4ai for AI agents & developers

Let AI assistants and apps find premium .ai domains for your users. 4ai offers an MCP server, open JSON data, an OpenAPI description and embeddable widgets. Free, read-only, no API key.

MCP server

Connect any MCP client (streamable HTTP) to:

https://4ai.ai/mcp

Tools: estimate_domain_value (free value estimate for any .ai name), search_domains (by word, category, type, length), get_domain (details, offer link and comparable sales), list_categories and ai_domain_sales (publicly reported .ai sales). Every domain result includes an offer link, so the assistant can send the user straight to buying.

In Claude, add it as a custom connector (Settings → Connectors → Add custom connector) with the URL above. Other MCP-capable assistants and agent frameworks accept the same URL.

Open data

/data/domains.json: all 254 domains for sale, with categories, type, what each is good for and offer links.
/data/ai-domain-sales.json and CSV: publicly reported .ai sales with sources.
Registrations and Anguilla .ai revenue (CSV).
/openapi.json: OpenAPI 3.1 description, usable for GPT actions and tool calling.
/llms.txt and /llms-full.txt: plain-text summaries for language models.

The data is free to reuse under CC BY 4.0 with a link to 4ai.ai.

Deep links

Name ideas for a keyword: /ai-domain-name-generator/?q=health
Comparable sales for a name: /ai-domain-value-estimator/?q=agent.ai
A domain page with offer form: /domains/<name>-ai/#make-offer

Widgets for your site

Biggest .ai sales:

<div data-4ai-sales="5"></div>
<script src="https://4ai.ai/widget/ai-sales.js" async></script>

.ai domains for sale on 4ai (optional category: short, numeric, quantum, crypto, tech, ai, code, space, health, gaming, commerce, places, brands):

<div data-4ai-domains="6" data-category="crypto"></div>
<script src="https://4ai.ai/widget/ai-sales.js" async></script>