Comparisons / GPT-5.4 vs GPT-5.3 Codex
AI models for coding · HN opinions Nov 2025 – Nov 2026
GPT-5.4 vs GPT-5.3 Codex: what developers actually say
Based on 168 opinions on Hacker News from developers who discussed these two, most of them first-hand users.
GPT-5.4 comes out ahead on the volume of evidence and on code quality. It has 114 opinions from 105 authors, and its code quality mentions run 37 positive to 14 negative. GPT-5.3 Codex has a slightly higher approval share, 74% against 72%, on 54 opinions. Three of the four explicit comparisons favor GPT-5.4. Choose GPT-5.3 Codex for speed, cost, and orchestration: its speed mentions are 3 positive and 0 negative, and one user rated its orchestration above GPT-5.4.
When developers explicitly said they prefer one or switched: 3 picked GPT-5.4, 1 picked GPT-5.3 Codex.
Choose GPT-5.4 if
- Want the model with the most evidence: 114 opinions from 105 authors
- Care most about code quality: 37 positive mentions against 14 negative
- Work in large codebases: 6 positive mentions and 0 negative
Choose GPT-5.3 Codex if
- Want speed: 3 positive mentions and 0 negative
- Are cost-sensitive: 9 positive cost mentions against 1 negative
- Need orchestration: one user rated it better than GPT-5.4 there
Where each one wins and loses
PraiseComplaintsA = GPT-5.4B = GPT-5.3 Codex
Code quality
Reliability
Cost & pricing
Autonomy
Large codebases
UX
Speed
Why developers switched
Picked GPT-5.4
Says 5.3 Codex needed 5.2 for design work, while GPT-5.4 handled both design and execution better.HN comment · Jun 20, 2026
Calls GPT-5.4 a significant jump over 5.3 Codex, getting tasks right first try with more refined, less spaghetti-like edits.HN comment · Mar 6, 2026
Ran a zero-shot RTS game test and found GPT-5.4 output better than 5.3 Codex and Opus 4.6.HN comment · Mar 5, 2026
Picked GPT-5.3 Codex
Says GPT-5.3 Codex is much better at orchestration and does what it claims, while GPT-5.4 suits exploration and brainstorming.HN comment · Apr 23, 2026
Summaries are paraphrased. Each links to the original comment.
Side by side
| GPT-5.4 | GPT-5.3 Codex | |
|---|---|---|
| Approval | 72% | 74% |
| Last 90 days | – | – |
| Opinions | 114 | 54 |
| First-hand users | 101 | 51 |