Connecting Evermail to ChatGPT and OpenAI
Evermail runs a remote MCP server that any MCP-capable tool can call. How you connect depends on which OpenAI product you're using — and one of them can't connect yet. Here's the honest breakdown.
What works today
Evermail's MCP server accepts two ways in: an API key sent as an X-API-Key request header, or OAuth sign-in with an Evermail account. What a tool can do decides which of them applies.
| Where you want to use it | Status |
|---|---|
| OpenAI API (Responses API, your own code) | Works today — jump to setup |
| ChatGPT web app (chatgpt.com, developer mode) | Not verified yet — where it stands |
| Claude (web, desktop, and Code) | Works today — see Connecting Claude |
You'll need an Evermail account on a Starter, Pro, Team, or Enterprise plan; see Billing & Plans. The API-key methods below also need a key from app.evermail.ai/settings/integrations — click Create API key, name it something like "ChatGPT", and copy the value starting with em_live_ immediately. It's only shown once.
OpenAI API — Responses API
If you're building something with OpenAI's API, you can hand it the Evermail MCP server directly. The Responses API accepts custom headers, so our API key works without any extra plumbing.
Add Evermail as an MCP tool
Pass an mcp tool in your request, with your Evermail key in the headers map:
{
"model": "gpt-5.6",
"input": "Find the Henderson contract from 2019 in my archive",
"tools": [
{
"type": "mcp",
"server_label": "evermail",
"server_url": "https://mcp.evermail.ai/mcp",
"headers": { "X-API-Key": "em_live_your_key_here" },
"require_approval": "never"
}
]
}Optionally narrow the tools
Evermail exposes eight tools. If you only want the model to search and read — never export — restrict it with allowed_tools:
"allowed_tools": ["search_emails", "get_email", "list_mailboxes"]Keep the key server-side
The request above contains a credential that grants full read access to your entire archive. Send it from your backend — never from browser or mobile client code.
Model names and API shapes change. Check OpenAI's current MCP and connectors guide before you build — the field we rely on here is headers on the MCP tool object.
ChatGPT web app
The missing piece on our side is gone: Evermail now supports OAuth sign-in, which is the scheme ChatGPT's custom connectors use. We haven't finished verifying the ChatGPT path against a real account, so we're not publishing steps we haven't walked through ourselves.
Where this stands: ChatGPT's custom connectors support no authentication and OAuth — there is no field for a custom request header, so the API-key route below never applied to it. Evermail's side of the OAuth handshake (sign-in, consent screen, and token issuance — the same flow Claude uses) is live and verified. What remains is confirming ChatGPT's connector UI against it end to end. We'd rather ship verified steps late than broken steps twice.
If you want to be told the moment it's confirmed, email support@evermail.ai and we'll add you to the list.
In the meantime, if your goal is to ask questions about your archive in a chat interface, Claude works today and takes about two minutes to set up.
Any other MCP client
The test is simple: can the tool send a custom HTTP header with its MCP requests? If yes, it can connect to Evermail today.
Evermail's server speaks the Streamable HTTP transport. The legacy HTTP+SSE transport is not enabled, so don't point a client at /sse. If your tool accepts a raw mcpServers configuration block, use this:
{
"mcpServers": {
"evermail": {
"type": "http",
"url": "https://mcp.evermail.ai/mcp",
"headers": { "X-API-Key": "em_live_your_key_here" }
}
}
}Our server is reached from the AI provider's cloud, not from your computer — so it has to be publicly reachable, which mcp.evermail.ai is. Nothing needs opening on your network.
Common errors
| Error | What it means |
|---|---|
401 Unauthorized | The API key is missing, wrong, or revoked — or the account is on the Free plan, which can't create API keys. Create a fresh key at Settings → Integrations. |
403 Forbidden | The key is valid but the plan no longer includes MCP access. Check Settings → Billing. |
404 Not Found | The URL is wrong. It must be exactly https://mcp.evermail.ai/mcp — no trailing slash, and not /sse. |
429 Too Many Requests | Rate limit of 20 requests per minute per IP address. Wait a minute and retry. |
What the API key can do
An Evermail API key grants full read access to your workspace's entire archive — anything you or a teammate could search or open in the Evermail app, a connected AI tool can too. Treat it like a password: don't share it, don't commit it to a repository, and don't put it in client-side code. Revoke a key at any time from Settings → Integrations; that immediately cuts off anything using it.
Evermail only sends the specific emails a tool call asks for. What the AI provider does with data you send it is governed by their privacy policy, not ours.
Ready to connect?
Wire up the Responses API today — or connect Claude in about two minutes.
Create an API key →