Alright, let’s talk tokens! 🪙 You know how it goes in AI land: you’re feeding your model the same darn input tokens over and over again. 🔁 System prompts, big chunks of context… and ching, ching, ching goes your API bill! 💸 Annoying, right?!
Well, Google’s Gemini API is trying to ease that pain, and they’ve got a couple of ways to cache that repetitive stuff. The NEW hotness is…
✨ Implicit Caching (The “It Just Works” Magic!) ✨ This bad boy is ON BY DEFAULT for Gemini 2.5 models! 🔥 If parts of your request look familiar (think: same system prompt at the start), Gemini tries to be smart and AUTOMATICALLY passes back cost savings if it scores a cache hit! Less work for you, potential savings for your wallet! 😉
Google Thinking Fondly of Your Wallet (BIG NEWS!) 🤑
On May 8th, 2025, Google announced they’re officially rolling out the “highly requested feature” (aka, what devs were actually yelling for!) in the Gemini API: That awesome IMPLICIT CACHING for Gemini 2.5 models!
So, automatic cost savings passed directly to YOU, the developer, without needing to set up some clunky “explicit cache”! Less hassle, more cha-ching! 💰
How This Implicit Magic Works 🪄
- When you send a request to a Gemini 2.5 model, if the beginning of your prompt (the “prefix”) matches one you’ve sent before… BAM! 🎯 CACHE HIT!
- Google says they’ll “dynamically pass cost savings back to you” – we’re talking that same awesome 75% token discount on the cached part! 🥳
PRO TIP (Google Recommended! 💡)
- Put all your repetitive stuff (system prompts, instructions, big chunks of context that stay the same) at the VERY BEGINNING.
- Tack on the new stuff (like the user’s unique question or changing details) at the END. (More nitty-gritty details are in the Gemini API docs if you wanna get super nerdy.)
“Show Me The Discount!”
Wanna see the savings in action? If you’re using Gemini 2.5 models, keep an eye out for cached_content_token_count in your usage metadata. That little number tells you how many tokens got the discount. Sweet! ✅
So, What’s the Deal? 🤔
This implicit caching is a big win! Easier savings, less faffing about with manual cache setups for most common use cases. If you still like full control or are using older Gemini 2.0 models, explicit caching ain’t dead, it’s still there for ya! 💪
Wanna master this and make your prompts cache-friendly? BEST PRACTICES? 👉 Read here!
