GPT-5.3-Codex vs Laguna by Poolside: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of GPT-5.3-Codex and Laguna by Poolside — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
GPT-5.3-Codex
OpenAI
Agentic coding model combining Codex and GPT‑5 training for faster, reasoning-rich code generation and interactive developer collaboration.
Key features
- Agentic Workflow: Acts as a steerable coding agent that performs multi-step tasks, provides frequent progress updates, and accepts real-time guidance while executing long-horizon engineering workflows.
- Frontier Code & Reasoning: Combines Codex and GPT‑5 training stacks to deliver best-in-class code generation with stronger general reasoning and professional knowledge for complex problem solving.
- Faster Generation for Codex Users: Optimized runtime that is ~25% faster for users of Codex surfaces, reducing iteration time for code authoring and interactive sessions.
- Cross-Surface Availability: Available across Codex app, CLI, IDE extensions, and web (for paid ChatGPT subscribers) enabling consistent workflows in editors, terminals, and the browser.
- Collaboration & Steering: Improved collaboration behaviors that let users steer the agent while it works—supporting conversational correction, test-driven workflows, and iterative design.
- Enhanced Cybersecurity Capabilities: Demonstrates elevated cyber capabilities in internal evaluations (first model to meet multiple high-level thresholds), enabling advanced vulnerability discovery and red-team style assessments under controlled conditions.
- Transition/Access Support: Integrates with existing Codex tools and workflows; API access is planned to roll out after initial ChatGPT-integrated availability, with CLI and app updates to select the model.
- Agentic coding behavior with interactive steering and frequent progress updates
- Frontier code generation and stronger general reasoning (combines Codex + GPT-5 training stacks)
- ~25% faster inference for Codex users compared to GPT-5.2-Codex
- Available across Codex surfaces: Codex app, CLI, IDE extensions, and Codex Cloud/web
- Real-time variant (GPT-5.3-Codex-Spark) offering much faster generation (15x) and up to 128k context (research preview)
- Designed for long-horizon, multi-file development, large-scale code transformations, and collaborative workflows
- Higher assessed cybersecurity capabilities (documented in model/system card; marked as High under Preparedness Framework)
- API access rolling out separately; initial availability requires ChatGPT sign-in (OAuth) on Codex surfaces
Best for
- Long-Horizon Feature Development: Orchestrate multi-file feature builds, writing tests, implementing functionality, and iterating on fixes with the agent autonomously while a developer supervises and guides progress.
- Interactive Pair-Programming: Use the model in IDE extensions or the Codex app as a collaborative partner to draft code, refactor modules, and respond to inline developer feedback in real time.
- Large-Scale Code Transformations: Automate broad codebase changes—migration of APIs, bulk refactors, and modernization tasks—by instructing the agent to propose, test, and apply transformations.
- Test-Driven Development Assist: Drive red/green TDD workflows where the agent prefers creating failing tests first, then implementing and refining code until tests pass, accelerating reliable feature delivery.
- Automated Code Review & QA: Generate detailed code reviews, identify potential bugs, and suggest fixes or security hardenings across repositories to streamline review cycles.
- Security Assessment (Controlled): Run cyber-range style scenarios and vulnerability discovery assessments for defensive research and hardening within responsible use constraints and governance.
- End-to-end software development and multi-file code transforms
- Pair-programming and interactive coding assistants inside IDEs
- Automated code review and refactoring at scale
- Building and steering long-horizon engineering workflows and agents
- Security auditing, vulnerability discovery assistance, and cybersecurity exercises
- CI/tooling automation where an agent maintains and updates codebases
Laguna by Poolside
Poolside
Poolside's family of open Mixture-of-Experts foundation models for agentic coding — XS.2 runs locally, M.1 reaches 72.5% on SWE-bench Verified.
Key features
- Two Model Sizes: Laguna XS.2 (33B total / 3B active) and Laguna M.1 (225B total / 23B active) target different latency and capability needs.
- Mixture-of-Experts Architecture: Routes each token through a subset of experts for efficiency at large scale.
- Local Deployment: XS.2 is small enough to run on a Mac with 36 GB of RAM via Ollama under an Apache 2.0 license.
- Strong SWE-bench Results: XS.2 hits 68.2% and M.1 reaches 72.5% on SWE-bench Verified.
- Bundled Coding Agent: Ships 'pool,' a lightweight terminal-based coding agent.
- Agent Client Protocol: Includes a dual ACP client-server used internally for agent RL training and evaluation.
Best for
- Local Agentic Coding: Running XS.2 on a laptop for private, offline code generation and editing.
- High-Capability Code Tasks: Using M.1 for harder, long-horizon software engineering work.
- Self-Hosted Deployments: Building on open weights to avoid third-party API dependencies.
- Research & Fine-Tuning: Adapting permissively licensed weights for custom coding workflows.
- Benchmarking: Evaluating agentic coding performance against SWE-bench Verified and Pro.