Criterion GitHub Copilot OpenAI Codex
CategoryAI Coding AssistantsAI Coding Assistants
In one sentenceAn AI pair programmer and coding agent that works in your editor, terminal and on GitHub itself.OpenAI's coding agent, included with ChatGPT plans and usable with an API key.
Problem it solvesWriting, reviewing and fixing code takes a lot of repetitive effort. Copilot automates routine coding and review work inside the tools developers already use.Engineering backlogs contain many well-defined coding tasks. Codex takes those tasks on so developers can focus on review and design.
Free planYesYes
Developer APINoYes — docs
Open sourceNoNo
PlatformsVS Code, Visual Studio, JetBrains IDEs, Terminal (Copilot CLI), github.comDesktop app, CLI, IDE extension, Web, iOS
Pricing (summary)Copilot Free costs nothing with limited usage. Individual plans are Pro at $10, Pro+ at $39 and Max at $100 per month, each with a monthly AI credit allowance (1 credit = $0.01). Business is $19 and Enterprise $39 per seat per month.
Checked 2026-10-19		Codex is included in ChatGPT Free, Go ($8), Plus ($20), Pro (from $100), Business ($25 per user monthly or $20 annually) and Enterprise/Edu plans. Usage limits rise with the plan. API-key usage is billed separately at standard API token rates.
Checked 2026-10-19
Strengths
  • Deep GitHub integration
  • Wide editor support
  • Multi-model choice on all plans
  • Low entry price
  • Bundled with ChatGPT subscriptions
  • Wide range of models and speed modes
  • Works with API key for local use
Limitations
  • Chat and agent work draws from a credit allowance that varies by model
  • Free tier is limited to 2,000 completions and limited chat/agent use
  • Enterprise controls such as SAML SSO and IP indemnity require Business or Enterprise
  • Usage per 5-hour window is an estimate and varies by model and task
  • Cloud features not available with API key
  • Free and Go tiers are for light use