Skip to main content

Documentation Index

Fetch the complete documentation index at: https://docs.fortapi.com/llms.txt

Use this file to discover all available pages before exploring further.

Claude Code is Anthropic’s official command-line coding assistant. It hits api.anthropic.com by default — set ANTHROPIC_BASE_URL to point it at FortAPI instead, no proxy layer required.
This page covers direct setup. If you’d rather manage multiple providers in a GUI, see CC Switch.

​
Prerequisites

1

FortAPI API key

Console → Tokens → Create token to get a sk-... string. See API keys & security.
2

Node.js ≥ 18

Claude Code needs Node.js 18+. Check with:
node --version
If missing, grab the LTS from nodejs.org, or on macOS:
brew install node

​
Install Claude Code

npm install -g @anthropic-ai/claude-code
Confirm:
claude --version

​
Point Claude Code at FortAPI

Three configuration methods, in order of preference: Edit ~/.claude/settings.json (macOS / Linux) or %USERPROFILE%\.claude\settings.json (Windows). Create it if missing: 
{
  "env": {
    "ANTHROPIC_BASE_URL": "https://www.fortapi.com",
    "ANTHROPIC_API_KEY": "sk-your-FortAPI-token",
    "ANTHROPIC_MODEL": "claude-sonnet-4-6",
    "ANTHROPIC_SMALL_FAST_MODEL": "claude-haiku-4-5"
  }
}
Do not append /v1 to ANTHROPIC_BASE_URL. The Anthropic SDK adds /v1/messages itself, and an extra /v1 causes 404s.
FieldMeaning
ANTHROPIC_BASE_URLThe FortAPI endpoint
ANTHROPIC_API_KEYYour FortAPI token (not the official Anthropic key)
ANTHROPIC_MODELDefault Claude model. claude-sonnet-4-6 is the best price/performance balance
ANTHROPIC_SMALL_FAST_MODELTiny model Claude Code uses for internal tasks (title generation, path completion) — claude-haiku-4-5 keeps costs low

​
Method 2: shell env vars

For a quick trial: 
export ANTHROPIC_BASE_URL="https://www.fortapi.com"
export ANTHROPIC_API_KEY="sk-your-key"
claude
Add the same lines to ~/.zshrc or ~/.bashrc to make them permanent.

​
Method 3: use CC Switch

If you bounce between FortAPI and your official account, install CC Switch and manage providers from a GUI.

​
First call

Open a new terminal (so env vars are loaded), cd into any project: 
cd ~/some-project
claude
In the interactive prompt, ask the simplest possible thing: 
> Reply with one English sentence: hello
You should get an immediate Claude reply, and the FortAPI Console → Logs should show the request with a token-level cost line.
To double-check the call really went through FortAPI, open FortAPI Console → Logs and look at the newest entry — the model name should match claude-sonnet-4-6 (or whatever you configured).

​
Switch models on the fly

Inside a session: 
/model claude-opus-4-7
/model claude-haiku-4-5
Full model list at the model gallery.

​
Troubleshooting

  • ANTHROPIC_API_KEY must be your FortAPI token (sk-...), not Anthropic’s sk-ant-....
  • Watch for trailing whitespace or line breaks when copying.
  • In FortAPI Console → Tokens, confirm the key is enabled and that the model allowlist (if any) doesn’t exclude the model you’re calling.
  • Typo in the model ID. Claude model names on FortAPI match Anthropic’s official IDs: claude-sonnet-4-6, claude-opus-4-7, claude-haiku-4-5.
  • Don’t add /v1 to ANTHROPIC_BASE_URL.
Check USD balance on the Console home page. Long-context conversations and tool calls burn tokens fast.
  • Verify reachability: curl -I https://www.fortapi.com
  • If you’re behind a corporate proxy, make sure HTTPS_PROXY isn’t routing to a dead endpoint.
  • No VPN required.
Use CC Switch for one-click toggling, or direnv to bind different env vars per project directory.

​
Advanced

  • MCP servers: independent of which backend API you use — configure as usual.
  • Tool calls / function calling: FortAPI forwards Anthropic’s tool calls unchanged.
  • Streaming / SSE: on by default, nothing extra to configure.
For more Claude Code tips, see the official documentation.