MoonshotAI: Kimi K3 vs StepFun: Step 3.7 Flash
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-12.
| MoonshotAI: Kimi K3 | StepFun: Step 3.7 Flash | |
|---|---|---|
| Vendor | moonshotai | stepfun |
| Quality Score | 100 | 100 |
| Input Price | $0.19/M | $0.20/M |
| Output Price | $16.00/M | $1.15/M |
| Context Window | 1,048,576 | 262,144 |
| Max Output | 943,718 | 230,400 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Step 3.7 Flash costs $0.49 and Kimi K3 costs $4.19, so Step 3.7 Flash is about 8.6 times cheaper for the same work.
Kimi K3 reads up to 1,048,576 tokens at once, roughly 1,573 pages of text, against about 393 pages for Step 3.7 Flash.
Across the 18 tasks where they differ, Kimi K3 scores higher on 13 (SQL Generation, Code Review, Code Refactoring and others), Step 3.7 Flash on 5 (Code Completion, Regex Writing, JSON Extraction and others).
Kimi K3 was released in July 2026 and Step 3.7 Flash in May 2026.
Pick Kimi K3 if you need long documents or the stronger all-round task scores; pick Step 3.7 Flash if you need lower cost.
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 | MoonshotAI: Kimi K3 | StepFun: Step 3.7 Flash |
|---|---|---|
| SQL Generation | 132 | 131 |
| Code Review | 132 | 126 |
| Code Completion | 128 | 129 |
| Code Refactoring | 136 | 127 |
| Bug Fixing | 136 | 130 |
| Unit Test Generation | 124 | 121 |
| Code Documentation | 128 | 126 |
| Regex Writing | 116 | 119 |
| CI/CD Pipelines | 120 | 117 |
| CSV / Spreadsheet Cleanup | 132 | 128 |
| ETL Scripting | 128 | 122 |
| JSON Extraction | 128 | 131 |
| Bulk Data Labeling | 125 | 129 |
| OCR / Document Parsing | 131 | 128 |
| Table Extraction from PDFs | 131 | 128 |
| Long-Document Summarization | 136 | 129 |
| Short-Form Summarization | 120 | 123 |
| Blog Post Writing | 120 | 119 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →