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Pro plan. Claude works through a connection and HTTP steps, which are part of Pro and Agency (and the free trial). Anything you already have keeps working on every plan. See Plans and billing.
A Webhook / HTTP step sends the contact’s title, headline and company description to Claude with your prompt, for example to rate their fit in one word. A Condition then branches on Claude’s answer. Kerux’s own AI features (reply types, Ask AI, Reply with AI) use Kerux’s AI credits. This guide is for teams that want their own Anthropic key, model choice and prompts.
How it connects: Anthropic’s API with your key in the x-api-key header and an anthropic-version header. See Anthropic’s Messages API docs. The model id is yours to choose from Anthropic’s docs.

Before you start

  • Anthropic billing: the API is billed per token on your Anthropic account, separately from Claude.ai plans.
  • An API key: create one in the Anthropic Console.

1. Connect Anthropic

In Kerux, open Integrations > Connections, click Connect on Custom API (under Developers):
  • How it signs in: API key in a header, Header name x-api-key, paste the key.
  • Base URL: https://api.anthropic.com
Click Save.

2. Rate the fit

After Invitation accepted, add a Webhook / HTTP step named claude:
Claude answers (trimmed):
The answer is {{steps.claude.response.body.content.0.text}}. Add a Condition on it: strong notifies the owner, weak gets a lighter sequence. Add tags records the fit on the contact. Kerux already sorts replies by itself (reply types), so you don’t need Claude for that.

Test with one contact

In the Builder, click Test to open Test on one contact. The journey shows the request and Claude’s answer.

Common errors

The key is wrong or the header name isn’t x-api-key.
A required field is missing (model, max_tokens, messages) or the model id is wrong. The message says which.
Rate limit or overload on Anthropic’s side. Kerux retries later on its own.
Related: Webhook steps, OpenAI, n8n.