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GPT-5.3-Codex vs GPT-5.6 Sol

Detailed technical comparison between GPT-5.3-Codex (OpenAI) and GPT-5.6 Sol (OpenAI). Review live API token pricing, context window capabilities, time-to-first-token latency, and verified benchmark scores side-by-side.

⚡ Executive Summary & Verdict

Comparison Snapshot

GPT-5.3-Codex: 1 WinvsGPT-5.6 Sol: 5 Wins
Context Leader

GPT-5.6 Sol

1,050,000 tokens
Agentic Tool-Calling

Tie

Equal Capability
Lowest Latency (TTFT)

Tie

Equal Speed
Input Price Leader

GPT-5.3-Codex

$1.75 / MTok
OpenAIactive

GPT-5.3-Codex

GPT-5.3-Codex is an advanced artificial intelligence model engineered by OpenAI. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, GPT-5.3-Codex represents a key architectural iteration in the OpenAI model family. First released in 2026-02-24, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 400,000 tokens (approximately 533 words), GPT-5.3-Codex processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View GPT-5.3-Codex Full Specs →
OpenAIactive

GPT-5.6 Sol

GPT-5.6 Sol is an advanced artificial intelligence model engineered by OpenAI. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, GPT-5.6 Sol represents a key architectural iteration in the OpenAI model family. First released in 2026-07-09, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,050,000 tokens (approximately 1,400 words), GPT-5.6 Sol processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.

View GPT-5.6 Sol Full Specs →

Technical Specifications

🏆 = Superior Spec
SpecificationGPT-5.3-CodexGPT-5.6 Sol
ProviderOpenAIOpenAI
Context Window400,000 tokens1,050,000 tokens🏆
Agent SuitabilityNot yet benchmarkedNot yet benchmarked
Time to First Token (TTFT)No public TTFT dataNo public TTFT data
Deployment Modelmanaged apimanaged api
Production StabilityStable GA (est.)Beta Access (est.)
API AvailableYesYes
Released Date2026-02-242026-07-09

API Pricing Comparison

Input Price per Million Tokens

GPT-5.3-Codex

$1.75

GPT-5.6 Sol

$2.00

Output Price per Million Tokens

GPT-5.3-Codex

$14.00

GPT-5.6 Sol

$10.00

💡 Cost Ratio: GPT-5.3-Codex is 1.1x cheaper per input token than GPT-5.6 Sol.

Want to test both models live?

Run side-by-side prompt benchmarks in our dynamic multi-model Sandbox. Compare execution speeds, latency metrics, and compute actual costs in real-time.

Benchmark Performance Metrics

Standardized Scores (0–100%)

Scores show verified raw accuracy percentages across standardized AI evaluation suites. Higher bars indicate superior performance in that domain.

MMLUGeneral knowledge & multi-task understanding
93.4%vs96.8%+3.4% GPT-5.6 Sol
GPT-5.3-Codex
GPT-5.6 Sol 🏆
HumanEvalPython coding & logic synthesis
98.5%vs96.2%+2.3% GPT-5.3-Codex
GPT-5.3-Codex 🏆
GPT-5.6 Sol
MATHComplex mathematical problem solving
91.8%vs95.4%+3.6% GPT-5.6 Sol
GPT-5.3-Codex
GPT-5.6 Sol 🏆
GPQAGraduate-level expert reasoning
81.2%vs87.9%+6.7% GPT-5.6 Sol
GPT-5.3-Codex
GPT-5.6 Sol 🏆
HellaSwagCommonsense reasoning and inference
98.2%vs99.2%+1.0% GPT-5.6 Sol
GPT-5.3-Codex
GPT-5.6 Sol 🏆
MT-BenchMulti-turn conversation flow quality
9.5%vs9.8%+0.3% GPT-5.6 Sol
GPT-5.3-Codex
GPT-5.6 Sol 🏆

GPT-5.3-Codex Quirks & Gotchas

No developer gotchas reported.

GPT-5.6 Sol Quirks & Gotchas

No developer gotchas reported.

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