feat: add domainfree — bulk domain availability from RDAP

[ralyodio]

Adds bin/domainfree — bulk domain availability, straight from the registry.

Came out of naming the sorrycheck / sinkstate projects, where the DNS approach quietly gave wrong answers.

Why not DNS

DNS cannot tell registration apart from configuration:

• a parked domain resolves fine and is taken
• a domain registered with no nameservers returns NXDOMAIN — identical to a name nobody owns

Measured over 8,513 generated candidates, dig NAME | grep "ANSWER: 0" reported 20 registered domains as free, and missed none that were genuinely free.

The clearest case is oubliette.com: registered in 1996, paid through 2034, three nameservers, no A record. dig returns ANSWER: 0 and it reads as available.

So DNS is fine as a cheap prefilter and wrong as a buy signal. domainfree reads RDAP instead.

Usage

domainfree sorrycheck.com sinkstate.com
domainfree -f candidates.txt
generate-names | domainfree --jobs 24
domainfree --all example.com        # show TAKEN rows too

Only available names go to stdout, one per line; the summary goes to stderr, so domainfree -f in.txt | wc -l counts what you can buy.

Details

• Per-TLD routing: Verisign for .com/.net, PIR for .org, rdap.org for the rest.
• 16 parallel lookups by default — 8,513 names in ~47s, no rate limiting observed.
• Indeterminate results (429, 5xx, timeout) are retried once serially, then reported as ERR:<code> with exit status 2, so an unknown is never silently read as available.
• Only dependency is curl.

Complements domainjson, which does a deep lookup of one name; this answers one question across thousands.

Tested

Args, stdin, -f, --all, non-.com routing, case/whitespace normalisation, junk filtering, --help and bad-flag exit codes, plus a full 8,513-name run.

Note per the repo's own README: ~/.local/bin symlinks into the working tree, so merging this does not update the installed command — git -C ~/scripts pull after merge. I've already linked ~/.local/bin/domainfree locally.

🤖 Generated with Claude Code

[ralyodio]

Superseded by profullstack/cli-tools#8, merged and shipped in v0.2.0.

cli-tools is where the CLI tools are migrating (domainjson, blog-post, gh-prs*, tcfeed are all there already), it exposes the tool to moshcode as a domain plugin, and it has vitest coverage. Keeping a second bash implementation here would only drift.

Closing unmerged rather than resolving the README conflict.