# Best LLM for Code Completion

> Updated Oct 21, 2026 · evidence through Oct 21, 2026. Synthesized from cited community evidence and open benchmarks, not vendor marketing. Canonical page: https://modelmatchbook.com/best/coding-completion

Claude Sonnet 5.5 ranks first for Code Completion as of October 21, 2026. It scores 91.37% on LiveBench Coding (#1 of 59), an objective evaluation of code generation and completion. Claude Opus 5.5 is the next-ranked alternative. It achieves #1 rank on LMArena WebDev coding with Elo 1807, the highest human preference score in the evaluation, though it trails Sonnet 5.5 on objective LiveBench Coding at 89.25% (#2 of 59). [1,2,3]

## 1. Claude Sonnet 5.5
https://modelmatchbook.com/models/anthropic/claude-sonnet-5.5-20260928

Claude Sonnet 5.5 scores 91.37% on LiveBench Coding (#1 of 59), an objective evaluation of code generation and completion.

**Best when:** Its strongest result for this task is on LiveBench Coding, which measures code generation and completion. [1]

## 2. Claude Opus 5.5
https://modelmatchbook.com/models/anthropic/claude-opus-5.5-20260921

Claude Opus 5.5 achieves #1 rank on LMArena WebDev coding with Elo 1807, the highest human preference score in the evaluation, though it trails Sonnet 5.5 on objective LiveBench Coding at 89.25% (#2 of 59).

**Best when:** Prioritize for autocomplete when human preference rankings drive your quality metric, as it tops the LMArena WebDev leaderboard. [2]

## 3. Claude Fable 5.1
https://modelmatchbook.com/models/anthropic/claude-fable-5.1-20260831

Claude Fable 5.1 scores 86.38% on LiveBench Coding (#3 of 59), an objective evaluation of code generation and completion.

**Best when:** Its strongest result for this task is on LiveBench Coding, which measures code generation and completion. [5]

## 4. Kimi K3
https://modelmatchbook.com/models/moonshotai/kimi-k3-20260715

Kimi K3 ranks #12 of 99 on LMArena's WebDev coding arena (Elo 1655), a leaderboard built from blind human preference votes on coding tasks.

**Best when:** Its strongest result for this task is on LMArena WebDev, which measures practical, real-world coding quality. [4]

## 5. DeepSeek V4.1 Flash
https://modelmatchbook.com/models/deepseek/deepseek-v4.1-flash-20260910

DeepSeek V4.1 Flash scores 80.04% on LiveBench Coding (#18 of 59), an objective evaluation of code generation and completion.

**Best when:** Its strongest result for this task is on LiveBench Coding, which measures code generation and completion. [6]

## 6. GLM 5.2
https://modelmatchbook.com/models/z-ai/glm-5.2-20260616

GLM 5.2 scores 79.65% on LiveBench Coding (#19 of 59), an objective evaluation of code generation and completion.

**Best when:** Its strongest result for this task is on LiveBench Coding, which measures code generation and completion. [7]

## 7. GLM 5.3 Flash
https://modelmatchbook.com/models/z-ai/glm-5.3-flash-20260826

GLM 5.3 Flash ranks #22 of 99 on LMArena's WebDev coding arena (Elo 1607), a leaderboard built from blind human preference votes on coding tasks.

**Best when:** Its strongest result for this task is on LMArena WebDev, which measures practical, real-world coding quality. [8]

## 8. GPT-6.1 Sol
https://modelmatchbook.com/models/openai/gpt-6.1-sol-20260929

GPT-6.1 Sol ranks #4 of 99 on LMArena's WebDev coding arena (Elo 1753), a leaderboard built from blind human preference votes on coding tasks.

**Best when:** Its strongest result for this task is on LMArena WebDev, which measures practical, real-world coding quality. [9]

## FAQ

**What is the best model for Code Completion?**

Claude Sonnet 5.5 ranks first as of October 21, 2026. Claude Sonnet 5.5 scores 91.37% on LiveBench Coding (#1 of 59), an objective evaluation of code generation and completion. [1]

**What is the best alternative to Claude Sonnet 5.5?**

Claude Opus 5.5 ranks second. Claude Opus 5.5 achieves #1 rank on LMArena WebDev coding with Elo 1807, the highest human preference score in the evaluation, though it trails Sonnet 5.5 on objective LiveBench Coding at 89.25% (#2 of 59). [2,3]

**Which open-weight model ranks highest for Code Completion?**

Kimi K3 is the highest-ranked open-weight model, at #4. Kimi K3 ranks #12 of 99 on LMArena's WebDev coding arena (Elo 1655), a leaderboard built from blind human preference votes on coding tasks. [4]

## Sources
1. "Within the 59 catalog models matched to this evaluation: Scores 91.37% on LiveBench Coding (#1 of 59), an objective evaluation of code generation and completion." (LiveBench Coding, https://livebench.ai/)
2. "Within the 99 catalog models matched to this evaluation: Ranks #1 of 99 on LMArena's WebDev coding arena (Elo 1807), a leaderboard built from blind human preference votes on coding tasks." (LMArena WebDev (coding) arena, https://lmarena.ai/leaderboard)
3. "Within the 59 catalog models matched to this evaluation: Scores 89.25% on LiveBench Coding (#2 of 59), an objective evaluation of code generation and completion." (LiveBench Coding, https://livebench.ai/)
4. "Within the 99 catalog models matched to this evaluation: Ranks #12 of 99 on LMArena's WebDev coding arena (Elo 1655), a leaderboard built from blind human preference votes on coding tasks." (LMArena WebDev (coding) arena, https://lmarena.ai/leaderboard)
5. "Within the 59 catalog models matched to this evaluation: Scores 86.38% on LiveBench Coding (#3 of 59), an objective evaluation of code generation and completion." (LiveBench Coding, https://livebench.ai/)
6. "Within the 59 catalog models matched to this evaluation: Scores 80.04% on LiveBench Coding (#18 of 59), an objective evaluation of code generation and completion." (LiveBench Coding, https://livebench.ai/)
7. "Within the 59 catalog models matched to this evaluation: Scores 79.65% on LiveBench Coding (#19 of 59), an objective evaluation of code generation and completion." (LiveBench Coding, https://livebench.ai/)
8. "Within the 99 catalog models matched to this evaluation: Ranks #22 of 99 on LMArena's WebDev coding arena (Elo 1607), a leaderboard built from blind human preference votes on coding tasks." (LMArena WebDev (coding) arena, https://lmarena.ai/leaderboard)
9. "Within the 99 catalog models matched to this evaluation: Ranks #4 of 99 on LMArena's WebDev coding arena (Elo 1753), a leaderboard built from blind human preference votes on coding tasks." (LMArena WebDev (coding) arena, https://lmarena.ai/leaderboard)