StepFun: Step 5 Preview vs SpaceXAI: Grok 4.20 Multi-Agent
A side-by-side comparison of StepFun: Step 5 Preview ($3.50 / 1M tokens) and SpaceXAI: Grok 4.20 Multi-Agent ($4.38 / 1M tokens) using current USD prices and capabilities from the api14 catalog. Both run through the same OpenAI-compatible API.
Specifications
| StepFun: Step 5 Preview | SpaceXAI: Grok 4.20 Multi-Agent | |
|---|---|---|
| Provider | StepFun | xAI |
| Input | $3.50 / 1M tokens | $4.38 / 1M tokens |
| Output | $9.45 / 1M tokens | $8.75 / 1M tokens |
| Cache read | $0.35 / 1M tokens | $0.70 / 1M tokens |
| Web search | - | $17.50 / 1K searches |
| Context window | 1,048,576 | 2,000,000 |
| Max output | 64,000 | 1,800,000 |
| Input | text, image, video | text, image, file |
| Output | text | text |
| Tool calling | ||
| Structured output | ||
| Reasoning control | ||
| Added | Oct 8, 2026 | Mar 31, 2026 |
Key differences
- StepFun: Step 5 Preview is 20% cheaper on input tokens.
- SpaceXAI: Grok 4.20 Multi-Agent is 7% cheaper on output tokens.
- SpaceXAI: Grok 4.20 Multi-Agent reads 1.9× more context (2,000,000 tokens).
- Only StepFun: Step 5 Preview supports tool calling.
- A request with 1,000 input and 500 output tokens costs $0.00823 with StepFun: Step 5 Preview and $0.00875 with SpaceXAI: Grok 4.20 Multi-Agent.
In depth
StepFun: Step 5 Preview is made by StepFun, and SpaceXAI: Grok 4.20 Multi-Agent is made by xAI. Both are text output models in the text category, so neither one returns images or audio; whatever you send in, you get written text back. The naming tells you something about emphasis: Step 5 Preview is a preview release from StepFun, while Grok 4.20 Multi-Agent signals a multi-agent design from xAI. Both are reachable through api14 alongside each other, which makes them easy to compare on the same workload.
The clearest split is context and input handling. Grok 4.20 Multi-Agent has the bigger context window, so it can hold substantially more material in a single call, and it accepts text, image and file inputs. Step 5 Preview accepts text, image and video inputs, which makes it the one to reach for when your input is video rather than a document. On parameters, Step 5 Preview exposes a wider set, including tools and tool_choice, along with frequency_penalty, presence_penalty, repetition_penalty, min_p, top_k and seed. Grok 4.20 Multi-Agent supports a narrower set: reasoning and reasoning_effort, logprobs and top_logprobs, response_format, structured_outputs, temperature, top_p, max_tokens and seed. Structured outputs and reasoning controls are available on both, so those are not deciding factors. Tool calling is the notable asymmetry, since only Step 5 Preview lists tools and tool_choice.
For task selection, start with the input type. If you are feeding video, Step 5 Preview is the natural choice because it is the only one of the two that lists video as an input modality. If you are feeding long documents, large codebases or files, Grok 4.20 Multi-Agent fits better: it takes file input and has the larger context window, so you can avoid chunking. If your workflow depends on function calling or tool use, Step 5 Preview is the safer pick because tools and tool_choice are in its supported parameter list. If you need fine control over sampling, Step 5 Preview also gives you more knobs, such as top_k, min_p and the penalty parameters. On cost, Step 5 Preview is the cheaper option for input, while Grok 4.20 Multi-Agent is cheaper for output, so the better value depends on whether your workload is input heavy or output heavy. Check the live price table for the actual numbers.
Calling either model through api14 works the same way, because the gateway is OpenAI compatible. You point your client at the api14 base URL, send your request to the chat completions endpoint, and set the model field to the id you want. To use StepFun's model, set the model id to stepfun/step-5-preview. To use xAI's model, set it to x-ai/grok-4.20-multi-agent. Everything else in the request body stays the same shape: messages, temperature, max_tokens and the rest. Switching between the two is a one line change to the model id, so you can route different requests to different models without rewriting your integration. Just remember that parameters are not perfectly interchangeable, so if you rely on tools or tool_choice, keep those calls on Step 5 Preview, and if you rely on file input or the larger context, keep those on Grok 4.20 Multi-Agent.
Switch with one string
Both models use the same endpoint and request shape. Change the model value from "stepfun/step-5-preview" to "x-ai/grok-4.20-multi-agent" and prompts, streaming and tools keep working.
import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api14.com/api/v1",
apiKey: process.env.API14_API_KEY,
});
const result = await client.chat.completions.create({
"model": "x-ai/grok-4.20-multi-agent",
"messages": [
{
"role": "user",
"content": "Explain vector databases in two sentences."
}
]
});
console.log(result.choices[0].message.content);
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