Grok 4 Fast Reasoning vs Together AI Qwen2-72B-Instruct
Grok 4 Fast Reasoning (2025) and Together AI Qwen2-72B-Instruct (2024) are frontier reasoning models from xAI and Alibaba. Grok 4 Fast Reasoning ships a 2M-token context window, while Together AI Qwen2-72B-Instruct ships a 33K-token context window. On pricing, Together AI Qwen2-72B-Instruct costs $0.7/1M input tokens versus $1.25/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Together AI Qwen2-72B-Instruct is ~79% cheaper at $0.7/1M; pay for Grok 4 Fast Reasoning only for reasoning depth.
Decision scorecard
Local evidence first| Signal | Grok 4 Fast Reasoning | Together AI Qwen2-72B-Instruct |
|---|---|---|
| Decision fit | Long context and Vision | Classification and JSON / Tool use |
| Context window | 2M | 33K |
| Cheapest output | $2.5/1M tokens | $0.7/1M tokens |
| Provider routes | 2 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4 Fast Reasoning has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 Fast Reasoning has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4 Fast Reasoning uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Grok 4 Fast Reasoning for Long context and Vision.
- Together AI Qwen2-72B-Instruct has the lower cheapest tracked output price at $0.7/1M tokens.
- Together AI Qwen2-72B-Instruct uniquely exposes Structured outputs in local model data.
- Local decision data tags Together AI Qwen2-72B-Instruct for Classification and JSON / Tool use.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Grok 4 Fast Reasoning
$1,625
Cheapest tracked route: xAI Console
Together AI Qwen2-72B-Instruct
$735
Cheapest tracked route: Together AI
Estimated monthly gap: $890. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Grok 4 Fast Reasoning and Together AI Qwen2-72B-Instruct; plan for SDK, billing, or endpoint changes.
- Together AI Qwen2-72B-Instruct is $1.8/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Together AI Qwen2-72B-Instruct adds Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for Together AI Qwen2-72B-Instruct and Grok 4 Fast Reasoning; plan for SDK, billing, or endpoint changes.
- Grok 4 Fast Reasoning is $1.8/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Structured outputs before moving production traffic.
- Grok 4 Fast Reasoning adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2024-06-07 |
| Context window | 2M | 33K |
| Parameters | — | 72B |
| Architecture | decoder only | decoder only |
| License | Proprietary | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4 Fast Reasoning | Together AI Qwen2-72B-Instruct |
|---|---|---|
| Input price | $1.25/1M tokens | $0.7/1M tokens |
| Output price | $2.5/1M tokens | $0.7/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 Fast Reasoning | Together AI Qwen2-72B-Instruct |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | Yes |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Grok 4 Fast Reasoning, multimodal input: Grok 4 Fast Reasoning, reasoning mode: Grok 4 Fast Reasoning, and structured outputs: Together AI Qwen2-72B-Instruct. 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.
For cost, Grok 4 Fast Reasoning lists $1.25/1M input and $2.5/1M output tokens, while Together AI Qwen2-72B-Instruct lists $0.7/1M input and $0.7/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Together AI Qwen2-72B-Instruct lower by about $0.93 per million blended tokens. Availability is 2 providers versus 1, so concentration risk also matters.
Choose Grok 4 Fast Reasoning when reasoning depth, larger context windows, and broader provider choice are central to the workload. Choose Together AI Qwen2-72B-Instruct 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. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which has a larger context window, Grok 4 Fast Reasoning or Together AI Qwen2-72B-Instruct?
Grok 4 Fast Reasoning supports 2M tokens, while Together AI Qwen2-72B-Instruct supports 33K 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 Fast Reasoning or Together AI Qwen2-72B-Instruct?
Together AI Qwen2-72B-Instruct is cheaper on tracked token pricing. Grok 4 Fast Reasoning costs $1.25/1M input and $2.5/1M output tokens. Together AI Qwen2-72B-Instruct costs $0.7/1M input and $0.7/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 Fast Reasoning or Together AI Qwen2-72B-Instruct open source?
Grok 4 Fast Reasoning is listed under Proprietary. Together AI Qwen2-72B-Instruct is listed under Open Source. 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 Fast Reasoning or Together AI Qwen2-72B-Instruct?
Grok 4 Fast Reasoning 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 Fast Reasoning or Together AI Qwen2-72B-Instruct?
Grok 4 Fast Reasoning 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 Fast Reasoning and Together AI Qwen2-72B-Instruct?
Grok 4 Fast Reasoning is available on Microsoft Foundry and xAI Console. Together AI Qwen2-72B-Instruct is available on Together AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-20. Data sourced from public model cards and provider documentation.