Grok 4.20 Multi-Agent vs Step 3.5 Flash
Grok 4.20 Multi-Agent (2026) and Step 3.5 Flash (2026) are frontier-tier reasoning models from xAI and StepFun. Grok 4.20 Multi-Agent ships a 2m-token context window, while Step 3.5 Flash ships a 256k-token context window. On pricing, Grok 4.20 Multi-Agent ranges from $1.25 to $2.50/1M input tokens by tier; Step 3.5 Flash costs $0.10/1M input tokens. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Grok 4.20 Multi-Agent fits 8x more tokens; pick it for long-context work and Step 3.5 Flash for tighter calls.
Decision scorecard
Local evidence first| Signal | Grok 4.20 Multi-Agent | Step 3.5 Flash |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps |
| Decision fit | RAG, Agents, and Long context | Coding, Agents, and Long context |
| Context window | 2m | 256k |
| Cheapest output | $2.50/1M tokens | $0.30/1M tokens |
| Provider routes | 3 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4.20 Multi-Agent has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.20 Multi-Agent has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4.20 Multi-Agent uniquely exposes Vision, Multimodal, and Function calling in local model data.
- Local decision data tags Grok 4.20 Multi-Agent for RAG, Agents, and Long context.
- Step 3.5 Flash has the lower cheapest tracked output price at $0.30/1M tokens.
- Local decision data tags Step 3.5 Flash for Coding, Agents, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4.20 Multi-Agent
$1,625
Cheapest tracked route/tier: xAI Console
Step 3.5 Flash
$155
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $1,470. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Step 3.5 Flash is $2.20/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Function calling before moving production traffic.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok 4.20 Multi-Agent is $2.20/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Grok 4.20 Multi-Agent adds Vision, Multimodal, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-10 | 2026-01-29 |
| Context window | 2m | 256k |
| Parameters | — | 196B (11B active) |
| Architecture | - | mixture of experts |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | 2024-11 | - |
Pricing and availability
| Pricing attribute | Grok 4.20 Multi-Agent | Step 3.5 Flash |
|---|---|---|
| Input price |
| $0.10/1M tokens |
| Output price |
| $0.30/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4.20 Multi-Agent | Step 3.5 Flash |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Grok 4.20 Multi-Agent, multimodal input: Grok 4.20 Multi-Agent, function calling: Grok 4.20 Multi-Agent, tool use: Grok 4.20 Multi-Agent, and structured outputs: Grok 4.20 Multi-Agent. Both models share reasoning mode, 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.
For cost, Grok 4.20 Multi-Agent lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output, while Step 3.5 Flash lists $0.10/1M input and $0.30/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Step 3.5 Flash lower by about $1.47 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 3 providers versus 1, so concentration risk also matters.
Choose Grok 4.20 Multi-Agent when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Step 3.5 Flash when provider fit and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Grok 4.20 Multi-Agent or Step 3.5 Flash?
Grok 4.20 Multi-Agent supports 2m tokens, while Step 3.5 Flash supports 256k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Grok 4.20 Multi-Agent or Step 3.5 Flash?
Grok 4.20 Multi-Agent lists tiered pricing: 0-200,001t is $1.25/1M input and $2.50/1M output; 200,001t+ is $2.50/1M input and $5/1M output. Step 3.5 Flash lists $0.10/1M input and $0.30/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Grok 4.20 Multi-Agent or Step 3.5 Flash open source?
Grok 4.20 Multi-Agent is listed under Proprietary. Step 3.5 Flash 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 vision, Grok 4.20 Multi-Agent or Step 3.5 Flash?
Grok 4.20 Multi-Agent has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Grok 4.20 Multi-Agent or Step 3.5 Flash?
Grok 4.20 Multi-Agent has the clearer documented multimodal input signal in this comparison. If multimodal input 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 Multi-Agent and Step 3.5 Flash?
Grok 4.20 Multi-Agent is available on OpenRouter, xAI Console, and Vercel AI Gateway. Step 3.5 Flash is available on OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-29. Data sourced from public model cards and provider documentation.