Claude Opus 4.8 vs Grok 4 Heavy
Claude Opus 4.8 (2026) and Grok 4 Heavy (2025) are frontier reasoning models from Anthropic and xAI. Claude Opus 4.8 ships a 1m-token context window, while Grok 4 Heavy ships a 256k-token context window. On SWE-bench Pro, Claude Opus 4.8 leads by 29.4 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Claude Opus 4.8 is safer overall; choose Grok 4 Heavy when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.8 | Grok 4 Heavy |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps |
| Decision fit | Coding, RAG, and Agents | Coding, Long context, and Vision |
| Context window | 1m | 256k |
| Cheapest output | $25/1M tokens | - |
| Provider routes | 6 tracked | 0 tracked |
| Shared benchmarks | SWE-bench Pro leader | 1 shared |
Decision tradeoffs
- Claude Opus 4.8 holds a shared-benchmark lead on SWE-bench Pro, ahead by 29.4 points.
- Claude Opus 4.8 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Opus 4.8 has broader tracked provider coverage for fallback and route flexibility.
- Claude Opus 4.8 uniquely exposes Reasoning, JSON / Tool use, and Structured outputs in local model data.
- Local decision data tags Claude Opus 4.8 for Coding, RAG, and Agents.
- Local decision data tags Grok 4 Heavy for Coding, Long context, and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 4.8
$10,250
Cheapest tracked route/tier: Anthropic
Grok 4 Heavy
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Claude Opus 4.8 and Grok 4 Heavy; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning, JSON / JSON / Tool use, and Structured outputs before moving production traffic.
- No overlapping tracked provider route is sourced for Grok 4 Heavy and Claude Opus 4.8; plan for SDK, billing, or endpoint changes.
- Claude Opus 4.8 adds Reasoning, JSON / JSON / Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-05-28 | 2025-07-09 |
| Context window | 1m | 256k |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Not released | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2026-01 | 2024-11 |
Pricing and availability
| Pricing attribute | Claude Opus 4.8 | Grok 4 Heavy |
|---|---|---|
| Input price | $5/1M tokens | - |
| Output price | $25/1M tokens | - |
| Providers | - |
Capabilities
| Capability | Claude Opus 4.8 | Grok 4 Heavy |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | Yes | No |
| Parallel agents | Yes | No |
Benchmarks
| Benchmark | Claude Opus 4.8 | Grok 4 Heavy |
|---|---|---|
| SWE-bench Pro | 69.2 | 39.8 |
Continue comparing
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.