Domain Search
Brainstorm brandable names and check which domains are actually available to register.
How availability is checked: RDAP (not WHOIS, not a paid API)
Availability is determined with RDAP — the official IETF successor to WHOIS (RFC 9082/9083).
Query https://rdap.org/domain/<fqdn>, which routes to the responsible registry and returns:
- HTTP 404 → AVAILABLE (no registration record exists)
- HTTP 200 → TAKEN (a registration record exists)
- anything else → UNKNOWN (TLD has no RDAP server)
rdap.org throttles bursts, so the script retries 429/5xx/network failures up to 3× with
backoff and pauses ~0.2s between domains (RDAP_THROTTLE env var). Without that, transient
rate-limiting shows up as UNKNOWN and quietly hides real answers in a large batch.
This is authoritative and free. It is more reliable than scraping Instant Domain Search /
GoDaddy, whose public endpoints change and rate-limit. RDAP tells you registered or not; it
does not price premium/reserved names — confirm the final price at a registrar.
Caveats (state these when relevant)
- Not all TLDs publish RDAP.
.io historically had no RDAP, and some ccTLDs still don't.
UNKNOWN means "couldn't determine" — never report it as available.
.com, .ai, .net, .org, .app, .dev, .co work well via RDAP.- An RDAP-available name can still be a premium listing (high price). Verify at checkout.
The script
scripts/check-domains.sh — batch checker. Always pass it as an explicit list (zsh does not
word-split unquoted variables, so loop over arrays or pass args directly).
# Names × TLDs (cartesian):
bash scripts/check-domains.sh --tlds com,ai,app myname otherword
# Explicit FQDNs:
bash scripts/check-domains.sh acme.com acme.ai foo.io
# Machine-readable (for further processing):
bash scripts/check-domains.sh --json --tlds com,ai myname
Output uses ✅ AVAILABLE / ❌ taken / ❓ unknown.
Workflow
- Understand the product before brainstorming. Check the repo, README, and (if present)
the user's memory/notes so names fit the actual positioning, audience, and tone.
- Brainstorm in styles, not at random — mix: real words, invented/portmanteau, foreign
words, compounds, and
verb+suffix (-ly, -ify, -ish). Short single words are almost always
taken on .com; compounds and coined words are where .com wins are found.
- Batch-check with the script across the TLDs the user cares about (default
.com,.ai).
- Present results grouped by availability, leading with names available on the user's
preferred TLD. For each, give a one-line rationale (what it evokes) so the choice is informed.
- Remind that RDAP-available ≠ final price; premium names cost more — verify at a registrar
(Cloudflare Registrar is at-cost and a good default if the user already uses Cloudflare).
Tips
- Default to checking
.com and .ai; add .app/.io/.dev for developer-facing tools.
- If the user already owns domains (e.g. registered at Cloudflare), check whether one fits
before suggesting new purchases — reusing an owned domain is free.
- Avoid names colliding with direct competitors or trademarks; flag near-misses you notice.
1---2name: domain-search3description: Check domain-name availability and brainstorm brandable names to buy. Use when the user wants to know if a domain is available/taken, find an available name for a project, compare names across TLDs (.com/.ai/.io/...), or pick a product/company/brand name. Triggers: "is X.com available", "find a domain", "check these domains", "available domain names", "name this project/product/company", "brainstorm a brand name", "domain availability".4---56# Domain Search78Brainstorm brandable names and check which domains are actually available to register.910## How availability is checked: RDAP (not WHOIS, not a paid API)1112Availability is determined with **RDAP** — the official IETF successor to WHOIS (RFC 9082/9083).13Query `https://rdap.org/domain/<fqdn>`, which routes to the responsible registry and returns:1415- **HTTP 404 → AVAILABLE** (no registration record exists)16- **HTTP 200 → TAKEN** (a registration record exists)17- **anything else → UNKNOWN** (TLD has no RDAP server)1819rdap.org throttles bursts, so the script retries `429`/`5xx`/network failures up to 3× with20backoff and pauses ~0.2s between domains (`RDAP_THROTTLE` env var). Without that, transient21rate-limiting shows up as `UNKNOWN` and quietly hides real answers in a large batch.2223This is authoritative and free. It is more reliable than scraping Instant Domain Search /24GoDaddy, whose public endpoints change and rate-limit. RDAP tells you *registered or not*; it25does **not** price premium/reserved names — confirm the final price at a registrar.2627### Caveats (state these when relevant)28- **Not all TLDs publish RDAP.** `.io` historically had no RDAP, and some ccTLDs still don't.29 `UNKNOWN` means "couldn't determine" — never report it as available.30- `.com`, `.ai`, `.net`, `.org`, `.app`, `.dev`, `.co` work well via RDAP.31- An RDAP-available name can still be a **premium** listing (high price). Verify at checkout.3233## The script3435`scripts/check-domains.sh` — batch checker. Always pass it as an explicit list (zsh does not36word-split unquoted variables, so loop over arrays or pass args directly).3738```bash39# Names × TLDs (cartesian):40bash scripts/check-domains.sh --tlds com,ai,app myname otherword4142# Explicit FQDNs:43bash scripts/check-domains.sh acme.com acme.ai foo.io4445# Machine-readable (for further processing):46bash scripts/check-domains.sh --json --tlds com,ai myname47```4849Output uses ✅ AVAILABLE / ❌ taken / ❓ unknown.5051## Workflow52531. **Understand the product** before brainstorming. Check the repo, README, and (if present)54 the user's memory/notes so names fit the actual positioning, audience, and tone.552. **Brainstorm in styles**, not at random — mix: real words, invented/portmanteau, foreign56 words, compounds, and `verb+suffix` (-ly, -ify, -ish). Short single words are almost always57 taken on `.com`; **compounds and coined words** are where `.com` wins are found.583. **Batch-check** with the script across the TLDs the user cares about (default `.com,.ai`).594. **Present results grouped by availability**, leading with names available on the user's60 preferred TLD. For each, give a one-line rationale (what it evokes) so the choice is informed.615. **Remind** that RDAP-available ≠ final price; premium names cost more — verify at a registrar62 (Cloudflare Registrar is at-cost and a good default if the user already uses Cloudflare).6364## Tips65- Default to checking `.com` and `.ai`; add `.app`/`.io`/`.dev` for developer-facing tools.66- If the user already owns domains (e.g. registered at Cloudflare), check whether one fits67 before suggesting new purchases — reusing an owned domain is free.68- Avoid names colliding with direct competitors or trademarks; flag near-misses you notice.
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