domain-pre-flight

⚠️ Status: experimental / under active validation. Heuristics, score weights, and thresholds are still being calibrated against real-world domain decisions. Use it as one input — not the only one — when deciding whether to register a domain.

Pre-flight checks before registering a domain for a new site or app.

domain-pre-flight answers a single question: "Is this domain safe to register for a new project, or should I keep looking?"

It is not a domain investing / drop-catching tool. It is the last-mile checklist for engineers and founders who already have a domain in mind and want a quick read on whether it is clean, memorable, and free of obvious legacy abuse.

What v0.1 does

Check	What it tells you	Source
Basic structural check	length, hyphens, digits, IDN/punycode, syntactic validity (RFC 1035)	offline, no API
TLD risk score	per-TLD default risk based on Spamhaus / SURBL abuse statistics (.tk/.cf/.ml etc. heavily penalised)	static table
Past content history	Wayback Machine snapshot count, first/last archived date, archive span	archive.org (free, no auth)
Same-name handle check	GitHub / npm / PyPI / X / Instagram availability for the SLD	public APIs / HEAD requests
Typosquat / brand similarity	Levenshtein distance + homoglyph/bigram heuristics against ~120 widely-recognised brand stems	bundled list, offline
Trademark conflict (opt-in)	Pre-filled USPTO + EUIPO + J-PlatPat deeplinks for manual verification (deeplink-only — see ADR 0009)	offline, no API queries
Multi-language semantics	Negative-meaning scan across EN / ES / PT / JA / KO / ZH (curated bundled lists)	bundled lists, offline
LLMO fitness (experimental)	Pronunciation / memorability heuristic (cluster, vowel ratio, length, repeats) — 0–20 score	offline heuristics
Aggregate verdict	0–100 score, 4 bands (GREEN / YELLOW / ORANGE / RED), itemised deductions	derived

The CLI exits with 0 on GREEN/YELLOW, 1 on ORANGE, 2 on RED — convenient for CI gating in domain-procurement scripts.

Install

pip install domain-pre-flight        # not yet on PyPI — install from source while v0.1 is in flight
# or, from a clone:
pip install -e ".[dev]"

Usage

# Full check (basic + history + aggregate verdict)
domain-pre-flight check example.com

# Skip the network call to Wayback (offline only)
domain-pre-flight check example.com --no-history

# Include same-name handle availability across GitHub / npm / PyPI / X / Instagram
domain-pre-flight check example.com --check-handles

# JSON output for piping
domain-pre-flight check example.com --json

# History only
domain-pre-flight history example.com

# Handle availability only (subset selectable via --platforms)
domain-pre-flight handles example.com --platforms github,npm,pypi

# Typosquat / brand-similarity check only
domain-pre-flight typosquat goolge.com

# Trademark conflict (opt-in; queries USPTO + EUIPO, surfaces J-PlatPat deeplink)
domain-pre-flight check example.com --check-trademark
domain-pre-flight trademark example.com --jurisdictions us,eu

# Multi-language negative-meaning scan
domain-pre-flight semantics shineyo.com --languages ja

# LLMO fitness — pronunciation / memorability heuristic (experimental)
domain-pre-flight llmo apple.com

# Basic structural checks only
domain-pre-flight basic example.com

# Short alias
dpf check example.com

Example output

example.com  →  GREEN  score=100/100  — Looks clean. Proceed.

Basic checks
┃ Field              ┃ Value
┃ SLD                ┃ example
┃ TLD                ┃ com
┃ length / SLD label ┃ 11 / 7
┃ hyphens / digits   ┃ 0 / 0
┃ IDN / punycode     ┃ no
┃ syntax valid       ┃ yes
┃ TLD risk score     ┃ 0

Roadmap

The features below are planned but not yet implemented. Order is rough; PRs welcome.

Near-term — eliminate the most common "should not have registered this" failure modes

1. Same-name social / package availability — check whether the matching handle is free on GitHub, npm, PyPI, and major social networks. Shipped in v0.2 — dpf handles and --check-handles.
2. Typosquat / brand-similarity flag — Levenshtein distance and bigram similarity against a curated brand list. Shipped in v0.3 — dpf typosquat (default ON in dpf check, disable with --no-typosquat).
3. Trademark conflict check — query USPTO, EUIPO, and J-PlatPat for identical and confusingly similar marks. Shipped in v0.4, revised in v0.7.1 — dpf trademark and --check-trademark (opt-in). All three jurisdictions surface a pre-filled deeplink for manual verification; the live-query path was removed (ADR 0009) because none of the registries publishes a stable, documented, no-auth search API. This tool flags candidates, not legal opinions — consult counsel before acting on a flag.

Medium-term — quality-of-life and global readiness

4. Multi-language negative-meaning check — scan the SLD against major languages (EN / ZH / ES / PT / KO / JA) for slurs, vulgarities, or unfortunate readings. Shipped in v0.5 — dpf semantics (default ON in dpf check, disable with --no-semantics). Word lists live at data/negative_meanings/<lang>.txt and accept community PRs with citations.
5. Per-TLD default risk score (deeper) — extend the TLD table to use live Spamhaus / SURBL feed data instead of the static table. Refactored in v0.6 — TLD-risk table now lives at data/tld_risk.json and is loaded at runtime, with the embedded dict as a graceful fallback. scripts/refresh_tld_risk.py is the entry point; a monthly GitHub Actions workflow opens an auto-PR. Live feed integration (Interisle / DAAR) is currently a no-op stub — the script writes the curated baseline if no live source is available, so the bundle is always valid.
6. Pronunciation / memorability heuristics (LLMO fitness) — score how easily the domain can be dictated, spelled-back over voice, and recognised by AI search assistants. Shipped in v0.7 — dpf llmo (default ON in dpf check, disable with --no-llmo). 0–20 fitness score across four axes (cluster / vowel / length / repeats); marked experimental in output because the heuristics are subjective and English-leaning.

Opt-in — paid-API features (default OFF, not yet implemented)

7. Detailed backlink evaluation — referring-domain quality, anchor-text spam ratio, and historical link velocity from a paid provider (Ahrefs / Majestic / Moz). Will be exposed as an opt-in flag (planned name: --enable-backlinks) once the integration lands; provider and credentials will be configured via environment variables. Designed as a strict superset, not a replacement, for the free signals.

Out of scope (for now)

• Domain valuation / sale-price history (drifts into domain-investing territory)
• WHOIS scraping for marketing intelligence
• Bulk domain monitoring (this is a per-decision pre-flight, not an asset-management tool)

Design notes

• Free signals first. The default code path uses only public, no-auth APIs (Wayback Machine) and offline heuristics. Anything paid is opt-in.
• Deterministic where possible. The basic check and the score formula are pure functions; only the history check makes a network call.
• Not a replacement for human judgement. A green verdict is a "no obvious red flags," not a sign-off. Always inspect older Wayback snapshots manually before adopting a domain that has prior content.

Development

python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"

# Unit tests
pytest -q

# CLI smoke tests (offline mode skips the Wayback network call)
bash scripts/smoke.sh --offline
bash scripts/smoke.sh             # full run, hits Wayback Machine

CI runs pytest against Python 3.10 / 3.11 / 3.12 plus the offline smoke suite on every push and PR.

License

MIT — see LICENSE.

Documentation

This repo is structured for both human readers and AI coding agents (Claude Code, Cursor, etc.). Pick the doc that matches your task:

If you want to…	Read
Use the CLI	docs/guide/usage.md
Understand the codebase as a whole	CLAUDE.md, then docs/architecture.md
Add a new check / extend an existing one	docs/agents/extending-checks.md
Edit only data (brand list, word lists, TLDs)	docs/agents/data-updates.md
Tune scoring weights	docs/agents/tuning-scores.md
Understand why a design choice was made	docs/decisions/
Get the smallest possible context for one module	docs/context-cards/

The docs/agents/ and docs/context-cards/ directories are written for tasks that span exactly one module — load only the relevant card to keep context cost predictable.

Background

This project is a tools-side companion to the (Japanese-language) book 「2人ではじめる中古ドメイン・ビジネス: 目利き×運用の協業設計」 by Ken Imoto, which covers expired-domain-abuse policy boundaries, LLMO-era authority evaluation, revenue-share contracts, and exit-route economics for domain-and-content businesses. domain-pre-flight distils the "will I regret registering this name?" pre-flight subset of that material into a runnable check.