Use Claude Code with a cheap API: setup in 3 minutes

Claude Code burns through tokens fast — paying the official per-token USD rates makes a serious coding session add up quickly. The cheaper route: point Claude Code at the Cho Tai Khoan API gateway, pay a fixed package from $0.72 (≈ 19.000đ), and use one key across 26 models.

Do not have Claude Code yet? Install it first (about 1 minute)

1. Install the LTS version of Node.js from nodejs.org (skip this if your machine already has Node.js).
2. Open Terminal (macOS / Linux) or PowerShell (Windows) and run:

npm install -g @anthropic-ai/claude-code

Windows users should also install Git for Windows from git-scm.com (remember to tick "Add to PATH") so Claude Code can use Bash commands like most online guides assume; without it, PowerShell still works.

Check the install: run claude --version — a version number means you are good.

Step 1 — Get a key first

1. Go to the API gateway home page and pick a package (if you are just trying it out, the Starter package at $0.72 is enough to install and test every app).
2. Pay by USDT, VietQR bank transfer or MoMo — the system issues a redeem code automatically.
3. Redeem the code right on the page and you receive a key starting with sk-ctk-. Keep this key safe.

Step 2 — Point Claude Code at the gateway

You only need to add 2 lines of configuration so Claude Code calls through the gateway instead of calling the provider directly:

Open a command window: on Windows press Start, type PowerShell, press Enter. On macOS press Cmd + Space, type Terminal, press Enter.

If you have already checked your key on the home page in the same browser, the key in the boxes below is already filled in for you — just copy them as-is, no manual editing.

macOS / Linux — add to your ~/.zshrc file (or ~/.bashrc):

export ANTHROPIC_BASE_URL="https://api.chotaikhoan.com"
export ANTHROPIC_AUTH_TOKEN="KEY_CUA_BAN"

Windows — open PowerShell and run these 2 commands:

setx ANTHROPIC_BASE_URL "https://api.chotaikhoan.com"
setx ANTHROPIC_AUTH_TOKEN "KEY_CUA_BAN"

Replace KEY_CUA_BAN with your sk-ctk-... key. Then fully close and reopen Claude Code (and its terminal window) so it picks up the new configuration.

Step 3 — Check with the "magic sentence"

In Claude Code, type exactly: "Reply with exactly one word: running". If the app answers "running", you are running through the gateway. From now on, every use is charged against your package quota — open the Check key section on the home page to see exactly how much each call charged, split by input / output / cache tokens.

Common errors

• Invalid key error: usually a missing character or an extra space at the start/end when copying. Copy the key again — never type it by hand.
• Empty or cut-off replies: your app has max_tokens set too low — raise it to 500 or more.
• Out of quota: redeem another code on the Redeem page — the quota stacks onto your old key, validity follows the new package, and there is no need to set anything up again.
• System busy: a temporary error on our side, and that request was not charged. Wait a few minutes and try again.