OpenAI: GPT-5.6 Luna Pro (batch) vs SpaceXAI: Grok 4.3
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-07.
| OpenAI: GPT-5.6 Luna Pro (batch) | SpaceXAI: Grok 4.3 | |
|---|---|---|
| Vendor | openai | x-ai |
| Quality Score | 100 | 100 |
| Benchmark Score | - | 58.6 |
| Input Price | $0.10/M | $1.25/M |
| Output Price | $0.60/M | $2.50/M |
| Context Window | 1,050,000 | 1,000,000 |
| Max Output | 128,000 | 900,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | - | 62.0 |
| ai_index_agentic | - | 39.8 |
| ai_index_coding | - | 69.7 |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, GPT-5.6 Luna Pro (batch) costs $0.25 and Grok 4.3 costs $1.88, so GPT-5.6 Luna Pro (batch) is about 7.5 times cheaper for the same work.
Both take in a similar amount of text: 1,050,000 and 1,000,000 tokens, about 1,575 and 1,500 pages.
Across the 20 tasks where they differ, GPT-5.6 Luna Pro (batch) scores higher on 3 (Code Completion, Bulk Data Labeling, Short-Form Summarization), Grok 4.3 on 17 (SQL Generation, Code Review, Code Refactoring and others).
GPT-5.6 Luna Pro (batch) was released in July 2026 and Grok 4.3 in April 2026.
Pick GPT-5.6 Luna Pro (batch) if you need lower cost; pick Grok 4.3 if you need the stronger all-round task scores.
Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.
Who wins by task?
| Task | OpenAI: GPT-5.6 Luna Pro (batch) | SpaceXAI: Grok 4.3 |
|---|---|---|
| SQL Generation | 133 | 158 |
| Code Review | 132 | 155 |
| Code Completion | 131 | 120 |
| Code Refactoring | 136 | 155 |
| Bug Fixing | 136 | 164 |
| Unit Test Generation | 124 | 144 |
| Code Documentation | 131 | 139 |
| Regex Writing | 119 | 130 |
| CI/CD Pipelines | 120 | 136 |
| Frontend Component Design | 122 | 138 |
| Data Analysis | 124 | 153 |
| CSV / Spreadsheet Cleanup | 133 | 147 |
| ETL Scripting | 128 | 145 |
| JSON Extraction | 131 | 134 |
| Bulk Data Labeling | 129 | 124 |
| OCR / Document Parsing | 131 | 141 |
| Table Extraction from PDFs | 131 | 141 |
| Long-Document Summarization | 137 | 152 |
| Short-Form Summarization | 123 | 120 |
| Blog Post Writing | 121 | 134 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →