Part of Best LLM for Coding
Best LLM for Debugging & Code Review
Claude Sonnet 5.5 ranks first for Debugging & Code Review as of October 20, 2026.[1][2] It scores 91.37% on LiveBench Coding (#1 of 59), an objective evaluation of code generation and completion. Claude Opus 5.5 scores within two points, so read the top two as close rather than as a measured gap. Claude Opus 5.5 is the next-ranked alternative. It ranks #1 of 99 on LMArena's WebDev coding arena (Elo 1807), a leaderboard built from blind human preference votes on coding tasks.
- Best open-weight pick: Kimi K3 (#6)
- Compare Claude Sonnet 5.5 vs Claude Opus 5.5 →
About this recommendation
- Updated
- Evidence through
- Sources
- 8
- Revision
- v115
Decision audit
Why this result
Inspect the inputs and the computed order behind the recommendation.
Models screened
24
live candidates
Evaluation feeds
5
task-weighted
Winner coverage
33%
intended feed weight
Largest provider share
3 of 8
Anthropic
Anthropic: Claude Sonnet 5.5 leads the measured task comparison with 2 independent evaluation families. Community volume, release age and usage popularity add no ranking points. The leading scores are close under this policy.
Real-world track record is still developing. The recommendation can lead on independent measurements while practitioner reports accumulate.
Sources evaluated
These are the weights used in scoring. Missing measurements are omitted from each model’s average. A feed with no result for any model released in the last 60 days is stale and does not score until it catches up.
| Evaluation feed | Weight | Winner result | Field measured |
|---|---|---|---|
| SWE-rebenchstale | 0% | no current result | 0/24 |
| Aider Polyglotstale | 0% | no current result | 0/24 |
| LiveBench Coding (2026-06-25)Observed 2026-10-18 · evaluation date not supplied · claude-sonnet-5-5-max-effortfailing; last successful check 2026-10-18 | 50% | #1 | 24/24 |
| LMArena WebDevObserved 2026-10-19 · evaluation date not supplied · xhigh effort | 50% | #3 | 24/24 |
| SWE-bench Verifiedstale | 0% | no current result | 0/24 |
Provider concentration
Each exact model is scored separately; provider identity is not a ranking input.
- Anthropic3 models
- OpenAI2 models
- deepseek1 model
- Meta1 model
- Moonshot AI1 model
Decision table
Every published model is shown in computed order. Practitioner sources are distinct community threads, not the citations repeated in the prose below.
Anthropic · coverage 33%
#1 LiveBench Coding · #3 LMArena WebDev
Anthropic · coverage 33% · close score
#1 LMArena WebDev · #2 LiveBench Coding
Anthropic · coverage 33%
#3 LiveBench Coding · #5 LMArena WebDev
OpenAI · coverage 33%
#2 LMArena WebDev · #16 LiveBench Coding
OpenAI · coverage 33%
#4 LMArena WebDev · #16 LiveBench Coding
Moonshot AI · coverage 33%
#12 LiveBench Coding · #12 LMArena WebDev
Meta · coverage 33%
#11 LMArena WebDev · #14 LiveBench Coding
deepseek · coverage 33%
#18 LiveBench Coding · #20 LMArena WebDev
Task score averages the available, task-weighted measurements. Benchmark positions compare models matched to our catalog. Models measured by at least two independent evaluator families are considered first. Missing tests, practitioner report counts, popularity and release age add no points. Coverage describes evidence breadth, not a probability of correctness. Scores within two points are shown as close under this policy; this is not a statistical confidence interval. When the leading scores are that close, the model measured by more evaluator families ranks first.
- 01
Claude Sonnet 5.5Anthropic · $2 in / $10 out per M tokens · 1M context
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. - 02
Claude Opus 5.5Anthropic · $4 in / $20 out per M tokens · 1M context
Claude Opus 5.5 ranks #1 of 99 on LMArena's WebDev coding arena (Elo 1807), 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. - 03
Claude Fable 5.1Anthropic · $10 in / $50 out per M tokens · 1M context
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. - 04
GPT-6 AstraOpenAI · $10 in / $50 out per M tokens · 1.1M context
GPT-6 Astra ranks #2 of 99 on LMArena's WebDev coding arena (Elo 1774), 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. - 05
GPT-6.1 SolOpenAI · $2 in / $10 out per M tokens · 1.1M context
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. - 06
Kimi K3Moonshot AI · $0.24 in / $11.94 out per M tokens · 1.0M context · open-weight
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. - 07
Muse Spark 1.3Meta · $1.25 in / $4.25 out per M tokens · 1.0M context
Muse Spark 1.3 ranks #11 of 99 on LMArena's WebDev coding arena (Elo 1659), 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.No practitioner reports are linked yet, so no cautions are listed. Absence of reports is not evidence of reliability.
- 08
DeepSeek V4.1 Flashdeepseek · $0.056 in / $0.12 out per M tokens · 1.0M context · open-weight
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.
Frequently asked
- What is the best model for Debugging & Code Review?
- Claude Sonnet 5.5 ranks first as of October 20, 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 ranks #1 of 99 on LMArena's WebDev coding arena (Elo 1807), a leaderboard built from blind human preference votes on coding tasks.[2]
- Which open-weight model ranks highest for Debugging & Code Review?
- Kimi K3 is the highest-ranked open-weight model, at #6. 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.[3]
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 · Benchmark · Oct 18, 2026 - 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 · Benchmark · Oct 19, 2026 - 3
“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 · Benchmark · Oct 19, 2026 - 4
“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 · Benchmark · Oct 18, 2026 - 5
“Within the 99 catalog models matched to this evaluation: Ranks #2 of 99 on LMArena's WebDev coding arena (Elo 1774), a leaderboard built from blind human preference votes on coding tasks.”
LMArena WebDev (coding) arena · Benchmark · Oct 19, 2026 - 6
“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 · Benchmark · Oct 19, 2026 - 7
“Within the 99 catalog models matched to this evaluation: Ranks #11 of 99 on LMArena's WebDev coding arena (Elo 1659), a leaderboard built from blind human preference votes on coding tasks.”
LMArena WebDev (coding) arena · Benchmark · Oct 19, 2026 - 8
“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 · Benchmark · Oct 18, 2026
Rankings synthesized from community evidence and open benchmarks. See methodology. Not driven by vendor marketing.