Developer Tools
Free developer tools — format JSON, minify CSS/JS, debug regex, encode/decode, and more. All processing happens in your browser.
About Developer Tools
Developer tools for formatting JSON, testing regex, debugging JWTs, parsing cron, encoding Base64, and 240+ more — every tool runs locally in your browser with zero uploads. Paste unformatted code, validate an API response, or generate a UUID without opening a terminal or trusting a random pastebin.
JSON Formatter
Pretty-prints raw JSON with configurable indent width, key sorting, and bracket collapsing options while flagging syntax errors with exact.
HTML Formatter
Indents and structures HTML markup with proper nesting, attribute alignment, and readable indentation for templates and email designs.
TypeScript Formatter
Format TypeScript with correct indentation, type-annotation spacing, and interface alignment. Clean up 500-line components before review — local processing, free, no signup.
SCSS Formatter
Format SCSS with nested-rule indentation, variable alignment, and mixin spacing. Tidy sprawling stylesheets before merging — local processing, free, no signup.
XML Formatter
Pretty-prints XML documents with proper tree indentation, validates structure, and reorganizes attributes for maximum readability.
Swift Formatter
Format Swift with proper indentation, optional chaining spacing, and closure layout. Clean iOS sources before commit — local processing, free, no signup.
Proto Schema Converter
Convert Protocol Buffer .proto definitions to JSON Schema and back — bridge gRPC APIs and JSON tooling for docs, validators, and gRPC tests.
tsconfig Analyzer
Audit tsconfig.json for strictness gaps, misconfigured paths, and target mismatches. Catch lax strictNullChecks before production does — local analysis, free, no signup.
Bulk Regex Extractor & Replacer
Hunt IPs, API keys, emails, and URLs across thousands of logs or code files — extract matches or replace in place. SREs scrub 5,000 logs before sharing — local JS RegExp, 2 free batches a day.
Trailing Space Remover
Strip trailing whitespace and normalize final newlines across pasted code or text. Ship zero-whitespace diffs every commit — local processing, free, no signup.
SQL Formatter
Formats SQL queries with proper keyword capitalization, indentation, and clause alignment for readable database operations.
Code Beautifier & Minifier
Beautify or minify HTML, CSS, JavaScript, XML, ERB, LESS, and SCSS with a single click. HTML, CSS, JS, XML, and more normalize in one pass — local processing, free, no signup.
Code Formatter
Auto-detect language and format mixed code snippets — JS, CSS, HTML, JSON in one paste. Clean Stack Overflow answers before using — local processing, free, no signup.
CSS Formatter
Organizes CSS stylesheets with consistent indentation, property grouping, and selector formatting for maintainable styles.
JavaScript Formatter
Format JavaScript with consistent indentation, semicolons, quotes, and brace style. Standardize legacy scripts before refactor — local processing, free, no signup.
JSX Formatter
Format JSX with component indentation, prop alignment, and expression-container spacing. Read nested component trees at a glance — local processing, free, no signup.
TSX Formatter
Format TSX React components with type-aware indentation — TypeScript types plus JSX markup, both handled correctly without breaking either side.
Python Formatter
Formats Python code with PEP 8 compliant indentation, consistent spacing, and readable structure for scripts and modules.
YAML Formatter
Structures YAML configuration files with consistent indentation, proper key alignment, and readable hierarchy for Docker and CI/CD configs.
Markdown Formatter
Format Markdown with consistent headings, lists, code fences, and table alignment. Make READMEs render perfectly on GitHub — local processing, free, no signup.
C++ Formatter
Format C++ with brace style, pointer alignment, and include ordering. Tame legacy codebases before review — local processing, free, no signup.
Go Formatter
Format Go with gofmt-compatible indentation, import grouping, and alignment. Keep goroutines readable across the repo — local processing, free, no signup.
Kotlin Formatter
Format Kotlin with indentation, null-safety spacing, and data-class layout. Clean Android sources consistently — local processing, free, no signup.
PHP Beautifier
Beautify PHP with PSR-12 indentation, spacing, and brace placement. Modernize legacy templates safely — local processing, free, no signup.
Ruby Formatter
Format Ruby with end alignment, block style, and hash syntax consistency. Unify Rails codebases effortlessly — local processing, free, no signup.
Rust Formatter
Format Rust with rustfmt-style indentation, match-arm layout, and trait organization. Keep ownership code readable — local processing, free, no signup.
CSS Generator
Generate CSS code interactively for box shadows, gradients, border radius, transforms, filters, and more. Code never leaves your device — formatting and validation run locally in your browser.
Media Query Generator
Generate CSS media queries with min/max width and optional device type conditions. Mobile-first breakpoints with device conditions — free, local, no signup.
API Request Builder
Build HTTP requests with method, URL, headers, and body — then generate matching curl commands. Prototype endpoints without leaving the tab — local, free, no signup.
API Tester
Test any HTTP endpoint by sending GET, POST, PUT, or DELETE requests directly from your browser. View response status, headers, and body.
API Response Formatter
Prettify raw JSON and XML API responses with indentation, key sorting, and syntax validation. Read nested payloads at a glance — local processing, free, no signup.
API Error Decoder
Decode cryptic API error codes into plain explanations — 4xx client errors, 5xx server faults, and retry guidance. Runs locally in your browser.
API Payload Analyzer
Inspect JSON API payloads for structure, size breakdown, and key depth — spot sensitive fields before sharing logs before production incidents.
API Mock Data Generator
Generate realistic mock JSON from field specs — names, emails, dates, nested objects. Fill frontends before backends exist — local generation, free, no signup.
API Mock Server Config
Generate JSON Server configuration files from endpoint definitions. Set up a fully functional mock API server in seconds.
Mock API Response Generator
Craft canned API responses with status codes, headers, and bodies for testing error paths. Simulate 404s and 500s without a server — local, free, no signup.
API Latency Budget
Calculate API latency budgets from SLA requirements. Distribute response time across application, database, and external service layers.
API Pagination Calculator
Calculate API pagination math — page counts, edge items, and rate-budget tradeoffs for cursor vs offset designs before you write code.
API Key Generator
Generate secure API keys with configurable length, character set, and optional prefix. Use with any authentication scheme.
API Key Hasher
Hash API keys using SHA-256 for secure storage. Never store raw API keys — hash them before persisting to your database.
API Key Validator
Validate API key format and structure — charset, length, and provider prefix patterns checked instantly without exposing secrets anywhere.
API Cost Estimator
Estimate API bills from request volumes and price-per-million — OpenAI and Stripe presets included. Forecast a 1M-request month before committing — local math, free, no signup.
API Gateway Rate Calculator
Calculate rate limits, burst capacities, and throttling thresholds for API gateway configurations. Plan your traffic management strategy.
API Rate Limiter Calculator
Calculate rate limit windows, burst allowances, and retry intervals. Design effective rate limiting for your API endpoints.
API Changelog Generator
Generate structured changelogs from API version diffs. Categorize changes as Added, Changed, Deprecated, Removed, Fixed, or Security.
API Documentation Generator
Turn endpoint descriptions into clean API docs with parameters, responses, and curl samples. Document as you build, not after — local generation, free, no signup.
REST Endpoint Documenter
Document REST API endpoints with method, path, and description. Generates formatted documentation with sample request and response bodies.
GraphQL Cost Estimator
Estimate GraphQL query complexity based on field count and nesting depth. Identify expensive queries before they hit your server.
GraphQL Query Formatter
Format GraphQL queries with consistent indentation — fragments, variables, and nested selections normalized for readable, reviewable APIs.
GraphQL Schema to JSON Schema
Convert GraphQL schema definitions to JSON Schema format. Bridge the gap between GraphQL and REST tooling ecosystems. Types map with validation preserved — free, local, no signup.
GraphQL Schema Validator
Validate GraphQL schema syntax and structure. Detect missing root types, unknown type references, and common schema issues.
GraphQL Subscription Builder
Build GraphQL subscription queries with custom event names and payload fields. Generate ready-to-use subscription strings.
GraphQL Tester
Test GraphQL queries with variables. Format queries and variables, and preview formatted responses for development and debugging.
GraphQL Variables Formatter
Format GraphQL variables JSON with validation against query structure. Stop malformed-variables errors before sending — local processing, free, no signup.
gRPC Status Code Lookup
Look up all 17 gRPC status codes (0–16) with meanings — from OK and CANCELLED through resource and network errors for backend debugging.
SOAP API Tester
Build and test SOAP API envelopes with WSDL URL, method name, and XML parameters. Generate complete SOAP request envelopes.
OpenAPI Mock Generator
Generate mock endpoints from OpenAPI specs — example responses shaped for immediate frontend work, no backend wait while real backends are still being built.
OpenAPI to Postman
Convert OpenAPI specs into Postman collections with requests, auth, and examples. Import 50 endpoints in one click — local conversion, free, no signup.
OpenAPI Validator
Basic structural check for OpenAPI/Swagger specs — required top-level fields, non-empty paths, and $ref presence. A heuristic screen, not a full spec validation: passing here does not guarantee a valid spec.
Postman Collection Generator
Generate Postman collection JSON from endpoint descriptions. Create ready-to-import collections with method and path for each endpoint.
Postman to OpenAPI Converter
Convert Postman collections to OpenAPI 3.0 specs. Migrate your API documentation. Code never leaves your device — formatting and validation run locally in your browser.
Swagger/OpenAPI Generator
Generate Swagger UI / OpenAPI specs from a simple description. Enter title, version, and endpoints to produce a complete spec JSON.
OpenAPI Documentation Generator
Generate Markdown API documentation from OpenAPI specs with endpoints and examples. Publish clean reference docs fast — local conversion, free, no signup.
API Diff Checker
Compare two OpenAPI specs side-by-side to detect breaking changes, new endpoints, removed fields, and modified schemas between versions.
Webhook Payload Generator
Generate realistic webhook payload examples with customizable event names and data fields. Test your webhook handlers with realistic data.
Webhook Retry Config
Design webhook retry policies — attempts, backoff curves, dead-letter thresholds. Stop losing events to blips — local planning, free, no signup.
Webhook Signature Verifier
Verify webhook HMAC signatures to prove payloads came from the provider untampered. Reject forged events before processing — local crypto, free, no signup.
Webhook Tester
Test webhook endpoints by sending simulated POST requests with custom JSON payloads. Verify your webhook handlers are working correctly.
Webhook Validator
Validate webhook payload structure including required fields (id, event, data, created). Ensure your webhooks meet the standard format.
Code to cURL Converter
Convert fetch, XHR, and HTTP client snippets to equivalent curl commands — headers and auth preserved for terminal debugging sessions.
cURL to Code Converter
Convert curl commands to Fetch, Axios, Python, and Go snippets instantly. Move terminal wins into codebases — local conversion, free, no signup.
JSON-RPC Builder
Build JSON-RPC 2.0 request envelopes with method, params, and IDs. Talk to Ethereum nodes and RPC APIs correctly — local building, free, no signup.
API Builder & Tester
Send HTTP requests from your browser — custom headers, bodies, params, saved collections, and one-click cURL/Fetch/Axios snippets. Developers debug a REST endpoint without leaving the tab — runs locally, free to start.
HTTP Headers Generator
Generate common HTTP headers for JSON, REST, and GraphQL APIs with correct Content-Type and authorization patterns. Code never leaves your device — formatting and validation run locally in your browser.
HTTP Status Code Checker
Look up HTTP status codes by number — view description, label, and response class (informational, success, redirect, client error, server error).
Pricing Tier Builder
Design SaaS pricing tiers with feature matrices and monthly/annual math. Model Starter/Growth/Scale before committing — local planning, free, no signup.
Password Entropy Calculator
Calculate password entropy in bits to measure password strength against brute-force attacks. Code never leaves your device — formatting and validation run locally in your browser.
Two-Factor Auth Generator
Generate TOTP URIs for two-factor authentication setup with authenticator apps. Code never leaves your device — formatting and validation run locally in your browser.
Brute Force Time Estimator
Estimate password crack times from length, charset, and attacker speed — entropy made visceral. Show why 8-char passwords fall in hours — local math, free, no signup.
Hash Verifier
Verify that a hash matches a given input to check data integrity. Code never leaves your device — formatting and validation run locally in your browser.
Hash Password Generator
Generate password hashes using PBKDF2-SHA256 with 600,000 iterations for secure password storage. Code never leaves your device — formatting and validation run locally in your browser.
Content Hash Generator
Compute SHA-1, SHA-256, SHA-384, or SHA-512 hashes of text content using the Web Crypto API. Code never leaves your device — formatting and validation run locally in your browser.
HMAC Generator
Generate HMAC signatures using a secret key and hash algorithm for API authentication. Code never leaves your device — formatting and validation run locally in your browser.
MD5 & SHA Hash Generator
Compute MD5, SHA-1, SHA-256, and SHA-512 hashes from text or file input using CryptoJS. Paste text or drop files; digests compute instantly for checksums and lookups — free, local, no signup.
SSL/TLS Checker
Check a host over HTTPS from your browser — SSL/TLS reachability (which proves the browser validated the certificate chain) plus public issuance history (issuer, expiry, cert count) via crt.sh. No cipher-suite or protocol-version scan: browsers do not expose handshakes.
HTTP Security Checker
Run an HTTP security probe on a live URL — reachability, redirect chain, and visible response details, plus a reference checklist for HSTS, X-Frame-Options, and CSP.
JWT Inspector
Decode JWT headers and payloads instantly — inspect claims, expiry, and algorithm before trusting a token. Debug auth failures in seconds — local processing, free, no signup.
Content Security Policy Generator
Build a Content Security Policy header by selecting directives and allowed sources. Code never leaves your device — formatting and validation run locally in your browser.
Subnet Calculator
Compute subnet masks, network/broadcast addresses, and usable host ranges from any CIDR. Plan a /24 office network correctly — local math, free, no signup.
Subnet Visualizer
See any CIDR as binary maps — IP, mask, and network bits plus a 32-block network/host bar. Single-network rendering only, no sub-subnetting — local rendering, free, no signup.
IPv4 Address Converter
Convert IPv4 addresses between dotted-decimal, hex, integer, and binary forms. Decode 2130706433 to 127.0.0.1 instantly — local math, free, no signup.
IP Range Expander
Expand an IP address range into a list of individual addresses. Useful for network planning and firewall rules. Code never leaves your device — formatting and validation run locally in your browser.
IPv6 ULA Generator
Generate Unique Local Addresses for private IPv6 networks — random 40-bit global IDs in fc00::/7 space, no coordination needed.
DNS Lookup Generator
Look up live A, AAAA, CNAME, MX, TXT, and NS records via DNS-over-HTTPS. Queries go to Google DNS — results display here.
CORS Inspector
Run a real CORS preflight from your browser — a cross-origin request that shows whether an endpoint allows it, with the exact server headers to confirm.
CORS Header Generator
Generate correct CORS headers — Access-Control-Allow-Origin, methods, headers, credentials. Fix preflight failures with exact syntax — local generation, free, no signup.
Env File Generator
Generate .env file templates with configurable variable names and default values. Code never leaves your device — formatting and validation run locally in your browser.
Env File Parser
Parse .env files — quoted values and comments handled, one variable per line. Local parsing, free, no signup.
CVE Lookup
Look up CVE vulnerabilities by ID with severity, descriptions, and affected products. Check CVE-2024-3094 before patching decisions — live OSV data, free, no signup.
SQL Injection Detector
Scan inputs and queries for SQL injection patterns — tautologies, unions, stacked queries. Catch ' OR '1'='1 before attackers do — local pattern matching, free, no signup.
XSS Protection Checker
Check pasted response headers for XSS-relevant protections — Content-Security-Policy, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, and X-XSS-Protection presence, locally in your browser.
CSRF Token Generator
Generate cryptographically secure CSRF tokens as hex with configurable byte length (16–128). Code never leaves your device — generation runs locally in your browser.
OAuth2 Debugger
Debug OAuth2 flows step by step — authorize URLs, code exchange, token inspection. Fix redirect_uri_mismatch in minutes — local tooling, free, no signup.
SAML Decoder
Decode and inspect SAML assertions and responses for SSO troubleshooting. Code never leaves your device — formatting and validation run locally in your browser.
CSP Policy Validator
Validate Content Security Policy headers against W3C spec and common pitfalls. Code never leaves your device — formatting and validation run locally in your browser.
TLS Cipher Checker
Look up any TLS cipher suite name — TLS_AES_256_GCM_SHA384, TLS_RSA_WITH_RC4_128_SHA — and get its strength rating from Strong to Insecure, with the reason in plain words.
IP Reputation Checker
Look up IP geolocation context — city, region, country, hostname, and ASN/org via ipinfo.io. No blocklist verdicts: abuse and blacklist checks are honest link-outs to AbuseIPDB and VirusTotal. Queried IPs leave the browser by design — live lookup, free, no signup.
URL Sanitizer
Strip tracking parameters (UTM, fbclid, gclid, and 15+ more) from URLs. Local processing, free, no signup.
SSL Certificate Decoder
Decode and view SSL certificate details including subject, issuer, and validity period. Code never leaves your device — formatting and validation run locally in your browser.
Subdomain Finder
Discover subdomains via public certificate records plus live DNS checks of common names. Read-only lookups run from your browser — the domain you check is visible to crt.sh and Google DNS, as with any lookup.
Email Validator
Validate email address format locally — regex shape, @ presence, domain TLD, and length/dot rules with named issues. No disposable-domain or MX checks. Code never leaves your device.
AES Encrypt
Encrypt text using AES symmetric encryption with a passphrase. Generate ciphertext that can be safely transmitted or stored. Code never leaves your device — formatting and validation run locally in your browser.
RSA Key Pair Generator
Generate RSA key pairs (2048/4096-bit) using the Web Crypto API. Export public and private keys as PEM strings. All client-side, no server uploads.
OAuth Client Setup
Generate OAuth authorization URLs for Google, GitHub, Facebook, Microsoft, and LinkedIn with custom client ID, redirect URI, and scope.
PKCE Verifier
Generate PKCE code_verifier and code_challenge (S256) pairs, or verify that a verifier matches a challenge. Test mobile and SPA auth flows safely — free, local, no signup.
OAuth Scope Builder
Build OAuth scope strings from comma-separated values with URL encoding and breakdown. Space-delimited scopes with encoding handled — free, local, no signup.
OAuth State Validator
Validate OAuth state parameters for format, length, and age — catch CSRF holes before they ship. Nothing leaves your browser.
PBKDF2 Hash Generator
Generate PBKDF2 hashes with 10,000 iterations of SHA-256 for password storage simulation. Tune iterations to hardware — slower hashes resist brute force — free, local, no signup.
Cookie Parser & Analyzer
Parse Set-Cookie headers into structured JSON, or analyze cookie security flags (Secure, HttpOnly, SameSite, expiry). Flag missing Secure, HttpOnly, and SameSite attributes — free, local, no signup.
Secret Scanner
Scan text and code for leaked secrets and credentials. Detects Stripe keys, GitHub tokens, Slack tokens, Google API keys, AWS keys, OpenAI keys, JWT tokens, private keys, and config passwords.
security.txt Generator
Generate RFC 9116 security.txt files with contact, policy, and expiry fields. Give researchers a reporting path — local generation, free, no signup.
robots.txt Validator
Validate robots.txt syntax — user-agents, allow/disallow, sitemaps, wildcards. Catch the Disallow: / that deindexed everything — local validation, free, no signup.
OAuth PKCE Generator
Generate RFC 7636 OAuth PKCE code_verifier + code_challenge (S256 method) pairs. Verifier uses 48 bytes → 64-char base64url, challenge uses SHA-256. Code never leaves your device — formatting and validation run locally in your browser.
IP Allowlist Generator
Build IP allowlist rules for firewalls, security groups, and app configs from CIDR lists. Generate AWS, Nginx, and htaccess formats — local, free, no signup.
CIDR Calculator
Convert CIDR prefixes to masks, ranges, and host counts — /8 through /32 decoded. Answer 'how many IPs in a /22' instantly — local math, free, no signup.
AWS IAM Policy Analyzer
Paste an AWS IAM policy JSON to check for wildcard resources, overly broad actions, and full admin access. Deny-by-default review with least-privilege guidance — free, local, no signup.
SSL Checker
Check SSL/TLS certificate details for any domain via public certificate APIs. View issuer, validity period, days remaining, and SANs. Expiry alerts catch outages before users do — free, no signup.
DNS Record Validator
Validate DNS records — A, MX, TXT, SPF, DKIM, DMARC syntax and coherence. Catch the missing SPF that tanks deliverability — local checks, free, no signup.
JWT Encoder & Signer
Build and sign JWTs with HS256/RS256 — headers, claims, expiry, and signature verification. Mint test tokens without backend roundtrips — local crypto, free, no signup.
Domain Availability Checker
Check a domain name across major TLDs against authoritative RDAP servers — a missing record means likely available. TLDs without RDAP fall back to a DNS heuristic. Always confirm with a registrar before purchasing.
Rate Limit Header Parser
Parse RateLimit/Limit headers — limits, remaining, reset times — from any API response. Read 429s correctly before retrying — local parsing, free, no signup.
URL Encoder / Decoder
Encode or decode URLs with percent-encoding. Swaps input/output for quick bidirectional conversion. Code never leaves your device — formatting and validation run locally in your browser.
Hex ↔ ASCII Converter
Convert between hexadecimal bytes and ASCII text. Supports custom delimiters and real-time bidirectional conversion. Code never leaves your device — formatting and validation run locally in your browser.
Base32 Encoder / Decoder
Encode text to Base32 or decode Base32 strings back — the alphabet TOTP apps and authenticator URIs use. Both directions, fully local.
Base64 to JSON Decoder
Decode Base64 strings and pretty-print JSON data — paste encoded text to see the decoded result instantly. Inspect API payloads and tokens readably — free, local, no signup.
Hex to Text Converter
Convert between hex strings and text. Code never leaves your device — formatting and validation run locally in your browser.
Diff Checker
Compares two input texts side-by-side, highlighting inserted, deleted, and changed lines with distinct background colors. Code never leaves your device — formatting and validation run locally in your browser.
Regex Tester
Provides an interactive environment where users can write a regular expression pattern, test it against sample strings, and view real-time match. Code never leaves your device — formatting and validation run locally in your browser.
Validator
Basic syntax sanity check for JSON (full parse), XML (root-element check), and YAML (real js-yaml parse) — JavaScript not included. Code never leaves your device.
YAML Validator
Validate YAML formatting, detect indentation issues, convert YAML to JSON, and minify YAML comments. Code never leaves your device — formatting and validation run locally in your browser.
Git Commit Linter
Validate git commit messages against the Conventional Commits specification. Code never leaves your device — formatting and validation run locally in your browser.
.gitignore Generator
Generate .gitignore files by selecting languages, frameworks, and tools from a checklist — covers Node, Python, Java, Go, Rust, macOS, Windows, Linux, and popular IDEs. Supports negation patterns and custom rules.
JSON Path Query Builder
Query JSON data using dot-notation path expressions with wildcard support. Code never leaves your device — formatting and validation run locally in your browser.
JSON Diff Checker
Diff two JSON documents with path-level change listing — spot breaking API changes instantly. Review a 500-line response diff in minutes — local processing, free, no signup.
JSON Tree Viewer
Visualize JSON structure as an indented tree — see nested objects and arrays at a glance. Collapse deep branches to navigate large payloads — free, local, no signup.
HTML to JSX Converter
Converts HTML files to JSX format — web pages, email templates, and content rendering to React component definitions and UI rendering. All conversion happens locally in your browser with no file size limits.
SVG to CSS Converter
Convert SVG images to CSS format in your browser. Code never leaves your device — formatting and validation run locally in your browser.
JWT Debugger
Decode and inspect JWT tokens — view header, payload, expiration, issuer, subject, and other standard claims. Paste an HMAC secret to genuinely verify HS256/384/512 signatures — local inspection, free, no signup.
HTML Preview
Write HTML and see a live preview rendered in a sandboxed iframe. Perfect for prototyping and testing. Code never leaves your device — formatting and validation run locally in your browser.
Cron Expression Parser
Parse cron expressions into human-readable descriptions. Includes common presets for quick reference. Presets plus plain-English schedules prevent 3am surprises — local parsing, free, no signup.
GeoJSON Validator
Validate GeoJSON objects against the GeoJSON specification. Checks feature, geometry, point coordinates, FeatureCollection structure, and bounding box format.
RSS Feed Validator
Validate RSS/Atom feeds for spec compliance — required fields, date formats, enclosures. Fix podcast feeds Apple rejects — local validation, free, no signup.
Sitemap Validator
Validate XML sitemaps — checks urlset/sitemapindex root, loc entries, XML declaration, and URL count. Supports standard sitemap protocol formatting.
XPath Validator
Test XPath expressions against XML documents with match highlighting. Debug //book[price>30] before committing scrapers — local evaluation, free, no signup.
Cron Expression Validator
Validate cron schedules and preview next run times — catch the Sunday-vs-7 bug before production. Verify 0 2 * * * runs 2am daily — local parsing, free, no signup.
HTML Linter
Lint HTML for missing DOCTYPE, unclosed tags, and unexpected closing tags. Paste your HTML and get instant feedback. Catch errors before browsers guess wrong — free, local, no signup.
XML Minifier / Validator
Minify XML by removing whitespace, or validate XML syntax. Paste your XML and choose an operation. Minify for transit or validate for correctness — free, local, no signup.
Character Encoding Converter
Analyze each character to see its Unicode code point and ASCII/non-ASCII status. Debug mojibake with byte-level views — free, local, no signup.
Unicode Converter
Convert text to Unicode code points with JavaScript escape sequences and HTML entities. JavaScript escapes plus HTML entities covered — free, local, no signup.
PX to REM Converter
Convert between PX and REM with custom base size. Code never leaves your device — formatting and validation run locally in your browser.
MessagePack Inspector
Decode MessagePack binary into readable JSON structures. Debug compact payloads without hex dumps — local decoding, free, no signup.
CBOR Inspector
Decode CBOR binary (RFC 7049) into readable structures — inspect IoT and WebAuthn payloads. Read COSE keys without a parser library — local decoding, free, no signup.
Avro Schema Generator
Generate Apache Avro schemas from a JSON field definition. Configure namespace, record name, and field types — outputs valid Avro schema JSON.
Avro to JSON Sample Generator
Generate sample JSON data from an Avro schema. Auto-generates values based on field types. Code never leaves your device — formatting and validation run locally in your browser.
JSON Escape/Unescape
Escape JSON strings for embedding or unescape back to readable text in one click. Fix double-escaped API fixtures fast — local processing, free, no signup.
JSON Flattener
Flatten nested JSON objects into dot-notation key-value pairs. Unwrap complex hierarchies for tabular processing. Dot-notation paths preserve nesting info for spreadsheets and logs — local processing, free, no signup.
JSON to Zod Schema
Generate Zod validation schemas from sample JSON data. TypeScript runtime validation. Code never leaves your device — formatting and validation run locally in your browser.
NDJSON to JSON Array
Convert newline-delimited JSON streams to JSON arrays for analysis. Turn 10,000 log lines into queryable data — local conversion, free, no signup.
JSONL Formatter
Format JSON Lines files with per-line pretty-printing and validation. Read streaming logs like structured data — local processing, free, no signup.
JSON to URL Parameters
Flatten JSON objects into URL query strings — nest with bracket notation. Build ?filter[x]=1 links from API objects — local conversion, free, no signup.
JSON Schema Generator
Generate JSON Schema from sample JSON — types, required fields, and nested structure inferred automatically in seconds flat.
Merge Patch Generator
Generate JSON Merge Patch (RFC 7396) documents by comparing original and modified JSON objects. Show exactly what changed.
CSS Specificity Calculator
Compute CSS selector specificity (a,b,c scores) and settle override battles with math. Prove #id beats .class chains — local calculation, free, no signup.
CSS Validator
Validate CSS syntax — unclosed braces, bad properties, bad values — with line numbers. Catch the missing } breaking layouts — local validation, free, no signup.
JSON Output Tools
All-in-one JSON output hub — format, validate, convert to Zod, URL params, flat pairs, JSON-LD, and size analysis. One tab for every JSON chore — local processing, free, no signup.
URL Parser
Parse any URL into its components — protocol, hostname, path, query parameters, hash, and more with copy-to-clipboard. Host, path, query, and fragment split with decoding — debug redirect chains precisely. Runs locally, free, no signup.
Protobuf Decoder
Decode protobuf wire format hex bytes into readable field structure. Shows field numbers, wire types, varints, strings, nested messages, and raw hex.
Query String Parser
Parse and inspect URL query parameters as structured key-value pairs. Decodes URL-encoded values and displays them in a readable JSON format.
Email Normalizer
Normalize email addresses by removing dots (Gmail), stripping +tags, and lowercasing. Process multiple emails at once for deduplication and cleaning.
JSON-LD Generator
Wrap JSON data in valid JSON-LD (Linked Data) structure with @context and @type. Generate schema.org-compatible structured data.
JSON Size Analyzer
Profile JSON payload weight — byte size, key counts, nesting depth, and heavy branches. Find the 2 MB field bloating responses — local analysis, free, no signup.
Docker Compose Validator
Validate docker-compose.yml — YAML syntax, indentation, tabs, and services presence. Catch the tab indent breaking deploys — local validation, free, no signup.
Dockerfile Linter
Lint Dockerfiles against 20+ valid instructions (FROM, RUN, CMD, COPY, ENTRYPOINT, HEALTHCHECK, SHELL). Detects unknown instructions and missing FROM declaration.
htaccess Validator
Validate .htaccess files against 30+ known Apache directives. Checks RewriteEngine, RewriteRule, ErrorDocument, Redirect, Header, Options, and block directives. Flags unknown directives.
Kubernetes YAML Validator
Validate Kubernetes manifests — apiVersion/kind, required metadata, probe and resource sanity. Catch CrashLoop configs before apply — local validation, free, no signup.
GitHub Actions Validator
Validate GitHub Actions workflow YAML — checks for workflow name, on trigger, jobs section, and correct YAML structure. Identifies formatting issues and missing fields.
Code Obfuscator
Obfuscate JavaScript with Base64 layering and reversal for casual code-sharing protection. Deter copy-paste without real crypto claims — local processing, free, no signup.
Code to cURL Parser
Parse curl commands into method, URL, headers, and body parts for debugging. Dissect a failing Stripe call field by field — local parsing, free, no signup.
JavaScript Syntax Checker
Check JavaScript code for syntax errors using the Function constructor. Validate code before execution. Code never leaves your device — formatting and validation run locally in your browser.
Pug to HTML Converter
Convert Pug/Jade templates to plain HTML for migration and debugging. Move legacy views to modern stacks — local conversion, free, no signup.
Nginx Config Generator
Generate Nginx server blocks — reverse proxy, SSL, gzip, caching headers — without syntax hunting. Ship a correct vhost first try — local generation, free, no signup.
ESLint Config Generator
Generate ESLint flat configs with curated rule sets for React, Node, and TypeScript. Standardize linting across repos — local generation, free, no signup.
Docker Run to Compose Converter
Convert docker run commands to docker-compose.yml format. Supports ports, volumes, environment variables, networks, restart policies, and container names.
HTTP Header Analyzer
Analyze HTTP request and response headers — detect security headers, review formatting, and inspect value structure. Code never leaves your device — formatting and validation run locally in your browser.
HTTP Cache Header Generator
Generate Cache-Control directives with configurable max-age, scope, must-revalidate, and no-transform options. Code never leaves your device — formatting and validation run locally in your browser.
HTTP Retry Policy Builder
Build HTTP retry policies with exponential backoff, fixed delay, or circuit breaker strategies for resilient API clients. Code never leaves your device — formatting and validation run locally in your browser.
WHOIS Lookup
Look up domain registration information using public RDAP APIs. Check registrar, expiration date, name servers, and more.
Web Inspector & HTTP Tools
Browser device info, user-agent parser, HTTP status codes reference, MIME types lookup, Basic Auth header generator, Open Graph meta tags generator, and keycode inspector.
User-Agent Parser
Parse User-Agent strings into browser, OS, device, and bot verdicts. Identify crawlers vs customers in logs — local parsing, free, no signup.
Chmod Calculator
Convert between numeric (755) and symbolic (u=rwx,g=rx,o=rx) chmod permission formats. See detailed breakdown for owner, group, and others.
IP Address Lookup
Displays your public IPv4 and IPv6 addresses with geolocation data (city, ISP, ASN, timezone). Network engineers use it to verify VPN connectivity. Uses cloud-based processing.
MAC Vendor Lookup
Look up device manufacturer from a MAC address OUI prefix against a built-in list of ~550 vendors, from Apple and Samsung to Intel and Cisco.
Random IP Generator
Generate random IPv4 and IPv6 addresses for network testing, development, and security research. Code never leaves your device — formatting and validation run locally in your browser.
Random Token Generator
Generate random tokens in hex, base64, or alphanumeric formats for secrets and sessions. Hex and base64 draw from Web Crypto (alphanumeric uses Math.random — see format notes). The API-key preset mints 64-char secrets in one click — local generation, free, no signup.
Dummy Text Generator
Generate dummy placeholder text at a specified character length for design mockups, UI prototypes, and content layout testing. Code never leaves your device — formatting and validation run locally in your browser.
Fake Identity Generator
Generate complete fake identities with name, email, phone, address, date of birth, and occupation. Includes a photo placeholder. Code never leaves your device — formatting and validation run locally in your browser.
Serial Number Generator
Generate formatted serial numbers with prefixes, segments, and checksums for products and licenses. Create 1000 trackable SKUs in one batch — local, free, no signup.
UUID Generator
Generates UUID v4 random identifiers in standard 36-character string format with an optional compact hex mode (no dashes). Code never leaves your device — formatting and validation run locally in your browser.
Test Data Generator
Generate realistic fake data — names, emails, numbers, addresses — in common formats for testing and demos for demos, seeding, and UI tests.
Open Graph Generator
Generate Open Graph and Twitter Card meta tags with image specs for perfect link previews. Fix blank Discord embeds in minutes — local generation, free, no signup.
Fake Data Generator
Generate realistic fake datasets — users, orders, addresses — for demos and load tests. Fill staging with 10k believable rows — local generation, free, no signup.
Fake Credit Card Generator
Generate fake credit card numbers with valid formats including Visa, Mastercard, Amex, and Discover. All numbers pass Luhn algorithm validation. Code never leaves your device — formatting and validation run locally in your browser.
Coupon Code Generator
Generate memorable coupon codes in bulk with prefixes and exclusions — WELCOME10-style campaigns. Create 500 trackable codes in one batch — local generation, free, no signup.
License Key Generator
Generate formatted software license keys from any X-template with dash separators. Issue random XXXX-XXXX keys for mock releases — local generation, free, no signup.
PIN Generator
Generate numeric PINs in fixed lengths (4, 5, 6, 8, or 10 digits) for everyday codes and test data. Code never leaves your device — generation runs locally in your browser.
Random User-Agent Generator
Generate random browser user-agent strings from a curated list covering Chrome, Firefox, Safari, Edge, and mobile browsers. Free to start with no signup.
Random Port Generator
Generate random TCP/UDP port numbers from well-known, registered, or dynamic ranges. Useful for network testing, Docker port mapping, and firewall configuration.
Memorable Password Generator
Generate strong yet memorable passwords — word-based passphrases with real entropy. Get correct-horse grade security you can type — local crypto, free, no signup.
String Inspector
Inspect any string — view character count, byte length, word count, line count, Unicode code points, and non-ASCII character breakdown.
QR Code Reader
Decode QR codes from uploaded images. Scan any QR code image and extract the embedded text or URL. Point it at screenshots, photos, or documents — decoded URLs and text copy out instantly. Runs locally, free, no signup.
YAML Re-indenter
Clean up messy YAML — fix indentation, align colons, and normalize list formatting. Paste any YAML and get consistently formatted output.
Conventional Commit Generator
Generate Conventional Commits messages — type, scope, breaking flags — that changelogs can parse. Write feat(api): add retry in seconds — local generation, free, no signup.
HAR File Analyzer
Analyze HAR network captures — waterfall timing, payload sizes, failed requests. Find the 3-second render blocker in minutes — local parsing, free, no signup.
package.json Validator
Validate package.json for required fields, semver format, and dependency presence. Catch missing fields and bad semver before installs fail — free, local, no signup.
Data Anonymizer
Mask PII in datasets — names, emails, phones, IDs — with consistent fake replacements. Share analytics safely under privacy rules — local processing, free, no signup.
Port Number Lookup
Look up TCP/UDP port assignments — 443 HTTPS, 5432 Postgres — with service context. Identify mystery listeners instantly — local reference, free, no signup.
SSE Event Formatter
Format Server-Sent Events streams — data, event, id, retry fields validated. Debug EventSource feeds line by line — local processing, free, no signup.
SSH Key Generator
Generate SSH key pairs (ed25519/RSA) with copy-ready public and private parts. Set up server access in a minute — local Web Crypto, free, no signup.
JWK Generator
Generate JSON Web Keys (JWK: RSA, EC, oct) with kid and alg parameters — browser-crypto randomness, ready to use for auth systems that need them.
Fluid Typography Calculator
Compute fluid clamp() type scales that flex between viewport sizes — no breakpoints needed. Set 16→20px body that just works — local math, free, no signup.
Semver Calculator
Compute next semantic versions from change types — breaking bumps major automatically. Tag v2.4.1 correctly after that breaking fix — local logic, free, no signup.
Bulk Font Subsetter
Convert TTF/OTF to WOFF2 subset to only your used characters and cut 50–200 KB fonts to 2–15 KB. Performance engineers fix the render-blocking font in one batch — local opentype.js, 2 free batches a day.
Markdown Table Generator
Generate Markdown tables without hand-aligning pipes — define columns and rows, preview live, and copy GitHub-ready markup.
Website Screenshot
Take a screenshot snapshot as a static-HTML approximation of any public page, rendered in your browser. Choose output format, viewport size, and settle delay. Page HTML is fetched via a first-party proxy, then rendered locally.
PHP Tools
Convert between JSON and PHP arrays, and serialize/unserialize PHP data. All four operations in one tool with instant swap.
SVG Optimizer
Minify SVG by removing whitespace, comments, and redundant attributes — typically cutting files 20–50% with zero visual change.
MIME Type Finder
Find MIME types for any file extension — and extensions for MIME types. Set correct Content-Type headers fast — local reference, free, no signup.
String Template Tester
Test JavaScript template literals live — ${} interpolation, nesting, and escaping, evaluated instantly with instant error highlighting.
Log File Analyzer
Analyze log files — error grouping, level counts, time clustering. Find the 3am spike cause in minutes — local parsing, free, no signup.
Phone Number Parser
Parse and validate international phone numbers for 18 built-in dial codes with automatic country detection. Returns country, code, national number, and E.164 — no area-code or carrier lookup. All validation runs locally in your browser.
Large Text File Viewer
Open multi-megabyte text files that crash editors — chunked rendering keeps scrolling smooth. Read 50 MB logs without freezing — local FileReader streaming, free, no signup.
More from Toolzum
Guides
✓ 242 dev tools — formatters, validators and encoders run locally; secrets never uploaded.
Local tools work offline after first load; AI and live lookups need a connection.
Developer FAQs
Which regex flavor does the tester use?
JavaScript (the same engine as your browser), with live match highlighting and capture-group inspection. Patterns you validate here behave identically in Node.js and frontend code.
Is it safe to paste a JWT or API key into the decoders?
Yes — decoding and validation happen entirely in your browser; nothing is transmitted. Still, prefer test tokens over production secrets out of habit.
Why is my Base64 output ~33% larger than the input?
That's inherent to the encoding: every 3 input bytes become 4 ASCII characters. Use the converter for data URIs, basic-auth headers, and embedding small assets in CSS.
How do I read a cron expression like */15 9-17 * * MON-FRI?
Field by field: every 15 minutes, hours 9–17, any day of month/month, weekdays only. The cron parser expands any expression into plain-English schedules and next-run times.