> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # ResponsesRequestServiceTier The service tier to use for processing this request. `fast` is accepted as an alias for `priority`. ## Example Usage ```go theme={null} import ( "github.com/OpenRouterTeam/go-sdk/models/components" ) value := components.ResponsesRequestServiceTierAuto // Open enum: custom values can be created with a direct type cast custom := components.ResponsesRequestServiceTier("custom_value") ``` ## Values | Name | Value | | ------------------------------------- | -------- | | `ResponsesRequestServiceTierAuto` | auto | | `ResponsesRequestServiceTierDefault` | default | | `ResponsesRequestServiceTierFast` | fast | | `ResponsesRequestServiceTierFlex` | flex | | `ResponsesRequestServiceTierPriority` | priority | | `ResponsesRequestServiceTierScale` | scale |