Claude Text Generator Webhook with Slack Preview (n8n)

Generate Claude text from an n8n webhook—then preview it in Slack

This n8n workflow exposes a POST webhook that sends your userPrompt to the Anthropic Claude Messages API, returns a consistent JSON response with usage metadata, and automatically posts a short Slack preview of the generated text via a Slack Incoming Webhook.

What this workflow does

• Receives requests: Listens for a POST call on its webhook endpoint with a JSON body containing userPrompt (and optional generation settings).
• Validates inputs: Checks that userPrompt is present and applies defaults for model, maxTokens, and temperature. If validation fails, it returns a 400 JSON error.
• Calls Claude with retries: Sends the prompt to https://api.anthropic.com/v1/messages using the Anthropic Claude Messages API, with automatic retries for transient failures.
• Returns consistent results: On success, extracts the generated text and responds with a 200 JSON payload that includes the generated output plus usage metadata.
• Posts to Slack: After a successful Claude call, publishes a short preview of the generated text to Slack using an Incoming Webhook.
• Error handling: If Claude fails after retries, it returns a structured 502 JSON error to the webhook caller.

Use cases

• SaaS backends that need on-demand Claude text generation triggered by API calls.
• Automation engineers building reliable AI endpoints with validation, retry logic, and clear error responses.
• Teams who want human-readable visibility through a quick Slack preview of what Claude generated.

Technical details

• n8n nodes/workflow logic: webhook, if, set, code, http request, plus workflow notes (sticky note).
• Integrations: Anthropic Claude Messages API (HTTP request to /v1/messages) and Slack Incoming Webhook.
• Setup: Configure an Anthropic API credential in n8n, paste your Slack webhook URL into the workflow, and send POST requests with JSON including userPrompt.