Grok 4.20 vs StepFun Step-2
Grok 4.20 (2026) and StepFun Step-2 (2025) are frontier reasoning models from xAI and StepFun. Grok 4.20 ships a 2M-token context window, while StepFun Step-2 ships a 128k-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Grok 4.20 fits 16x more tokens; pick it for long-context work and StepFun Step-2 for tighter calls.
Specs
| Released | 2026-01-01 | 2025-10-15 |
| Context window | 2M | 128k |
| Parameters | — | — |
| Architecture | - | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | - |
Pricing and availability
| Grok 4.20 | StepFun Step-2 | |
|---|---|---|
| Input price | $4.2/1M tokens | - |
| Output price | $12.60/1M tokens | - |
| Providers | - |
Capabilities
| Grok 4.20 | StepFun Step-2 | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Grok 4.20, function calling: Grok 4.20, tool use: Grok 4.20, and structured outputs: Grok 4.20. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Grok 4.20 has $4.2/1M input tokens and StepFun Step-2 has no token price sourced yet. Provider availability is 1 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Grok 4.20 when reasoning depth, larger context windows, and broader provider choice are central to the workload. Choose StepFun Step-2 when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, Grok 4.20 or StepFun Step-2?
Grok 4.20 supports 2M tokens, while StepFun Step-2 supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Grok 4.20 or StepFun Step-2 open source?
Grok 4.20 is listed under Proprietary. StepFun Step-2 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for reasoning mode, Grok 4.20 or StepFun Step-2?
Grok 4.20 has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for function calling, Grok 4.20 or StepFun Step-2?
Grok 4.20 has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for tool use, Grok 4.20 or StepFun Step-2?
Grok 4.20 has the clearer documented tool use signal in this comparison. If tool use is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4.20 and StepFun Step-2?
Grok 4.20 is available on xAI Console. StepFun Step-2 is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-04-19. Data sourced from public model cards and provider documentation.