GPT-5.4 nano is the most lightweight and cost-efficient variant of the GPT-5.4 family, optimized for speed-critical and high-volume tasks. It supports text and image inputs and is designed for low-latency use cases such as classification, d…
Model details →OpenAI: GPT-5.4 Nano vs StepFun: Step 3.5 Flash (free)
OpenAI: GPT-5.4 Nano and StepFun: Step 3.5 Flash (free) are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
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 →Side-by-side comparison
| Capability | OpenAI: GPT-5.4 Nano | StepFun: Step 3.5 Flash (free) | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 400K | 256K | 🏆 OpenAI: GPT-5.4 Nano |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $0.20 | $0.00 | 🏆 StepFun: Step 3.5 Flash (free) |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $1.25 | $0.00 | 🏆 StepFun: Step 3.5 Flash (free) |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | — | 🏆 OpenAI: GPT-5.4 Nano |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | Yes | Tie |
Frequently asked questions
Is OpenAI: GPT-5.4 Nano better than StepFun: Step 3.5 Flash (free)?
OpenAI: GPT-5.4 Nano and StepFun: Step 3.5 Flash (free) are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between OpenAI: GPT-5.4 Nano and StepFun: Step 3.5 Flash (free)?
Input: $0.20 vs $0.00 per 1M tokens. Output: $1.25 vs $0.00 per 1M tokens.
What context windows do OpenAI: GPT-5.4 Nano and StepFun: Step 3.5 Flash (free) support?
OpenAI: GPT-5.4 Nano supports up to 400K tokens. StepFun: Step 3.5 Flash (free) supports up to 256K tokens.
Do both OpenAI: GPT-5.4 Nano and StepFun: Step 3.5 Flash (free) support tool calling?
OpenAI: GPT-5.4 Nano: yes. StepFun: Step 3.5 Flash (free): yes.