This Claude tutorial focuses only on Claude Code: from installation to first run, API key binding, account switching, subscriptions, and troubleshooting common errors. Follow the steps to get Claude Code running in your local terminal. The commands in this article apply to Windows/macOS/Linux. I’ll try to call out the common pitfalls upfront so you can avoid detours.
1) Installing Claude Code: environment setup and first run
Claude Code depends on Node.js. It’s recommended to install Node.js 18 or later and confirm that npm works in your terminal. Then perform a global installation:
npm install -g @anthropic-ai/claude-code
After installation, use
claude --version
to check whether it prints a version number.
When you run Claude Code for the first time, it will usually prompt you to configure your Anthropic API key. You can also set the environment variable ANTHROPIC_API_KEY in advance and then start Claude Code to avoid re-entering it.
2) Account binding and switching: managing with API keys is the easiest
The core of “logging in” to Claude Code is API key binding: one key corresponds to a billing and permission source. If you want to switch accounts, the most reliable approach is to change ANTHROPIC_API_KEY (or replace the key in the configuration file generated on Claude Code’s first run; the specific path will be shown during initialization).
If you switch between a company account and a personal account, it’s recommended to set environment variables separately for different terminal sessions, avoiding hard-coding the key in global configuration to reduce misuse and leakage risk.
3) Plan differences and how to save money: choose based on your use case
Common Claude subscriptions include Pro and Max (prices and benefits may change per official updates), which are better suited for high-frequency conversations on the web. For Claude Code, costs more commonly come from API usage volume. For developers, batching large tasks into one or two days and making only small tweaks the rest of the time is often more economical than “keeping it on at high frequency long-term.”
If users in China run into payment or network restrictions, prioritize compliant API payment channels or enterprise/team consolidated billing. Using keys from unknown sources is not recommended, as it can easily trigger risk controls and cause Claude Code to be interrupted midway.
4) Common issues and error troubleshooting: subscription failures, request errors, account lockouts
Subscription failures often occur due to mismatches in payment method, region, or billing information. First check 3DS verification on the card, billing address, and currency support. If you only use Claude Code, confirm whether you actually need a subscription, or whether you only need a working API key and quota.
Request errors (such as timeouts/interruptions) are usually caused by unstable network conditions, excessive concurrency, or overly long context. Recommended handling order: switch to a more stable network → reduce the amount of input and scope of changes in one go → have Claude Code proceed step by step (analyze first, then modify, then test).
If an account is locked or a key becomes invalid, first check in the console whether the key has been revoked, whether your quota has been exhausted, and whether abnormal usage has been triggered. After switching to a new API key, restarting Claude Code usually restores it. If errors persist, then check whether a local proxy/certificate interception is involved and whether the system time is correct.
