Gemini 3.5 Flash vs Grok 4
Gemini 3.5 Flash (2026) and Grok 4 (2025) are frontier-tier reasoning models from Google DeepMind and xAI. Gemini 3.5 Flash ships a 1.05m-token context window, while Grok 4 ships a 256k-token context window. On SWE-bench Verified, Gemini 3.5 Flash leads by 1.3 pts. On pricing, Grok 4 costs $1.25/1M input tokens versus $1.50/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 3.5 Flash fits 4x more tokens; pick it for long-context work and Grok 4 for tighter calls.
Decision scorecard
Local evidence first| Signal | Gemini 3.5 Flash | Grok 4 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1.05m | 256k |
| Cheapest output | $9/1M tokens | $2.50/1M tokens |
| Provider routes | 4 tracked | 4 tracked |
| Shared benchmarks | SWE-bench Verified leader | 4 shared |
Decision tradeoffs
- Gemini 3.5 Flash holds a shared-benchmark lead on SWE-bench Verified, ahead by 1.3 points.
- Gemini 3.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Local decision data tags Gemini 3.5 Flash for Coding, RAG, and Agents.
- Grok 4 has the lower cheapest tracked output price at $2.50/1M tokens.
- Local decision data tags Grok 4 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Gemini 3.5 Flash
$3,450
Cheapest tracked route/tier: Google AI Studio
Grok 4
$1,625
Cheapest tracked route/tier: xAI Console
Estimated monthly gap: $1,825. 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.
- Grok 4 is $6.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Gemini 3.5 Flash is $6.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-05-19 | 2025-07-09 |
| Context window | 1.05m | 256k |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-01 | - |
Pricing and availability
| Pricing attribute | Gemini 3.5 Flash | Grok 4 |
|---|---|---|
| Input price | $1.50/1M tokens | $1.25/1M tokens |
| Output price | $9/1M tokens | $2.50/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 3.5 Flash | Grok 4 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Gemini 3.5 Flash | Grok 4 |
|---|---|---|
| SWE-bench Verified | 78.0 | 76.7 |
| Google-Proof Q&A | 92.2 | 87.5 |
| Humanity's Last Exam | 40.2 | 25.4 |
| ARC-AGI-2 | 72.1 | 15.9 |
Continue comparing
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Last reviewed: 2026-07-10. Data sourced from public model cards and provider documentation.