LLM Reference

Claude 3.7 Sonnet vs GPT-5.3-Codex

Claude 3.7 Sonnet (2024) and GPT-5.3-Codex (2026) compare a standalone API model against a coding-specialized model. Claude 3.7 Sonnet ships a 200k-token context window, while GPT-5.3-Codex ships a 400k-token context window. On SWE-bench Verified, GPT-5.3-Codex leads by 14.7 pts. On pricing, GPT-5.3-Codex costs $1.75/1M input tokens versus $3/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.

Treat this as a product-type comparison: Claude 3.7 Sonnet is standalone API model, while GPT-5.3-Codex is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.

Decision scorecard

Local evidence first
SignalClaude 3.7 SonnetGPT-5.3-Codex
Product typeStandalone API modelCoding-specialized model
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentscustom coding agents, code generation, and tool loops
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k400k
Cheapest output$15/1M tokens$14/1M tokens
Provider routes6 tracked3 tracked
Shared benchmarks1 sharedSWE-bench Verified leader

Decision tradeoffs

Choose Claude 3.7 Sonnet when...
  • Claude 3.7 Sonnet has broader tracked provider coverage for fallback and route flexibility.
  • Claude 3.7 Sonnet uniquely exposes Multimodal in local model data.
  • Local decision data tags Claude 3.7 Sonnet for Coding, RAG, and Agents.
Choose GPT-5.3-Codex when...
  • GPT-5.3-Codex holds a shared-benchmark lead on SWE-bench Verified, ahead by 14.7 points.
  • GPT-5.3-Codex has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • GPT-5.3-Codex has the lower cheapest tracked output price at $14/1M tokens.
  • GPT-5.3-Codex uniquely exposes Computer use in local model data.
  • Local decision data tags GPT-5.3-Codex for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate GPT-5.3-Codex

Claude 3.7 Sonnet

$6,150

Cheapest tracked route/tier: GCP Vertex AI

GPT-5.3-Codex

$4,900

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $1,250. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude 3.7 Sonnet -> GPT-5.3-Codex
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • GPT-5.3-Codex is $1/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Multimodal before moving production traffic.
  • GPT-5.3-Codex adds Computer use in local capability data.
GPT-5.3-Codex -> Claude 3.7 Sonnet
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • Claude 3.7 Sonnet is $1/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Check replacement coverage for Computer use before moving production traffic.
  • Claude 3.7 Sonnet adds Multimodal in local capability data.

Specs

Specification
Released2024-03-042026-02-05
Context window200k400k
Parameters
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2024-112025-08

Pricing and availability

Pricing attributeClaude 3.7 SonnetGPT-5.3-Codex
Input price$3/1M tokens$1.75/1M tokens
Output price$15/1M tokens$14/1M tokens
Providers

Capabilities

CapabilityClaude 3.7 SonnetGPT-5.3-Codex
VisionYesYes
MultimodalYesNo
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useNoYes
Parallel agentsNoNo

Benchmarks

BenchmarkClaude 3.7 SonnetGPT-5.3-Codex
SWE-bench Verified70.385.0

Continue comparing

Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.