curl quickstart — 5 lines to ship

VerticalAPI is just an HTTP API — you can call it from curl, httpie, Postman or any HTTP client. The endpoint is OpenAI-compatible. Two headers: Authorization for VerticalAPI, X-Provider-Key for the underlying provider.

5-step setup

From zero to first call

Sign up at verticalapi.com/dashboard

Free tier — no card required. Generates your vapi_ key automatically.
Add a provider key

Paste your OpenAI sk-..., Anthropic sk-ant-..., or Google AIza... into the dashboard. Encrypted at rest.
Install the curl SDK

# curl is preinstalled on macOS, Linux and Windows 10+
Run the example below

Drop-in OpenAI SDK pattern — base_url + api_key + provider key header. That's it.
Inspect the trace

Every call gets a unique request ID. Find it in the dashboard with full latency, tokens, and cost breakdown.

Working example

curl — first call

quickstart.curlcurl
curl https://api.verticalapi.com/v1/chat/completions \
  -H "Authorization: Bearer vapi_..." \
  -H "X-Provider-Key: sk-..." \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "messages": [{"role": "user", "content": "Hello, world"}]
  }'

Swap model for claude-sonnet-4-5, gemini-2.5-pro, or any of 25+ supported providers. Update X-Provider-Key to match.

Troubleshooting