Unlike Microsoft Copilot in Word, which relies on cloud-based AI services, our Word Add-in is local-first. All AI processing runs on your own machine using local LLMs, so your documents never leave your device. This local GPT in Word provides stronger data privacy, offline capability, and full control over models and updates—without requiring a Microsoft 365 Copilot subscription. Additionally, because it does not depend on Microsoft’s cloud services, it continues to work even if Copilot or Microsoft services experience outages or service disruptions.

No. Your document content stays on your computer at all times. All text processing is performed locally using on-device language models, and no content is sent to external servers or the cloud. You can run your local GPT in Word.

GPTLocalhost works with any LLM server that is compatible with the OpenAI Chat API. This means any LLM supported by those servers—including popular open-source models like LLaMA-family, Mistral, Falcon, and others—can be used with GPTLocalhost. You can also connect your own local or self-hosted models by simply pointing GPTLocalhost to your local inference endpoint.

Yes. The add-in is designed to work fully within Microsoft Word’s security model while keeping your data local.

Microsoft Word requires all add-ins to load over a secure HTTPS connection. Our add-in complies with this requirement by using a secure, encrypted local HTTPS connection. Because the AI model runs entirely on your own machine, we use a locally generated certificate to enable this secure communication.

Your documents are processed locally and are not sent to external cloud services by default. This approach aligns with Word’s security requirements while providing a local-first, privacy-focused alternative to cloud-based solutions like Microsoft Copilot.

Yes. The add-in is designed to run entirely on your local machine using local LLMs. After login, it works offline and can be deployed in fully air-gapped environments, with no internet connection or data leaving your device. Your local GPT in Word simply runs locally.

Our local Word Add-in is designed to function as a direct alternative to Microsoft Copilot in Word, offering a private, local GPT experience with your data never leaving your device.

However, it is developed to work alongside Copilot. You do not need to disable or uninstall Copilot to use our Add-in. You can choose to use our local tool for privacy-sensitive or cost-effective tasks, and still utilize Microsoft Copilot for its unique cloud-integrated features or organizational knowledge when needed.

Absolutely! While our primary focus is leveraging local LLMs for enhanced privacy and speed, our Word Add-in is fully capable of connecting to cloud-based LLMs as well.

We achieve this seamless integration by utilizing an LLM Proxy like LiteLLM, which acts as a unified gateway allowing our local application to communicate with various cloud providers (e.g., OpenAI, Anthropic). This hybrid approach provides a significant advantage over fixed, pricy subscription fees—like those charged by alternatives—because you benefit from a highly cost-effective, token-based usage model. You only pay for the specific resources you consume, giving you the power and flexibility of cloud LLMs with far greater control over your expenditure.

A local Word Add-in is a specific deployment option for Office Add-ins, according to Microsoft document. It is an Add-in that is designed to be sideloaded from a local file share (as opposed to being downloaded from a cloud store). This local deployment method is specifically intended for developer testing. It is used after development is complete to test the Add-in on a localhost environment before deploying it to the cloud for production.

Unlike most Word Add-ins, GPTLocalhost uses such local deployment to enable a local-only design. You can run your local GPT in Word privately in this way. By eliminating cloud deployment altogether, a local Add-in runs fully on the user’s machine and provides complete privacy.

Microsoft Word requires all Word Add-ins to communicate over a secure, encrypted HTTPS connection. This rule applies to both cloud-based Add-ins and local Add-ins. To use HTTPS, a security certificate is required. Because GPTLocalhost runs on the user’s local machine, it can simply use a local certificate to meet this requirement. It does not need a certificate issued by a public certificate authority.

When installing GPTLocalhost, the installer handles the creation of a self-signed local certificate automatically. But to successfully install and trust this local certificate for Microsoft Word to connect, it needs your explicit permission to modify your computer’s settings, ensuring a safe connection between Word and the Add-in.

For Mac users, please check here for details.
For Windows users, please check here for details.