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Claude Opus 4.6 vs GPT-5.3-Codex

Comprehensive comparison between Anthropic's Claude Opus 4.6 and OpenAI's GPT-5.3-Codex. Compare pricing, performance, features, and user reviews.

best ai for codingclaude vs codex

Claude Opus 4.6

Anthropic

Anthropic's flagship model with 1M token context (now default), adaptive thinking, and the highest agentic coding scores. Introduced Agent Teams for parallel autonomous coding. Nearly doubled ARC-AGI-2 score over Opus 4.5 (68.8% vs 37.6%).

$5/$25per M tokens
Details

GPT-5.3-Codex

OpenAI

OpenAI's coding-optimized model, surpassing Claude on SWE-bench. HN users praise its coding value and much more generous quotas than Claude. Ideal for intensive coding work.

$1.75/$14per M tokens
Details

Specs Comparison

SpecificationClaude Opus 4.6GPT-5.3-Codex
Context Window1000K256K
Max Output128K64K
Input (per 1M tokens)$5.00$1.75
Output (per 1M tokens)$25.00$14.00
Reasoning
Open Source

Scenario Score Comparison

Coding
96
vs
93
Writing
91
vs
—
Translation
—
vs
65
Data Analysis
—
vs
78
Conversation
—
vs
60
Image Gen
—
vs
50

Claude Opus 4.6

Pros

  • + Highest SWE-bench score (80.8%)
  • + 128K max output (doubled from 4.5)
  • + Adaptive thinking with effort levels
  • + Agent Teams for parallel coding
  • + Best instruction following in complex contexts

Cons

  • − 2x price of GPT-5.4
  • − Response prefilling removed (breaking change)
  • − Extended thinking deprecated
  • − Rate limits can be hit quickly on entry-level plans

GPT-5.3-Codex

Pros

  • + Coding-optimized
  • + Great value
  • + Generous quotas
  • + SWE-bench leader

Cons

  • − Text-only
  • − Weak at creative tasks
  • − Requires Codex-specific API

Recommendation

Choose Claude Opus 4.6 if you:

  • • Need highest swe-bench score (80.8%)
  • • Need 128k max output (doubled from 4.5)
  • • Need adaptive thinking with effort levels

Choose GPT-5.3-Codex if you:

  • • Need coding-optimized
  • • Need great value
  • • Need generous quotas

Based on scores across 6 scenarios, GPT-5.3-Codex performs better overall.

Claude Opus 4.6 Details GPT-5.3-Codex Details

Get Started with Claude Opus 4.6

1Sign up at claude.ai
2Choose Pro ($20/mo) for Opus access
3Start chatting or try Claude Code

💡 Free tier uses Sonnet. Upgrade to Pro for Opus.

Get Started with GPT-5.3-Codex

1Visit the provider's website
2Create an account
3Start using the model

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