AI Coding Assistants
OpenAI’s software engineering agent with GPT-6 Astra, GPT-6.1 Sol workhorse integration, and terminal workflows.
Codex: OpenAI’s software engineering agent with GPT-6 Astra, GPT-6.1 Sol workhorse integration, and terminal workflows. Pricing: From $8/mo + usage. Best for Repository-scale implementation, refactoring, debugging, testing, and review with tool use and Developers moving between the ChatGPT desktop app, web, terminal, IDE, and mobile Remote.
Overview
Codex is OpenAI's specialized software engineering agent built to plan, execute, debug, and review complex programming workloads across repository-scale codebases. Operating within terminal environments, development editors, and desktop agent interfaces, Codex leverages advanced reasoning architectures including GPT-6 Astra alongside GPT-6.1 Sol ($2/$10 API workhorse with $0.10 cached input, rolling out from 2026-09-29), GPT-6 Sol and configurable legacy tiers to analyze directory structures, execute automated test suites, and implement multi-file refactors. It works best for software engineers, engineering managers, and technical leads seeking autonomous task execution, code generation, and pull request verification.
The core caveat is that interactive agent execution draws from assigned subscription quotas and rolling hourly rate windows, while programmatic automation requires metered API keys with separate token billing. Task completion speed and token consumption scale with repository size, test suite complexity, and multi-agent reasoning depth. Engineering teams should start with interactive development logins, define clear task boundaries for autonomous modifications, and isolate long-running background tasks from production API budgets.
Pricing
Access routes
Pricing may differ across app subscriptions, API usage, team workspaces, and enterprise contracts. See the pricing guide for current plan and meter details.
From $8/mo
Codex is included across ChatGPT Free, Go, Plus, and Pro. Free and Go provide limited trial access, while Plus and higher tiers get fuller access, with the available models set by each ChatGPT plan; eligible users can buy credits after included limits.
From $20/seat/mo
Standard Business seats include ChatGPT and Codex with baseline usage plus optional shared workspace credits. Standard seats require at least two users and use fixed per-user billing.
Team pricing
Usage-based Codex-only access for a Business workspace, with no fixed seat fee or minimum. It requires workspace credits and does not include ChatGPT access.
Custom
Organization access is contract-based, with workspace controls and shared credits governed by the applicable Enterprise or Edu agreement.
Usage-based API
API-key use is billed separately by model and token type. ChatGPT subscriptions and Codex credits do not include OpenAI API usage, and the Responses API multi-agent beta is a separate developer surface.
Input types
text, image, code, file, url
Output types
text, image, code, file
Supported platforms
Web, iOS, Android, Mac, Windows, Linux
Delivery modes
Web app, Mobile app, Desktop app, Chat app, CLI, IDE extension, SDK
Company
OpenAI
Founded
2015
Headquarters
San Francisco, California, USA
Category
AI Coding Assistants
Evidence boundary
Editorial guidance grounded in official product sources.
FAQ
Codex offers GPT-6.1 Sol, released 2026-09-29 and listed on Plus and Pro, as its workhorse model for repository-scale agentic coding, with GPT-6 Sol still available and GPT-6 Astra for high-complexity frontier tasks. GPT-6.1 Sol uses 2.5 credits per 1M cached input tokens against 5 for GPT-6 Sol. Usage draws on ChatGPT Work allowances or workspace credits, while direct API-key integration is billed under OpenAI API pricing.
No. Max gives the selected model more time to reason about one task. Ultra uses subagents to work on separate parts in parallel and is available in Codex on Plus and higher plans.
No. ChatGPT Work is a broader agent for research, apps, files, and finished business materials. It uses Codex technology and shares the agentic usage pool, while Codex remains the developer-focused coding experience.
Codex joined the ChatGPT desktop app on macOS and Windows. Existing users can update normally and keep their projects, settings, and workflows, with Codex remaining a dedicated view.
No. OpenAI describes an experimental Codex feature that carries notes across context windows and searches earlier windows. It is not an unlimited single context window and is not yet the default at launch; confirm support and settings before relying on it.
Codex starts with access and included usage through eligible ChatGPT plans. Extra usage may draw from credits where eligible, while API-key use is billed separately under OpenAI API pricing.
Recent updates
Event date
Version GPT-6.1 Sol
OpenAI released GPT-6.1 Sol in Codex, rolling out from Pro to Plus, Business, Enterprise and Edu, at 50 input, 2.5 cached and 250 output credits per million tokens. The refreshed Codex CLI added voice steering and an /agents view, and Codex Cloud added reusable environments for Plus and higher plans.
Official source OpenAI — DevDay 2026 Recap
Verified
Event date
Version 0.155.0
Codex added GPT-6 Sol as its primary software engineering workhorse alongside GPT-6 Astra, supporting 1.05M context and 128k output across terminal and repository workflows.
Official source ChatGPT & Codex changelog — GPT-6 Sol Workhorse
Verified
Event date
Version 0.153.4
Codex CLI 0.153.4 fixes Astra visibility in the bundled model picker and makes Astra the default when no model is configured. It also restricts asynchronous-question guidance to sessions where the required tool is available.
Official source ChatGPT & Codex changelog — Codex CLI 0.153.4
Verified
Event date
Version 0.153.1
Codex CLI 0.153.1 added support for configuring GPT-6 Astra through the API without changing the default model or displaying Astra in the model picker. Availability still depends on the API account.
Official source ChatGPT & Codex changelog — Codex CLI 0.153.1
Verified
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