8 free tools for developers and small businesses. Generate invoices, format JSON, build cron expressions, test webhooks, and more. No signup required.
Create professional PDF invoices instantly. Fill in your details, choose a template, and download — no signup needed.
Generate itemized receipts for your business. Multiple templates, instant PDF download, completely free.
Format, validate, beautify, and minify JSON with syntax highlighting and tree view. Runs entirely in your browser.
Build, parse, and validate cron expressions with an interactive builder. Presets for common schedules included.
Calculate downtime allowances for any SLA level. See exactly how much downtime 99.9% uptime means per year, month, or week.
Plan gradual feature rollouts with traffic estimates and risk assessment. Calculate rollout stages and user exposure.
Calculate the sample size and duration needed for statistically significant A/B test results.
Create a temporary webhook endpoint instantly. Inspect headers, payloads, and response details. No signup required.
Our APIs offer programmatic access with generous free tiers. Start building in minutes.