth, hosting bandwidth & download-time calculatorsBenchmark Lab — Micro-benchmark JS expressions — median / p95 / p99 / stdev / ops-s plus a Welch t-test side-by-side comparisonWeb Config Generator — Emit robots.txt, sitemap.xml, .htaccess, NGINX, Apache vhost, PWA manifest, OG/Twitter meta, Schema.org JSON-LD, favicons
Inspect
String Inspector — Escape strings, visualize whitespace, and inspect Unicode code pointsMIME Type Checker — Look up MIME types by file extension or content sniffingURL Splitter — Break URLs into scheme, host, port, path, query and fragment partsUser-Agent Parser — Decode a UA string into browser / OS / device / engine; flag bots, crawlers, CLIs and library fetchersDev Cheatsheets — Searchable Vim / Git / Regex / JSON / CSS / YAML / SQL / Markdown / cron / Bash referenceForensic Extractors — Paste a log / email / packet dump and extract IPs, domains, emails, URLs, file paths, dates, hashes, UUIDs and crypto addresses — with one-click defang for safe sharingStrings & Binary Tools — Extract ASCII / UTF-8 / UTF-16 strings from a paste or dropped binary, defang or refang IOCs, and walk the buffer for embedded file signatures from the magic-number databaseJSON Schema — Infer schema and validate JSON dataJSONPath Evaluator — Evaluate JSONPath expressions against JSON data — root/child/recursive descent/filtersXPath Evaluator — Evaluate XPath expressions against XML documents — supports 1.0 syntax + namespace bindingsGraphQL Toolkit — Schema-side companion to API Client: formatter, introspection tree, AST outline, codegen (TS / TS-resolvers / Java / fragment matcher) and a point-and-click query ExplorerFile Viewer — View, search, and analyze JSON, YAML, CSV, TSV, XML, Excel, and Parquet filesCSV Analyzer — View, filter & sort CSV files.env Parser — Parse & validate .env files — detect duplicates, mask secretsIBAN / Phone Validator — Validate IBANs (mod-97 + bank/branch extraction across 80+ countries) and parse phone numbers to E.164 / international / RFC 3966ICS Viewer — Drop or paste an RFC 5545 iCalendar file and view its event grid — summary, start/end, TZ and locationDiff Viewer — Two-way & three-way text diffsMarkdown Previewer — Live side-by-side Markdown to HTML renderingRegex Tester — Test regular expressionsDisassembler — Paste hex bytes or drop a binary and disassemble across x86 / x86-64 / ARM / ARM Thumb / ARM64 / MIPS32 / MIPS64 — Intel ↔ AT&T syntax toggle, in-browser Capstone WebAssembly engineSVG Viewer — Drop or paste SVG markup and see a live preview plus declared width / height / viewBox / element-count metadata
Diagnose
Hash — Generate SHA-256 & other hashesHMAC — Generate HMAC authentication codesJWT — Decode & encode JSON Web TokensAuth Tokens — RFC 6238 TOTP / RFC 4226 HOTP generator + verifier and CSPRNG-backed OTP backup codesPGP Tool — OpenPGP keypair generation (RSA / Curve25519), sign / verify, encrypt / decrypt — interoperable with GPGHash & Crypto Lab — Deep-dive companion to Hash: BLAKE2/3, RIPEMD, Whirlpool, SHA-3 / Keccak, SM3, XXHash + bcrypt / Argon2 / scrypt / PBKDF2 + AES-GCM/CBC/CTR + ChaCha20-Poly1305 + heuristic hash identifierCertificate Inspector — Parse and inspect X.509 certificates — subject, issuer, SANs, key info, fingerprintsTLS Deep Scanner — SSL Labs-class TLS handshake inspector, vulnerability probe matrix (Heartbleed / POODLE / DROWN / Ghostcat) and rustls cipher reference + curated HSTS preload checkClassical Cipher Playground — Nine historical ciphers in one playground — Caesar, Atbash, Affine, Bifid, Vigenere (with Kasiski exam), Bacon, Enigma M3/M4, Bombe stop-finder and Lorenz SZ40 / Colossus referenceHAR Analyzer — Analyze one or more HAR filesHAR Sanitizer — Strip Authorization / Cookie / Set-Cookie headers and *token* / *key* / *password* query and form parameters from HAR files for safe sharing — all client-sidePCAP Analyzer — Inspect packet captures with Wireshark-style viewscURL Converter — Convert cURL to fetch / axios and backHeader Analyzer — Security grading, cookie audit, cache explanation & leakage detectionPing — HTTP-based ping with RTT, jitter & packet loss statsSpeed Test — Measure download, upload & latency via Cloudflare endpointsNetwork Self-Info — Public IPv4/IPv6, GeoIP, ASN, reverse DNS, port reachability & browser-fingerprint summaryOpen Port Checker — Gateway-side raw-TCP port scan with service hints — range or targeted sweep against authorized hostsBrowser Fingerprint — Navigator, screen, WebGL, font and IP introspection — all client-sideIP / CIDR — Subnet masks, host ranges & broadcast from CIDRIPv6 Shortener — Expand and shorten IPv6 addresses — RFC 5952 canonical formMAC Tools — OUI vendor lookup, random MAC generator, IPv4 range expander & IPv6 ULA prefixHTTP Status — Filterable quick-reference for HTTP response codesPort Reference — Offline lookup for well-known ports with instant searchRandom Port Generator — CSPRNG-backed port allocator over a chosen range + HTTP reachability probe — cross-references well-known portsMagic Number Browser — Searchable file-signature database — extension, MIME, hex prefix, byte offset and description for archives, documents, images, audio, video, executables, scripts, databases, disk images, fonts and crypto containersDNS Toolkit — A/AAAA/CNAME/MX/TXT/NS records, propagation across public resolvers, NS trace, reverse DNS, ASN lookupMail Diagnostics — SPF / DKIM / DMARC / BIMI / MTA-STS / TLS-RPT probes, SMTP RCPT (opt-in) and EML / header analyzerWeb Probes — Redirect trace, header dump, security audit, HTTP/2 + HTTP/3 + WebSocket sniff, URL compare and link checkerDomain Diagnostics — WHOIS, domain-expiry warning and DNSBL / RBL multi-list lookupLog Analyzer — Parse & analyze logsThread Dump — Enhanced thread dump analyzer — overview, charts, compare up to 3 dumps, deadlock detectionBrowser Heap Analyzer — Analyze browser memory snapshots (.heapsnapshot/.fxsnapshot) — dominator tree, retainers, leak detectionJava Heap Profiler — Analyze .hprof JVM dumps — class histogram, dominator tree, GC roots, instance browser (supports 16–32 GB files)Forensic Analyzers — Shannon entropy + sliding-window chart, chi-square uniformity test, byte / n-gram frequency histogram, hash-algorithm identifier and UUID field decoder — all client-sideYARA Scanner — Compile YARA rules in-browser via the @virustotal/yara-x WebAssembly engine and scan paste / hex / base64 / file samples — curated reference library included
Connect
API Client — Universal API client — REST, GraphQL, MCP, SSE — environments, collections, scripts, visualizerWebhook Receiver — Ephemeral inbox URL captures live HTTP requests; replay them against any target with header overrides; copy curl / httpie / wget snippetsDB Client — SQL database client — query, explore, and manage databases via devstudio-proxyFile Browser — Browse and manage local filesKubernetes — Kubernetes cluster explorer — pods, deployments, services, logs, events, YAML — via devstudio-proxyContainers — Container runtime explorer — Docker, Podman, containerd, CRI-O — containers, images, volumes, networks — via devstudio-proxySSH Client — SSH terminal, SFTP & port forwarding — via devstudio-proxyKafka — Apache Kafka browser — topics, messages, consumer groups, brokers, schema registry — via devstudio-proxyDocker Helper — Convert docker-run into docker-compose, build Compose services from a form, browse Docker Hub image tagsCompose / K8s Builder — Form builder for Docker Compose (multi-service) + Kubernetes manifests (Deployment / Service / Ingress / ConfigMap / Secret) with live YAML preview
Compose
Diagram Designer — Full-featured diagram editor — draw.io compatible, multi-page, layers, format panelMermaid / PlantUML — Text-DSL diagram editor with live preview — Mermaid (client-side) + PlantUML (via Kroki)Skill Maker — Create, browse, validate & download agent skills — a visual editor for the SKILL.md formatWorkflow Wizard — Universal drop surface + DAG canvas that composes the other DevStudio tools into reusable workflowsCode Navigator — Workspace-mount code explorer — file tree + Monaco editor + LSP-driven symbol-tree side panel (rust-analyzer / gopls / pyright / tsserver / clangd) via gateway-internal lsp_proxyAI Agent Runtime — Sandboxed Claude Code skill runtime — skill picker (skill-maker IDB + paste JSON) + capability allowlist + gateway-internal agent_sandbox executor + append-only tool-call event streamDevOps Debugger — CI-script Docker debugger — workspace mount + GHA / GitLab / CircleCI YAML parser + job/step tree + gateway-internal ci_replica session start (step-through + breakpoints land in WIN76)
Account
My Profile — View your Auth0 profile and reset your password