Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token. It is a reasoning model that is incredibly s…
Model details →StepFun: Step 3.5 Flash vs xAI: Grok Code Fast 1
StepFun: Step 3.5 Flash wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
Grok Code Fast 1 is a speedy and economical reasoning model that excels at agentic coding. With reasoning traces visible in the response, developers can steer Grok Code for high-quality work flows.
Model details →Side-by-side comparison
| Capability | StepFun: Step 3.5 Flash | xAI: Grok Code Fast 1 | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 262K | 256K | 🏆 StepFun: Step 3.5 Flash |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $0.10 | $0.20 | 🏆 StepFun: Step 3.5 Flash |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $0.30 | $1.50 | 🏆 StepFun: Step 3.5 Flash |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | — | — | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is StepFun: Step 3.5 Flash better than xAI: Grok Code Fast 1?
StepFun: Step 3.5 Flash wins on 3 of 6 axes — pricing and capability skew in its favour for most workloads.
What's the price difference between StepFun: Step 3.5 Flash and xAI: Grok Code Fast 1?
Input: $0.10 vs $0.20 per 1M tokens. Output: $0.30 vs $1.50 per 1M tokens.
What context windows do StepFun: Step 3.5 Flash and xAI: Grok Code Fast 1 support?
StepFun: Step 3.5 Flash supports up to 262K tokens. xAI: Grok Code Fast 1 supports up to 256K tokens.
Do both StepFun: Step 3.5 Flash and xAI: Grok Code Fast 1 support tool calling?
StepFun: Step 3.5 Flash: yes. xAI: Grok Code Fast 1: yes.