Model Comparison

GPT-5.3 CodexDeepSeek V3.1 Reasoner
Let's see who can write code better - GPT-5.3 Codex or DeepSeek V3.1 Reasoner

Model Information

GPT-5.3 Codex

OpenAI

Description

Next-generation coding-optimized model from OpenAI with enhanced autonomous development capabilities

Specifications

Context Window272K
Max Output33K
ReleasedFeb 2026
API

Pricing (per 1M)

In / Out
$1.5/ $12

Key Features

Advanced autonomous codingEnhanced code reviewMulti-step reasoningFull-stack development

Strengths

  • State-of-the-art coding benchmarks
  • Superior autonomous task completion
  • Excellent code review capabilities
  • Large context window

Weaknesses

  • Premium pricing
  • Optimized for coding over general tasks

Agent Support

No known agents

DeepSeek V3.1 Reasoner

DeepSeek

Description

DeepSeek V3.1 Thinking mode

Specifications

Context Window128K
Max Output33K
ReleasedDec 2024
API

Pricing (per 1M)

In / Out
$0.07/ $1.68

Key Features

Performance improvementsBug fixesBetter stability

Strengths

  • More reliable than V3
  • Better performance
  • Improved efficiency

Weaknesses

  • Incremental improvements only
  • Still limited API access

Agent Support

No known agents