DeadAI Dev Tools

OpenAI Codex (code model)

by OpenAI

Announced

2023-03-21

Complete

2023-03-23

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Refund status

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OpenAI Codex was the code-specialised model that originally powered GitHub Copilot (2021-2023). On March 21, 2023, OpenAI announced the discontinuation of the standalone Codex API, with shutdown two days later. The model was deprecated because GPT-3.5 and GPT-4 had become competitive at code generation while being more capable for general tasks — a single model became cheaper than maintaining two. GitHub Copilot itself continued operating; only the standalone Codex API was deprecated.

Refund flow

1
Not applicable. Codex was free during its public preview / pay-per-token after that — no pre-paid credits.

Migration path

Recommended successor

GPT-4 Turbo or GPT-4o for code generation; GitHub Copilot for IDE integration

Why this is the closest fit

GPT-4 family is the direct successor for code-generation API use. GitHub Copilot is the productised IDE-integrated version that originally relied on Codex but has since moved to GPT-4 family models.

What differs from the original

GPT-4 is more general-purpose but the code-specific tuning that made Codex efficient on code tokens specifically is gone. Higher cost per token than Codex was. For pure code-completion use cases, the specialisation gap has been mostly closed by GPT-4 scale.

What this tool meant

Codex was the breakthrough model that proved AI could write meaningful code, not just autocomplete a few tokens. Released in 2021 (after the original Codex paper), it powered the first GitHub Copilot release. The 2023 deprecation marked the transition from specialised models (one per task) to general-purpose models (GPT-4 + careful prompting). The pattern repeats across AI: specialised models give way to scaled general models as the general models become competitive enough to amortise their cost across more use cases.