Test and validate API keys for OpenAI, Anthropic, Google AI, and other services. Secure validation without storing keys on our servers.
AWS cron expression validator for EventBridge rules and Scheduler. Explains each field and lists next run times in UTC or any time zone, with DST skips shown.
Certificate key matcher that checks whether an SSL certificate or CSR matches its private key. RSA, EC and Ed25519 PEM keys, compared in your browser. Free.
CODEOWNERS tester shows which GitHub code owner reviews each file path and which line decided. Flags invalid owners and unsupported syntax. Free, offline.
Check color contrast ratios for WCAG 2.1 accessibility compliance. Validate AA and AAA requirements for text and UI components.
Validate credit card numbers using the Luhn algorithm. Detect card types including Visa, Mastercard, American Express, Discover, and more.
Crontab tester that checks whether a cron expression fires at a given date and time, and shows which field blocked it when it does not. Free.
CSS selector tester matches your selector against pasted HTML and highlights every element it selects instantly. Debug selectors before shipping. Free, browser-based, no signup.
CSV validator that checks delimiter consistency, ragged rows, duplicate headers, and encoding issues before you import the file. Paste or upload, free.
DNS zone file validator that checks BIND records for syntax errors, bad TTLs, missing SOA fields and unterminated names. Runs offline. Free.
Dockerfile linter checks your Dockerfile for best-practice violations and security issues with line-level findings, a score out of 10, and fix hints. Free, browser-based.
Validate your .env file for naming convention errors, duplicate keys, invalid values, and formatting issues. Get line-by-line feedback instantly. Free, browser-based.
Validate email addresses instantly with format checking, domain verification, and common typo detection. Check single or bulk emails for deliverability.
Test file paths against your .gitignore rules and see exactly which pattern matched, on which line, and whether a negation won. Free, runs offline.
Generate Strict-Transport-Security (HSTS) headers with includeSubDomains and preload directives. Enforce HTTPS for your domain easily.
HTML accessibility checker that scans pasted markup for WCAG 2.2 failures: missing alt text, unlabeled form fields, skipped headings, and broken ARIA. Free, no signup.
Validate IBAN numbers instantly with country-specific length checks, formatting, and MOD-97 checksum verification for international bank accounts.
Validate JavaScript syntax instantly in your browser with a real parser. Catch syntax errors with exact line and column numbers, check module or script code, and see statement stats. Free, no signup.
Validate JSON documents against JSON Schema to catch missing fields, type errors, and invalid values - free, no install needed.
Validate JSON data instantly with detailed error messages, line numbers, and auto-fix suggestions. Lint, format, and check JSON syntax online for free.
Verify JWT signatures online using a secret or public key for HS256, HS384, HS512, and RS256 tokens. Instantly confirm validity and expiry. Free, client-side tool.
Kubernetes manifest linter checks your K8s YAML for missing resource limits, latest image tags, missing probes, and root containers. Free, instant, client-side.
Check Lua syntax instantly in your browser. Detect unbalanced blocks, unmatched brackets, and unterminated strings or comments with line numbers. Free heuristic Lua syntax validator, no signup required.
NACHA file parser and ACH file validator. Checks routing check digits, entry hash, batch totals and 94-character records, then exports entries to CSV. Free.
Nginx location tester matches any request URI against your location blocks and shows which one nginx picks, and why, using real precedence rules.
Check if a password appears in known breach data using a privacy-preserving hash prefix lookup. Your plaintext password is never sent to the server.
Analyze password strength and security in real-time. Get detailed feedback on complexity, entropy, estimated crack time, and suggestions for improvement.
Test regular expressions with real-time validation, match highlighting, and detailed explanations. Debug regex patterns quickly and efficiently.
Generate a security.txt file for vulnerability disclosure following RFC 9116. Add contact, encryption, and policy fields, then download it for your .well-known folder.
Generate SHA-256 checksums for files in your browser to verify downloads, releases, and file integrity without uploading data.
Verify webhook signatures from Stripe, GitHub, Shopify, or any HMAC provider by recomputing the hash from your payload and secret, fully in your browser.
Validate XML documents for well-formedness and syntax errors. Get instant feedback with line numbers, error details, and document statistics. Free online XML checker.
Test and evaluate XPath expressions against XML documents. Get instant results with syntax highlighting, matched nodes, and error feedback.
Validate YAML syntax instantly with detailed error messages and line numbers. Check Kubernetes manifests, Docker Compose files, CI/CD configs, and any YAML document for correctness.
Write and test Zod validation schemas directly in your browser. Paste JSON data, see live field-level error messages and parsed output. Supports the full Zod v3 API. No install required.