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LLM ComparisonGPT-5 CodexGPT Image 1.5

GPT-5 Codex vs GPT Image 1.5

Compare GPT-5 Codex and GPT Image 1.5. Build AI products powered by either model on Appaca.

Model Comparison

FeatureGPT-5 CodexGPT Image 1.5
ProviderOpenAIOpenAI
Model Typetextimage
Context Window400,000 tokensN/A
Input Cost
$1.25/ 1M tokens
$5.00/ 1M tokens
Output Cost
$10.00/ 1M tokens
N/A

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Strengths & Best Use Cases

GPT-5 Codex

OpenAI

1. Purpose-Built for Agentic Coding

  • Optimized specifically for scenarios where the model must act as an autonomous or semi-autonomous coding agent.
  • Tailored for Codex workflows such as planning, editing, debugging, and multi-step tool-driven code tasks.

2. Advanced Coding Reasoning

  • Extends GPT-5's higher reasoning mode to better handle complex software logic and multi-file dependencies.
  • Produces more accurate, structured, and maintainable code across modern programming languages.

3. Strong Tool Use in Developer-Like Environments

  • Designed for Codex's agent environment, enabling the model to:
    • Read and modify files
    • Follow function signatures and API contracts
    • Navigate codebases with awareness of context and structure

4. Large Context Window for Full-Project Understanding

  • 400,000-token context allows ingestion of:
    • Entire repositories
    • Multiple files at once
    • Architectural descriptions
  • Enables long-range reasoning across codebases rather than isolated snippets.

5. Multimodal Capability for Development Tasks

  • Accepts text and image as input (great for screenshots of error logs, UI mocks, whiteboards).
  • Outputs text only, focusing its output precision on code, reasoning, and documentation.

6. Continuous Snapshot Updates

  • The underlying model version is regularly upgraded behind the scenes.
  • Ensures developers always use the best coding-enhanced GPT-5 variant without changing model names.

7. Reliable Instruction Following

  • Very strong adherence to constraints like:
    • File/folder structure requirements
    • Framework conventions
    • Naming patterns
    • Linting rules
  • Makes it suitable for production coding agents.

8. Broad API Integration

  • Available only in the Responses API, giving you:
    • Streaming
    • Structured outputs
    • Function calling
  • Allows creation of interactive coding tools and agent workflows with tight model control.

GPT Image 1.5

OpenAI

1. State-of-the-Art Image Generation

  • Produces high-quality, detailed images optimized for realism, style control and prompt fidelity.
  • Designed to handle complex visual scenes, compositions and lighting conditions.

2. Natively Multimodal Architecture

  • Understands and reasons over both text and images as inputs.
  • Ideal for workflows like editing based on reference images, expanding sketches or mockups and visual concept development.

3. Flexible Output Resolutions & Quality Levels

  • Supports multiple resolutions including 1024x1024, 1024x1536 and 1536x1024.
  • Offers three quality tiers (Low, Medium, High) to balance cost, speed and maximum detail.

4. Multiple Pricing Models

  • Pay-per-token for multimodal input: text tokens and image tokens.
  • Pay-per-image generation for final output: low, medium and high quality tiers.
  • Enables businesses to balance cost and output needs.

5. Broad Use Cases

  • Product photography and marketing assets.
  • Illustration, concept art and creative ideation.
  • UX/UI mockups.
  • Style-guided image creation.
  • Generating reference images for design or storytelling.

6. Supported Across Major API Endpoints

  • Available via Chat Completions, Responses, Realtime, Assistants and Images (generations/edits) endpoints.
  • Allows tight integration into automated creative pipelines or user-facing apps.

7. Simplified Model Behavior for Stability

  • No streaming, function calling, structured outputs or fine-tuning; focused solely on high-quality image generation.

8. Consistent Results via Snapshots

  • Supports snapshots for version locking to ensure long-term reproducibility.

9. Ideal For

  • Designers, marketers and creatives.
  • Product teams needing image assets.
  • App builders integrating image generation workflows.
  • Agencies producing visual content at scale.