Claude Integration with Microsoft 365: What Works in 2025

Is there a native Claude integration for Microsoft 365?

No. Microsoft's AI layer inside Word, Excel, Outlook, Teams and SharePoint is Copilot, built on OpenAI models, and Microsoft has not shipped a first-party Claude connector for the M365 suite. If you're looking for a "Claude for Microsoft 365" toggle in admin settings, it doesn't exist and there's no public roadmap suggesting Microsoft plans to add one.

That doesn't mean Claude can't be part of your Microsoft 365 workflows — it just means you have to build the connection yourself, using the tools Microsoft already exposes: Power Automate, the Graph API, Office Add-ins, and custom Teams apps. All of these can call an external AI API, including Claude's, the same way they'd call any third-party service. The rest of this article walks through the realistic ways to do that, and what to weigh when you go from "one person testing this" to "the whole team depends on it."

Why Copilot and Claude aren't interchangeable here

Copilot is baked into the M365 UI: it reads the document you're in, respects your tenant's permissions, and renders inline. Claude, by contrast, is a model you access through an API. Getting it into Office apps means routing your document content, email body, or spreadsheet data to an HTTP endpoint and bringing the response back — there's no equivalent of clicking a ribbon icon out of the box.

That's a real trade-off. You lose the zero-setup convenience of Copilot, but you gain the ability to choose Claude specifically for tasks where its reasoning, summarization quality, or longer context window fits your use case better — contract review, technical documentation, long-form analysis, or structured data extraction from messy inputs.

Practical ways to connect Claude to Microsoft 365

Power Automate with an HTTP connector

This is the fastest path for most teams. Power Automate's HTTP action can call any REST API, so you can build a flow that:

1. Triggers on a new email, a SharePoint file upload, or a Teams message
2. Sends the relevant text to Claude via an HTTP POST
3. Writes the response back to a SharePoint list, a Teams channel, or a reply email

{
  "method": "POST",
  "uri": "https://api.subtoapi.app/v1/messages",
  "headers": {
    "Authorization": "Bearer @{variables('SUBTOAPI_KEY')}",
    "Content-Type": "application/json"
  },
  "body": {
    "model": "claude-3-5-sonnet",
    "max_tokens": 1024,
    "messages": [
      { "role": "user", "content": "Summarize this document: @{triggerBody()?['text']}" }
    ]
  }
}

No custom code, no server to maintain — just a flow definition and an API key stored as a secure variable.

Graph API + a small backend service

If Power Automate's low-code model is too limiting, a lightweight service using the Microsoft Graph API can read from Outlook, OneDrive, or Teams, pass content to Claude, and write results back. This is the right call when you need branching logic, retries, or to combine Claude's output with other business logic before it lands anywhere in M365.

Custom Teams bot

For interactive use — asking Claude questions from inside a Teams channel — you build a bot with the Bot Framework SDK, register it in Teams, and have its message handler call the Claude API on each user message. This is more setup than a Power Automate flow but gives you a conversational interface your team already lives in.

Office Scripts for Excel

Office Scripts (TypeScript, run from Excel on the web or via Power Automate) can call an external API. You can have a script pull a range of cells, send it to Claude for classification or extraction, and write structured output back into the sheet — useful for cleaning up messy data exports or tagging free-text survey responses.

The part that gets skipped: keys, usage, and access control

Once more than one person or one flow is calling Claude, you run into the same problem every team hits with any LLM API: where does the key live, who can see it, and how do you know which flow burned through your usage this month.

Hardcoding an API key into a Power Automate flow or an Office Script works for a prototype. It falls apart when you have five flows, three developers, and no visibility into which one is generating cost. This is the gap SubToAPI is built for: it turns your existing Claude access into application API keys (sub_live_...) with per-key usage tracking, so each Power Automate flow, Teams bot, or Office Script can have its own key instead of one shared secret passed around in plaintext. Team and Scale plans add seats so multiple builders can manage their own keys under one account instead of everyone sharing credentials in a Teams chat.

If you're piecing together your first M365-to-Claude flow, the quickstart covers getting a key and making your first request, and the messages docs match the request shape used above.

Streaming and tool use inside M365 flows

Most Power Automate and Office Script scenarios don't need streaming — you want a complete response to write into a cell or a document. But if you're building a Teams bot where users expect a live, typing-style response, SubToAPI's streaming endpoint works the same way over server-sent events. And if your integration needs Claude to call out to internal functions — looking up a record before answering — tool use lets you define that without switching providers or rebuilding your request logic.

Governance considerations before you roll this out

• Data residency: know what document content leaves your tenant when it's sent to any external API, Claude included, and check it against your company's data policies.
• Permission scoping: Graph API and Power Automate connections should use the narrowest possible permissions — read a specific library, not the whole tenant.
• Logging: keep a record of what was sent and what came back, especially for anything touching contracts, HR data, or financial documents.
• Key hygiene: rotate API keys per integration rather than reusing one key across every flow, so a compromised flow doesn't expose everything.

None of this is unique to Claude — it's the same checklist you'd run through connecting any external AI service to Microsoft 365 — but it's worth doing before the third team member starts building their own flow with their own copy of the key.

questions

Does Microsoft offer a built-in Claude option alongside Copilot? No. Microsoft's native AI integration across Word, Excel, Outlook and Teams is Copilot. Adding Claude requires connecting it yourself via Power Automate, the Graph API, or a custom app.

What's the easiest way to try Claude with Microsoft 365 without writing code? Power Automate's HTTP connector, calling a Claude API endpoint directly from a flow triggered by an email, file upload, or Teams message. No custom application code is required.

How do I manage Claude API keys across multiple Power Automate flows or Teams bots? Use separate keys per integration rather than one shared secret. A service like SubToAPI generates per-app keys with usage tracking so you can see which flow is making calls and revoke access individually if needed.