Model Comparison

GPT-5 CodexDeepSeek V3.1 Reasoner
Let's see who can write code better - GPT-5 Codex or DeepSeek V3.1 Reasoner

Model Information

GPT-5 Codex

OpenAI

Description

Flagship model from OpenAI optimised for coding tasks

Specifications

Context Window272K
Max Output33K
ReleasedSep 2025
API✓

Pricing (per 1M)

In / Out
$1.25/ $10

Key Features

CodingAdvanced reasoningMulti-modal native

Strengths

  • ✓State-of-the-art performance
  • ✓Optimised for coding
  • ✓Large context window

Weaknesses

  • ✗Likely very expensive
  • ✗Unknown specifications

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