Best LLM for Coding 2026 | AI Coding Model Rankings & Benchmarks | Onyx AI

Coding LLM Leaderboard

Which AI model writes the best code? We rank every major LLM — open and closed source — across software engineering, code generation, competitive programming, and agentic coding benchmarks.

Roshan Desai · Last updated: 2026-07-20

CodingReasoning

Model Rank Params Cost per 1M Performance % Best Use Case
Claude Fable 5 S - $10.00 100% Software Engineering
GPT-5.6 Sol S - $5.00 95% Software Engineering
Claude Opus 4.8 A - $5.00 88.6% Software Engineering
GPT-5.5 A - $5.00 88.7% Software Engineering
Claude Sonnet 5 A - $2.00 85.2% Software Engineering
Kimi K3 S 2.8T $3.00 80% Code Generation
MiniMax M3 S 428B $0.30 80.5% Code Generation
DeepSeek-V4-Pro A 1.6T $0.43 80.6% Code Generation

Cost vs. Coding Performance

Which models give you the best coding performance for the price? Top-left is the sweet spot — high performance, low cost.

Best Coding LLMs by Benchmark

Best at Software Engineering

How does each model perform on real-world software engineering tasks? Hover any bar for details.

Model Performance %
Claude Fable 5 100%
GPT-5.5 88.7%
Claude Opus 4.8 88.6%
Claude Sonnet 5 85.2%
MiniMax M3 80.5%

Best for Code Generation

Model Performance %
Grok 3 100%
GPT-5.5 85%
Gemini 3.1 Pro 93%

Best in Competitive Coding

Model Performance %
DeepSeek-V4-Pro 100%
GPT-5.5 85%
DeepSeek R1 49%

Best at Terminal Coding

Model Performance %
GPT-5.6 Sol 89%
Claude Fable 5 85%
Kimi K3 81%

Hardest Software Engineering Tasks

Model Performance %
Claude Fable 5 50%
GPT-5.6 Sol 68%
Claude Opus 4.8 59%

Coding Benchmark Scores & Pricing

Complete coding benchmark results and pricing for every model. Click any column header to sort.

Model Params Input $/1M Output $/1M SWE-bench Verified LiveCodeBench Terminal-Bench 2.0
Claude Fable 5 - $10.00 $50.00 95.0 N/A 84.3
Claude Opus 4.8 - $5.00 $25.00 88.6 N/A 74.6
Claude Sonnet 5 - $2.00 $10.00 85.2 N/A 80.4
DeepSeek R1 671B $0.28 $0.42 49.2 90.2 N/A
DeepSeek V3.2 685B $0.28 $0.42 67.8 N/A N/A
DeepSeek-V4-Flash 284B $0.14 $0.28 79.0 N/A N/A
DeepSeek-V4-Pro 1.6T $0.43 $0.87 80.6 N/A N/A

Compare Coding LLMs Head-to-Head

Select two models to see how they compare across all coding and reasoning benchmarks.

Comparison: Claude Opus 4.8 vs GPT-5.5

Benchmark Claude Opus 4.8 GPT-5.5
GPQA Diamond 93.6 93.6
SWE-bench Verified 88.6 88.7
SWE-bench Pro 69.2 59.4
Terminal-Bench 2.1 74.6 85.6
Benchmarks won 1 2