BELLISTE / AI COMPARISON

Compare AI models

Choose two models from the same AI category to compare equivalent plans, capabilities and technical details.

First modelvsSecond model

GitHub Copilot

83%

OpenAI Codex

88%

Estimated Belliste score, based on the available capabilities, quality, features and pricing information. It is an indicative profile estimate, not an independent benchmark.

How this profile estimate is calculated

Capabilities contribute 35%, quality wording 30%, listed features 20%, and pricing 15% when available. When capability fields are absent, specialization breadth supplies a 25% fallback. Missing categories are omitted and the remaining weights are rescaled. The estimate uses each model’s own published profile; it does not measure answer accuracy or replace a hands-on test.

OverviewGitHub CopilotOpenAI Codex

PriceFree $0/month · Pro $10/user/month · Pro+ $39/user/month · Max $100/user/month. USD; additional usage charges apply.Free $0/month · Go $8/month · Plus $20/month; monthly USD subscription prices. API usage is billed separately.

Free planFree plan available with 2,000 monthly completions and limited other usage. Student eligibility and free Pro access for eligible teachers/maintainers have separate conditions. A universal current trial duration is not disclosed on reviewed pricing pages.Free access is included with limited model/client availability; Free and Go currently list GPT-6 Luna Standard in desktop, subject to rollout. A universal paid-plan trial duration is not disclosed.

Overview & Compatibility

9 specifications

SpecificationGitHub CopilotOpenAI Codex

Starting PriceFree $0/month · Pro $10/user/month · Business $19/granted seat/month. USD; usage above included allowances is extra.Free $0/month · Go $8/month · Plus $20/month; monthly USD subscription prices. API usage is billed separately.

Tool TypeIDE Assistant / Coding Agent / Code Review; available in editors, terminal, desktop and GitHub.Coding Agent / IDE Assistant; local development and cloud task workflows.

Primary Use CaseComplete and edit code, understand repositories, implement features, generate tests and review pull requests.Implement features, investigate bugs, review changes and automate repository maintenance.

Best ForIndividual developers and engineering teams using GitHub, supported IDEs and repository-based workflows.Individual developers and engineering teams working with repositories, tests and code review.

Access MethodsIDE integrations · Copilot CLI · Copilot desktop app · GitHub.com · GitHub Mobile · SDK. Features differ by surface.Desktop app · CLI · IDE extension/integrations · Web/cloud; mobile cloud access depends on plan and client.

Supported Operating SystemsCLI: Linux, macOS and Windows through PowerShell or WSL. IDE and desktop availability depend on the client.Windows, macOS and Linux; CLI also runs in WSL. Installation, sandboxing and desktop capabilities differ by OS.

Supported IDEs & EditorsVS Code, Visual Studio, JetBrains IDEs, Eclipse and Xcode; Vim/Neovim completion integration is also listed by GitHub. Feature coverage varies.VS Code, VS Code Insiders, Cursor and compatible editors; Xcode and JetBrains offer separate integrations.

Programming LanguagesBroad programming-language support. Quality varies by language and training-data coverage; no equal-capability guarantee.Works across programming languages through source files and installed project tools. No exhaustive language-by-language compatibility guarantee is disclosed.

Framework SupportAssists across many frameworks using source context and project tooling; an exhaustive framework compatibility guarantee is not disclosed.Uses the project’s framework, dependencies and build tools. A complete framework certification/support matrix is not disclosed.

Coding Capabilities

11 specifications

SpecificationGitHub CopilotOpenAI Codex

Code CompletionInline completions and next edit suggestions in supported editors. Free: 2,000 completions/month; paid completions are unlimited, subject to rate limits.Traditional as-you-type inline code autocomplete: Not disclosed. Codex documents prompted coding, editor-context input and diff review.

Code GenerationGenerates functions, implementation code and application changes from prompts; agents can write files and iterate.Generates code and files from instructions in an existing repository or new project.

Inline Code EditingInline chat and suggested edits in supported editors; users can accept proposed changes. Availability depends on IDE.Uses selected editor code and open files as context for requested changes; edits can be reviewed beside the source.

Multi-File EditingAgents can coordinate changes across project files; review diffs before keeping or merging changes.Can change multiple files in one repository task and present the resulting diff for review.

Code ExplanationExplains selected code, project behavior and coding concepts through chat with repository context.Explains repository structure, functions and unfamiliar implementation details using accessible files.

RefactoringCan propose or apply targeted refactors through chat and agents; correctness depends on project context and validation.Refactors existing code using project instructions and can verify the result with available checks.

Debugging AssistanceSuggests fixes and investigates failures using source context and available tools; command execution requires an agent-capable surface.Investigates error reports, traces code paths and implements fixes; available logs and tests improve verification.

Test GenerationGenerates unit tests and additional test suites from code or feature requirements.

Agents & Execution

9 specifications

SpecificationGitHub CopilotOpenAI Codex

Agent Mode & PlanningAsk, Agent and Plan modes in supported IDEs; CLI has planning and execution modes. Administrators can restrict agents.Agent can inspect, plan, edit and verify a task. Planning and execution follow the selected mode and permission policy.

Terminal Command ExecutionCLI and supported IDE agents can execute shell commands with permission controls; cloud agent runs commands in its environment.Runs shell commands, builds and installed development tools within the allowed filesystem and network scope.

Automated Test ExecutionAgents can run project tests and linters when the environment and dependencies are configured; generated tests do not imply successful execution.Runs available test suites, reads failures and can iterate on fixes; dependencies and test infrastructure must be configured.

Browser InteractionCopilot app connects browser workflows; optional computer use in local CLI/app sessions can interact with desktop applications on macOS and Windows. Tools and permissions must be enabled.Built-in interactive browser in the desktop app for sites and local previews. It is not built into Codex CLI or IDE extension; browser tools can be added separately where supported.

Background / Cloud AgentsPaid plans include asynchronous Copilot cloud agent for repository tasks and pull requests. Cloud sandboxes for CLI are public preview.Cloud tasks run in isolated workspaces and continue while the local computer sleeps. Local background work depends on the host remaining available.

Parallel Agent TasksCopilot app manages parallel sessions and repository workstreams; CLI cloud sandboxes support multiple parallel tasks. Capacity depends on available resources and usage.Supports parallel subagents and separate concurrent tasks; Git worktrees help isolate repository changes. Parallel work increases usage.

Human Approval ControlsCLI asks approval for tools that modify or execute files, with session allow/deny options. Agent changes and pull requests remain reviewable; policies vary by surface.

AI Models & Codebase Context

8 specifications

SpecificationGitHub CopilotOpenAI Codex

Supported AI ModelsModel catalog includes GPT-6.1 Sol, GPT-6 Astra/Sol/Luna, Claude Opus 5.5/Sonnet 5.5/Fable 5.1, Gemini 4 Argon, Grok 4.7 and Kimi K3, among others. Access varies by plan, client and policy.GPT-6.1 Sol, GPT-6 Sol, GPT-6 Luna and GPT-6 Astra where eligible. GPT-5.6 variants remain during rollout; model access depends on plan, client and sign-in method.

Model SelectionAutomatic selection and manual model choice on eligible plans/surfaces. Free and Student use Auto; code review does not offer model switching.Configurable defaults plus manual model/reasoning selection via the picker, /model or --model. Available settings depend on client and workspace policy.

Bring Your Own API KeyLocal BYOK in supported clients including VS Code, JetBrains, Xcode, CLI, app and SDK. Enterprise BYOK is public preview and requires licensing and enabled policies.Supports OpenAI API-key authentication in CLI, SDK and IDE workflows. API billing is separate; ChatGPT-dependent cloud features are limited or unavailable with API-key sign-in.

Local Model SupportSupported through compatible local BYOK providers; CLI documents Ollama/vLLM-compatible endpoints. CLI models must support tool calling and streaming.CLI OSS mode supports local providers such as Ollama and LM Studio via --oss. Hardware, model tool support and feature compatibility vary.

Codebase Context & IndexingUses editor/project context and repository information to answer questions and edit files. Indexing and retrieval behavior vary by surface; context access follows permissions and exclusions.Reads and searches accessible repository files, uses editor selections and project guidance. A universal persistent semantic-index specification is not disclosed.

Context WindowDepends on model and client. Selected models offer an optional 1 million-token context in VS Code and Copilot CLI; larger context consumes more AI credits.Model/provider dependent; context usage and compaction affect a session. No single fixed Codex-wide context window is disclosed; API model maximums do not guarantee equivalent usable product context.

Developer Workflow & Integrations

5 specifications

SpecificationGitHub CopilotOpenAI Codex

Git & Pull RequestsGit-aware CLI workflows and native GitHub issues/pull requests; cloud agent can create branches and PRs and revise changes after feedback.Local Git diff, branch/worktree and change-review workflows. Authenticated Git tools/integrations can prepare and create pull requests; remote-provider permissions apply.

MCP & External IntegrationsMCP servers extend supported clients and SDK with external tools and context. Availability and administrative controls vary by client and organization policy.MCP supports external tools and data sources. Plugins and integrations can connect GitHub, GitLab beta, Slack, Linear and other services; availability and permissions differ.

Web SearchCopilot Chat can use Bing web search when enabled; disabled by default in personal settings. Supported IDE workflows expose web search through GitHub skills.Web search is supported, with availability and network behavior determined by client, configuration and workspace policy.

API / SDK AccessCopilot SDK exposes agent sessions, streaming, tools, hooks, custom agents and MCP through the CLI runtime. Programmatic CLI and ACP integrations are also documented.Codex SDKs for TypeScript and Python, app-server for custom clients, and codex exec for automation/CI. Authentication and usage billing follow the chosen runtime.

Deployment SupportCan generate deployment configuration and run permitted deployment tools or GitHub Actions workflows. Hosting is provided by the selected external platform; Copilot is not a standalone managed deployment service.Can run deployment commands or connected tools with permission. Sites adds a build/publish workflow on eligible clients and plans; external hosting has separate credentials and costs.

Pricing, Teams & Security

6 specifications

SpecificationGitHub CopilotOpenAI Codex

Free Plan / TrialFree plan available with 2,000 monthly completions and limited other usage. Student eligibility and free Pro access for eligible teachers/maintainers have separate conditions. A universal current trial duration is not disclosed on reviewed pricing pages.Free access is included with limited model/client availability; Free and Go currently list GPT-6 Luna Standard in desktop, subject to rollout. A universal paid-plan trial duration is not disclosed.

Usage Limits / Extra UsageMonthly included AI credits: Pro 1,500 (1,000 base + 500 flex), Pro+ 7,000 (3,900 + 3,100), Max 20,000 (10,000 + 10,000). Flex amounts can change. Business 1,900/seat and Enterprise 3,900/seat pool across licensed users; extra usage $0.01/credit. Token/model consumption and rate limits apply; Actions usage can add charges.Allowance depends on model, reasoning, speed and task. Plus/Standard Business publish 5-hour estimates; weekly limits may apply. Pro currently has no 5-hour limit. Extra credits and API billing are separate.

Team AdministrationBusiness and Enterprise provide managed seats, policies, usage oversight and organization/enterprise controls. Business $19/seat/month; Enterprise $39/seat/month and requires GitHub Enterprise Cloud.Business/Enterprise provide workspace administration; managed configuration controls Codex access, permissions, models and rollout. Enterprise adds broader governance and audit capabilities.

Code Privacy & Data RetentionHosted requests use GitHub/model-provider infrastructure. Individual Free/Pro/Pro+/Max interactions may train models unless opted out; Business/Enterprise data is not used for training. Business/Enterprise default IDE Chat/completion prompts are not retained; other access retains them for 28 days, with engagement data kept two years. Model-specific retention exceptions and BYOK provider policies apply.Cloud inference processes supplied context unless a local provider is configured. Business/API data is not used for training by default. Retention varies by service, plan and controls; API abuse-monitoring logs are generally retained up to 30 days, with exceptions and eligible ZDR. No universal Codex retention duration is disclosed.