+
+
+
+
+
+
+
+
VS
VS
VS
VS
VS
VS
GPT-5.3 Codex vs Step-3.5-Flash
Comprehensive side-by-side LLM comparison
. Both models have their strengths depending on your specific coding needs.
+
+
+
+
OpenAI
GPT-5.3 Codex, released by OpenAI in February 2026, is a coding-specialized large language model from the GPT-5.3 family. It targets software engineering workflows including automated code generation, test writing, and agentic multi-file editing, built on the incremental improvements of the GPT-5.3 generation.
+
+
+
+
StepFun
Step-3.5-Flash, released by StepFun on February 2, 2026, is a Mixture-of-Experts large language model with 197 billion total parameters and approximately 11 billion active parameters per inference. It features a 256K token context window using a 3:1 sliding-window-to-full-attention ratio, processing 100–350 tokens per second. Step-3.5-Flash targets agentic tasks, coding workflows, and open-source deployments requiring frontier reasoning capabilities with efficient inference, under an Apache 2.0 license.
1 days newer
GPT-5.3 Codex
OpenAI
2026-02
Step-3.5-Flash
StepFun
2026-02-02
Provider Availability & Performance
Available providers and their performance metrics
+
+
+
+
GPT-5.3 Codex
0 providers
+
+
+
+
Step-3.5-Flash
0 providers
+
+
+
+
GPT-5.3 Codex
Avg Score:0.0%
Providers:0
+
+
+
+
Step-3.5-Flash
Avg Score:0.0%
Providers:0