Google Unveils Implicit Caching to Lower Costs of Accessing New AI Models

09.05.2025

Google has introduced a new feature in its Gemini API called “implicit caching,” designed to significantly reduce the cost of using its latest AI models. This feature aims to provide up to 75% savings on repetitive context passed to models through the Gemini API, benefiting third-party developers who are facing growing costs for accessing advanced AI capabilities. The feature supports the Gemini 2.5 Pro and 2.5 Flash models.

Implicit caching, which is automatic and enabled by default for Gemini 2.5 models, allows developers to access cost savings without any manual intervention. Unlike the previous explicit caching method, where developers had to manually define the most frequent prompts, implicit caching automatically detects common request patterns and reuses data from prior requests. This not only reduces the computational load but also cuts down on costs for developers.

The feature triggers cost savings when a new request shares a similar context or prefix with previous ones, making it more efficient for repetitive tasks. The minimum prompt token requirements for triggering implicit caching are 1,024 tokens for 2.5 Flash and 2,048 tokens for 2.5 Pro, which means developers don’t need to provide large amounts of data to benefit from savings.

While this new caching feature seems promising, Google advises developers to place repetitive context at the beginning of requests to maximize the chances of a cache hit. Context that may change frequently should be placed at the end of requests. However, Google has not provided third-party verification to guarantee that the automatic savings will meet expectations, so the effectiveness of the feature will be better understood through feedback from early users.

This rollout of implicit caching is expected to be a positive development for developers who have previously encountered high costs with Google’s Gemini models, particularly with the earlier explicit caching system, which faced criticism for its complexity and unexpected charges.