Online tools that just work

A growing set of small, focused tech tools. Pick one below.

Flash NerdMiner v2 firmware to ~30 ESP32 boards from your browser — mirrored, SHA-256 verifiable.

See your public IP address and network info — plus a simple JSON API.

Create QR codes for links, text, wifi and more.

Inspect any domain's DNS — A, AAAA, MX, TXT, NS, CAA — with TTLs, DNSSEC and a Cloudflare/Google/Quad9 comparison.

Generate and verify SHA-256, SHA-512, SHA-1, MD5 and CRC32 for text or files — entirely in your browser.

Calculate an IPv4 subnet — network, broadcast, mask, host range, counts, binary and class — and split it into smaller subnets.

Explain any cron expression in plain language, see the next runs in your timezone, and start from presets for Linux, Kubernetes and GitHub Actions.

Convert between Unix time, ISO 8601 and human dates — paste any timestamp or date and get every representation, in any timezone.

Paste a Bitcoin address to see its type (P2PKH, P2SH, SegWit, Taproot), network and encoding — validated locally.

Decode a BOLT11 Lightning invoice — amount, description, payment hash, expiry and node — locally.

Decode a JWT — header, payload, signature and claim timestamps — locally, without verifying the signature.