LLM Prompt Cache Options Across Providers
LLM Prompt Cache Options Across Providers A reference covering cache TTL options and other cache-control dimensions across major LLM providers as of May 2026. TTL mechanics Fixed-duration TTLs Anthropic: 5-min (default) and 1-hour (extended). Cache writes cost 1.25× base input for 5-min TTL, 2× for 1-hour. Cache reads ≈ 10% of base input. TTL refreshes on each read (sliding window). AWS Bedrock: 5-min default, 1-hour added Jan 2026 for Claude Sonnet 4.5, Haiku 4.5, Opus 4.5. Also refresh-on-read. OpenRouter (Gemini path): 5-min TTL that does NOT update on read (fixed window) — gateway-specific behavior worth checking when going through proxies. Arbitrary / configurable TTL Google Gemini explicit caching: No minimum or maximum bounds on TTL. Default 60 min. You can update TTL on an existing cache and delete it early to stop billing. Billed as cached_tokens × storage_duration (per token-hour), not via a write-time premium. Opaque / provider-managed retention OpenAI: No exposed TTL. Baseline ~5–10 min of idle retention; off-peak can persist up to 1 hour. Extended prompt caching retains KV tensors 1–2h typical, up to 24h max. DeepSeek, Grok, Moonshot, Groq, Kimi K2: Automatic, provider-managed, no exposed TTL. Implicit vs explicit control Implicit (zero-config): OpenAI, DeepSeek, Grok, Moonshot, Groq, Gemini implicit tier. Server decides what to cache when it detects a recurring prefix. Explicit (marked / lifecycle-managed): Anthropic and Alibaba use inline cache_control: {"type": "ephemeral"} markers. Gemini explicit caching exposes full CRUD on cache objects via API (create, get, update, delete) — caches behave like first-class resources, similar to Valkey keys. Cache breakpoints / layering Anthropic supports up to 4 cache_control breakpoints in a single request. You can mix TTLs within one request, but longer TTL blocks must appear before shorter TTL blocks in the prompt structure (tools → system → messages order). Practical use: 1-hour cache for stable system prompt + tool defs, 5-min cache for mid-conversation context, paying the higher write premium only on the truly stable prefix. ...