n8n Workflow: Translate LINE Chats to Slack with Claude

Translate LINE chat messages into Japanese for Slack—then translate staff replies back (safely) with Claude

This n8n workflow automatically routes LINE customer messages into Slack for Japanese-speaking staff, using Anthropic Claude to detect the customer’s language and translate both directions—while validating numbers, URLs, and emails to reduce risky translation mistakes.

What this workflow does

• Receives LINE webhook events, verifies the LINE signature, and deduplicates any redelivered events.
• Filters input to text messages only, ignoring non-text content.
• Uses Anthropic Claude to:
  • Detect the customer’s language
  • Translate the message into Japanese
  • Create an acknowledgment in the customer’s language
• Sends the acknowledgment back via the LINE Messaging API.
• Posts to Slack in an existing customer thread or creates a new thread, then stores/updates the mapping (thread and language) in an n8n Data Table.
• Listens for Slack staff replies and processes only human messages inside the existing customer thread (excludes bot posts and messages prefixed with //).
• Finds the matching customer record by Slack thread timestamp, translates the staff reply to the customer’s language if needed, and validates that numbers, URLs, and emails in the Japanese reply appear in the translation.
• If validation fails, it posts a Slack warning and stops; otherwise it performs a blind back-translation of the sent text to Japanese for review, then sends the final message back through the LINE Messaging API.

Use cases

• Support teams handling international LINE inquiries with a Japanese-first internal workflow in Slack.
• SaaS operators needing automated bilingual chat routing with safeguards around links, contact info, and numeric data.
• Reducing manual translation work while keeping staff in control of the final Japanese source text.

Technical details

• Integrations/nodes: LINE webhook + LINE Messaging API, Slack, Anthropic Claude
• n8n logic: if, set, code, no op, slack, crypto
• Data handling: stores thread/language mapping in an n8n Data Table