Connect Codex to DeepSeek-V4-Flash (2026)｜One-Click CLI Script + CC Switch, Step by Step
DeepSeek-V4-Flash is fast and its agent capabilities are noticeably stronger than the previous generation. The good news: DeepSeek officially provides a one-click script to connect it to Codex — no code changes, no hand-written config files. Run one command, paste your API Key, done.
And you only configure it once: Codex CLI, the desktop app, and IDE extensions all pick it up.
Contents:
- What Is DeepSeek-V4-Flash?
- What to Prepare Before You Start
- Method 1. Official One-Click Script
- Method 2. CC Switch GUI
- Verify the Configuration
- FAQ
What Is DeepSeek-V4-Flash?
DeepSeek-V4-Flash is DeepSeek's fast-tier model, built for speed. Compared with V4-Pro Preview, its agent capabilities are noticeably stronger, which makes it a good fit for autonomous coding agents like Codex — reading code, editing files, and running tests.
Once connected, Codex's underlying model becomes DeepSeek-V4-Flash: you keep the familiar Codex interface, but the heavy lifting is done by DeepSeek.
What to Prepare Before You Start
- ☐ Codex CLI 0.144.0 or newer: older versions won't recognize DeepSeek's official model catalog
- ☐ A DeepSeek account and API Key: create the key on the DeepSeek platform
- ☐ A terminal with internet access: Terminal on macOS/Linux, PowerShell on Windows
First, Check the Codex CLI Version
Run this in your terminal:
codex --version
DeepSeek's official model catalog requires Codex CLI 0.144.0 or newer. If yours is older, update first:
codex updateMethod 1. Official One-Click Script
The official one-click script is the recommended way — just three steps: run the script → pick 1 → paste your API Key.
macOS and Linux
Run in your terminal:
bash <(curl -fsSL https://cdn.deepseek.com/api-docs/codex-deepseek-setup.sh)Windows
Run in PowerShell:
irm https://cdn.deepseek.com/api-docs/codex-deepseek-setup-en.ps1 | iexThe demo below uses Windows. After the script runs, DeepSeek asks what you want to do:
To connect the latest DeepSeek-V4-Flash, pick 1:
The script then asks for your API Key — paste the one you created on the DeepSeek platform and press Enter:
That's it — the connection is done:
Method 2. CC Switch GUI
Don't want to touch the command line? Use CC Switch, a GUI tool that switches model providers right inside the Codex desktop app (ChatGPT desktop).
- Open CC Switch and select the Codex tab
- Click + to add a provider, choose the DeepSeek preset, fill in your API Key, and pick DeepSeek-V4-Flash
- In Advanced Options, the upstream format defaults to routing, which is fine. If you'd rather not use routing, pick Native — but you'll need CC Switch newer than v3.19.1 to see that advanced option.
- Save, then fully quit and restart Codex (ChatGPT desktop). If you see DeepSeek in the bottom-left corner after restarting, the config is working.
Verify the Configuration
In Codex CLI, type:
/modelIf DeepSeek V4 Flash appears in the model list, the connection is live.
Pros and Cons
Advantages of the two connection methods
- Official one-click script: one command + paste your API Key, about 3 minutes, zero code — for command-line users
- CC Switch: a GUI where you click to switch models in the desktop app — for people who don't want to touch a terminal
- Configure once, works everywhere: Codex CLI, the desktop app, and IDE extensions share the same config
Limitations / things to note
- Codex CLI must be 0.144.0+ — older versions can't recognize the official model catalog
- You need to create and fund an API Key on the DeepSeek platform first, or nothing will connect
- Depends on a stable network; watch your proxy config when reaching DeepSeek / Codex from within China
Who It's For
- Developers who want Codex running on DeepSeek-V4-Flash for speed and cost
- Command-line users who want the official one-click script
- Desktop-app users who prefer a GUI and want to switch model providers anytime
FAQ
Q: What version of Codex do I need to connect DeepSeek-V4-Flash? A: Codex CLI 0.144.0 or newer. If yours is older, run codex update first — otherwise DeepSeek's official model catalog won't be recognized.
Q: What's the official one-click setup command? A: macOS/Linux: bash <(curl -fsSL https://cdn.deepseek.com/api-docs/codex-deepseek-setup.sh). Windows PowerShell: irm https://cdn.deepseek.com/api-docs/codex-deepseek-setup-en.ps1 | iex.
Q: After one setup, which Codex clients can use it? A: Codex CLI, the desktop app, and IDE extensions. One setup is shared by every Codex client form.
Q: How do I confirm DeepSeek-V4-Flash is connected? A: Type /model in Codex CLI — if DeepSeek V4 Flash appears in the list, it's connected. With CC Switch, fully restart Codex and check for "DeepSeek" in the bottom-left corner.
Q: CC Switch upstream format: routed or native? A: The default routed mode is fine. Choose Native only if you don't want routing, and you need CC Switch newer than v3.19.1 for that advanced option.
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