GPT-5.3 Codex vs Claude Opus 4.8
GPT-5.3 Codex vs Claude Opus 4.8: Side-by-side API pricing and specs — call both with one OpenAI-compatible key on GetModel.
GPT-5.3 Codex
OpenAI · Text
OpenAI GPT-5.3 Codex, specialised for programming and agentic coding. Served through getmodel's stable Codex Pro pool over an OpenAI-compatible endpoint.
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Claude Opus 4.8
Anthropic · Text
Claude Opus 4.8 is Anthropic's flagship model for complex reasoning, agentic workflows and coding. On getmodel it runs through a stable Claude Code Max pool or a low-cost Kiro pool, over both Anthropic-native and OpenAI-compatible endpoints.
View details →Pricing comparison
| GPT-5.3 Codex | Claude Opus 4.8 | |
|---|---|---|
| Input / 1M tokens | $0.108 Cheaper | $0.442 |
| Output / 1M tokens | $0.866 Cheaper | $2.21 |
Specifications
| Provider | OpenAI | Anthropic |
| Type | Text | Text |
| Endpoints | openai | anthropic / openai |
How to call
One API key calls both models — just change the "model" field.
from openai import OpenAI
client = OpenAI(base_url="https://getmodel.ai/v1", api_key="$GETMODEL_API_KEY")
# GPT-5.3 Codex
client.chat.completions.create(model="gpt-5.3-codex", messages=[{"role":"user","content":"Hi"}])
# Claude Opus 4.8 (same key, just change "model")
client.chat.completions.create(model="claude-opus-4-8", messages=[{"role":"user","content":"Hi"}])