Free hosting & developer tools

Look up A, AAAA, CNAME, MX, TXT, NS and more for any domain, instantly.

See whether your DNS change has reached resolvers around the world.

Find the hostname behind an IP address using a PTR lookup.

Look up domain or IP registration details via modern RDAP.

Validate your email DNS records and fix deliverability problems.

Check whether an IP is listed on major email blacklists.

Work out network, broadcast, usable range and host count for any CIDR.

Find the location, ISP and ASN behind any IP — or your own.

Check whether a port is open on any host from our server.

Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes in your browser.

Create strong, random passwords with a strength estimate.

Inspect any site's TLS certificate: issuer, dates, days left and SANs.

Generate random UUID v4s in bulk, ready to copy or download.

Encode and decode Base64 text safely in your browser.

Decode a JSON Web Token's header and payload without verifying it.

Convert Unix timestamps to dates and back, in UTC and local time.

Build and understand cron schedules with a plain-English summary.

Percent-encode or decode URLs and query strings correctly.

Test JavaScript regular expressions with matches, indices and groups.

Generate favicon and app-icon markup plus a preview from any image or emoji.

Look up the correct Content-Type for any file extension.

Look up what any HTTP status code means and what to do about it.

Inspect response headers, security headers and the full redirect chain.

See every hop in a redirect chain and why it matters for SEO.

Generate placeholder text by paragraph, sentence or word count.

Build a clean, table-based HTML signature that works everywhere.

Preview how your link renders on social and messaging apps.

Compress and resize images in your browser — nothing is uploaded.

Generate Apache redirect and canonical rules you can paste in.

Generate an nginx server block with HTTPS, Let's Encrypt and proxy support.