How to cut your LLM bill 40-70% with semantic caching

If your product uses language models, a good chunk of your bill goes to answering, over and over, questions that are essentially the same. “How do I cancel my subscription?” and “I want to unsubscribe, what do I do?” ask for the same thing, but to a model they’re two separate calls you pay for twice. That’s where semantic caching comes in.

What semantic caching is. Unlike a traditional cache —which only recognizes identical text— semantic caching compares the meaning of each query. It turns every question into a vector (an embedding) and checks, in a vector database, whether an answer already exists for a sufficiently similar question. If it does, it returns it instantly; if not, it calls the model and stores the result for next time.

How much it saves. In real workloads, 30-40% of queries are semantically similar. Since an answer served from cache costs practically nothing, that typically means 40-70% lower spend on that slice of queries. The more repetitive your case (support, FAQs, assistants), the bigger the savings.

Don’t OpenAI and Anthropic already cache? They do, but differently. Providers cache identical prefixes: the exact same text at the start of the prompt. That helps, but it doesn’t capture “same intent, different wording.” Semantic caching does — and the best part is it stacks on top of the provider’s: you first try to serve by meaning, and when you do call the model, you still benefit from the provider’s prefix discount. Two layers of savings, not one.

The role of BYOK. Reusing answers only truly saves money if there’s no middleman charging you a markup on every token. That’s why Semantara is BYOK: you use your own keys, keep your billing relationship with the providers, and the platform only charges the subscription. The cache savings are yours, in full.

How to start. Semantara exposes an OpenAI-compatible endpoint, so integrating it is just changing the base URL. From there, semantic caching and complexity-based routing work on their own, and you see the result in one simple metric: dollars saved per month. Want an estimate for your case? Try the savings calculator or start free.