Free · MCP server & REST API · no signup

Use DNSai in ChatGPT

Two paths: a Custom GPT "Action" built from the OpenAPI schema (works on Plus), or a full MCP connector via Developer mode (Business/Enterprise for read-write).

⚠ Custom GPT Action takes a key · the MCP connector is anonymous / OAuth

Works with: ChatGPT Plus and up (GPTs) · one domain per request

Each lookup = one domain or IP. Free: 10 lookups/day per IP (anonymous) or 100 lookups/day per key (free key).

↓ Download this guide (.md) drop it into your repo or paste it into your assistant

Running bulk / multi-domain or enterprise-scale lookups? → DNSai Pro & Enterprise

Set it up

Custom GPT Action (Plus and up) — key works here

Create or edit a GPT → Configure → Actions → Create new action → Import from URL and paste the schema. Set Authentication: None for the free anonymous tier, or API key → Bearer with a dk_free_… key for 100 lookups/day (shared across that GPT's users).

https://api.dnsai.com/openapi.json

MCP connector (Developer mode)

Settings → Connectors → Advanced → Developer mode ON, then Create and add the URL. Plus/Pro are read-only; full read-write needs Business/Enterprise (admin-enabled). Present-day Bearer support in this UI is unconfirmed — anonymous/OAuth is the documented path.

https://mcp.dnsai.com/mcp

OpenAI Codex CLI — key works here

Native remote MCP — no bridge. Add to ~/.codex/config.toml, then export DNSAI_TOKEN="dk_free_xxxxxxxx" and run codex.

[mcp_servers.dnsai]
url = "https://mcp.dnsai.com/mcp"
bearer_token_env_var = "DNSAI_TOKEN"

Your key. The Custom GPT Action accepts the key (API key → Bearer) and Codex reads it from an env var. The MCP connector runs anonymous/OAuth. Get a free key for 100 lookups/day.

Verify it works

In the GPT, ask:

Check the DMARC policy for nfl.com

Every result ends with a plain-English summary, a source link on dnsai.com, and your remaining quota.

Troubleshooting

Import-from-URL fails? Some setups block OpenAI's fetcher — download openapi.json and paste it inline instead. The schema is OpenAPI 3.1 with an absolute servers: https://api.dnsai.com/v1.
Free / Go plans can't create GPTs, and MCP read-write needs Business/Enterprise.

Sources: GPT Action authentication · ChatGPT Developer mode · Codex config reference

Need bulk, multi-domain, or the full API?

Pro unlocks bulk / multi-domain lookups; Enterprise adds large-scale scanning and the full programmatic API.

See plans & pricing →