GPT-5.6 vs Grok 4.5

xAI released Grok 4.5 on July 8, 2026, positioning it for coding, agentic tasks, and knowledge work. GPT-5.6 Sol costs $5 input and $30 output per million tokens and is generally available via the OpenAI API and Codex. xAI has not published per-token pricing for Grok 4.5 as of this writing; its prior flagship, Grok 4.3, is priced at $1.25 input and $2.50 output per million tokens.

Both models are deployable today. Grok 4.5 leans into agentic task management and broad platform integrations, including Databricks and Amazon Bedrock. GPT-5.6 Sol adds max and ultra reasoning modes, where ultra uses subagents for complex, multi-step work.

This page compares access, price, agentic fit, and compliance so you can pick the right model for your workload.

GPT-5.6 (Sol) vs. Grok 4.5: Side-by-Side

Price: Grok 4.5's per-token cost isn't published yet

xAI has not published official per-token pricing for Grok 4.5 as of this writing. Its prior flagship, Grok 4.3, is priced at $1.25 per million input tokens and $2.50 per million output tokens, a fraction of GPT-5.6 Sol's $5 and $30.

If Grok 4.5 launches near Grok 4.3's pricing, it would undercut Sol substantially on cost. Confirm current Grok 4.5 pricing directly on xAI's pricing page before budgeting, since it has not been finalized publicly at the time of writing.

GPT-5.6 also ships lower-cost siblings — Terra at $2 input / $12 output and Luna at $0.20 / $1.20 — for teams that don't need Sol's full reasoning depth.

• GPT-5.6 Sol: $5 input / $30 output per million tokens.
• Grok 4.5: pricing not yet published.
• Grok 4.3 (prior flagship): $1.25 / $2.50 per million tokens.

→ Compare per-token pricing for every AI model

Agentic and coding fit

Grok 4.5 is built for coding, agentic tasks, and knowledge work, with broad platform integrations including Databricks and Amazon Bedrock. That makes it a candidate for teams already standardized on those enterprise data platforms.

GPT-5.6 Sol targets the hardest coding and security research, and adds max and ultra reasoning modes for deep, multi-step problems, with ultra using subagents.

Both are recent, capable releases. The practical difference is ecosystem: Sol keeps you inside the OpenAI API and Codex, while Grok 4.5 leans on broader third-party platform integrations.

• Grok 4.5: agentic tasks, coding, Databricks and Amazon Bedrock integrations.
• GPT-5.6 Sol: hardest coding and security work, max/ultra reasoning modes.

GPT-5.6 vs Grok 4.5 benchmarks: what's actually published

Neither GPT-5.6's nor Grok 4.5's maker has published a same-day, apples-to-apples benchmark suite pitting these two exact versions against each other, so treat any comparison here as directional rather than a verified head-to-head.

Vendors have not published a directly comparable, head-to-head SWE-bench Verified score for these exact current-generation versions as of this writing. The most recent published reference points are Claude Opus 4.8 at about 88.6%, GPT-5 at about 74%, Grok 4 at about 75%, and Gemini 2.5 Pro at about 71% (Google) — treat these as directional, not a same-generation apples-to-apples test.

xAI has not yet published a SWE-bench Verified score specifically for Grok 4.5; its predecessor Grok 4 scored about 75%.

Until both vendors publish a matched benchmark run, the more reliable signal is a short pilot on your own tasks — coding, drafting, or analysis representative of your real workload.

• Claude Opus 4.8: ~88.6% on SWE-bench Verified.
• GPT-5: ~74% on SWE-bench Verified.
• Grok 4: ~75% on SWE-bench Verified.
• Gemini 2.5 Pro: ~71% on SWE-bench Verified.

Compliance: confirm Grok 4.5's certifications directly

GPT-5.6 inherits OpenAI's documented compliance stack: SOC 2, ISO 27001, and a HIPAA BAA on the API and Enterprise plans.

Grok 4.5 is a new release, and xAI's current certification status for it specifically was not detailed in public materials reviewed for this comparison. Confirm SOC 2, HIPAA BAA availability, and data-retention terms directly with xAI before sending regulated data.

• GPT-5.6: OpenAI SOC 2, ISO 27001, HIPAA BAA on API/Enterprise.
• Grok 4.5: confirm current certifications directly with xAI.

How to choose for your business

Choose GPT-5.6 Sol if you need documented compliance coverage today and want max/ultra reasoning modes for the hardest work. Choose Grok 4.5 if your stack already runs on Databricks or Amazon Bedrock and you want to evaluate a newer, potentially lower-cost agentic model.

Because Grok 4.5's pricing and certifications were not fully published at the time of writing, run a short paid pilot before committing budget, and confirm the current terms directly with xAI.

• Documented compliance today, deep reasoning modes: GPT-5.6 Sol.
• Databricks/Bedrock-native stack, evaluating a newer model: Grok 4.5.

The Verdict

GPT-5.6 Sol is the safer default today: documented pricing, documented compliance coverage, and mature reasoning modes. Grok 4.5 is a genuinely capable, brand-new release with strong agentic and platform-integration claims, but its pricing and certifications were not fully public at the time of writing.

If your business already runs on Databricks or Amazon Bedrock, it's worth piloting Grok 4.5 directly. For most other buyers, GPT-5.6 Sol's clearer pricing and compliance documentation make it the lower-risk pick right now.