---
header: AI Accelerator
last_updated: '2026-09-23'
url: https://docs.fastly.com/products/ai-accelerator
---

[AI Accelerator](https://www.fastly.com/documentation/guides/compute/ai-accelerator/about-the-ai-accelerator-page) is a semantic caching solution for large language model (LLM) APIs used in generative artificial intelligence (AI) applications.

AI accelerator caches LLM queries based on semantic similarity, allowing for flexible caching of query results and faster response times to end users. AI Accelerator is compatible with multiple LLM products performing pass-through caching. Your Fastly credentials allow you to call supported LLM APIs, caching queries automatically. AI Accelerator passes through any responses, errors, or rate limits associated with your LLM provider.

Fastly AI Accelerator can help:

- Reduce user wait times between query and response
- Reduce fees by making fewer direct queries to LLM services

## Limitations and considerations

AI Accelerator has been designed to be vendor neutral, so it works with many different LLM providers, but you must have valid credentials for at least one supported LLM service. [A list of supported LLM providers is available here.](https://www.fastly.com/documentation/guides/compute/ai-accelerator/about-the-ai-accelerator-page#supported-llms) LLM providers are third-party technologies subject to their own terms and conditions for which you are responsible.

## Billing

AI Accelerator is an add-on and is priced in addition to Fastly services. Billing for Fastly AI Accelerator is based on the total number of incoming monthly requests to AI Accelerator. Consider setting a \[spend alert]\(https://www.fastly.com/documentation/guides/account-info/billing/about-the-spend-alert-page/) for your account to automatically be notified when your month-to-date bill approaches or meets a specific dollar amount.

You are responsible for any fees associated with the LLMs you choose. These fees will not be a part of your Fastly bill.

> **NOTE:** Some Fastly products can be purchased directly in the web interface on the [Products page](https://www.fastly.com/documentation/guides/account-info/billing/managing-product-purchases-and-trials/) by an account Superuser or User Admin. Be sure to review all limitations, considerations, and [pricing information](https://www.fastly.com/pricing) before purchase. Alternatively, contact your customer success manager or email [sales@fastly.com](mailto:sales@fastly.com) for product purchase or pricing information.