[Automation integration]

Give n8n agents and workflows postal mail tools

Use n8n when you want self-hosted workflow control: let AI Agent or HTTP nodes decide when postal mail is needed, call mailbox.bot, then branch on delivery events, forwarded documents, or inbound mail photos.

recommended shape

AI Agent or HTTP node trigger

letter or PDF built in the graph

dry_run=true via HTTP Request

approval branch gates the send

Webhook node branches on events

Best for

Agent workflows that need tool calls instead of hard-coded SaaS connectors.

Self-hosted operations teams wiring CRM, email, forms, document generation, and OCR pipelines.

Teams that want to branch deeply on mailbox.bot outbound and inbound events inside one workflow graph.

Triggers

n8n AI Agent decides postal mail is required.

Webhook receives a form, CRM, invoice, or permit event.

Scheduled job checks records needing certified mail.

[Workflow]

1

n8n collects source data and creates the letter or PDF.

2

Agent or HTTP node calls mailbox.bot dry_run=true.

3

Approval branch confirms live send.

4

mailbox.bot sends mail and posts webhooks to n8n.

5

n8n updates the original app, processes forwarded inbound artifacts when they arrive, and continues the workflow.

Technical pattern

AI Agent node with the MCP Client Tool pointed at https://mailbox.bot/api/mcp, or an HTTP Request node for a deterministic send.

A Wait node holds the workflow for approval and resumes on a webhook or form submission.

A Webhook node receives mail events; a Switch on event_type branches the graph.

Keep workflow_id and execution_id in metadata to correlate resumed executions.

Metadata to preserve

source=n8n

workflow_id

execution_id

source_system

source_record_id

approval_node

POST/api/v1/maildry_run=true

curl -X POST https://mailbox.bot/api/v1/mail \
  -H "Authorization: Bearer sk_agent_test_..." \
  -H "X-Mailbox-MD-Version: <version>" \
  -H "X-Max-Cost-Cents: 2500" \
  -F "document=@workflow-letter.pdf" \
  -F "recipient_name=<recipient>" \
  -F "recipient_line1=<street>" \
  -F "recipient_city=<city>" \
  -F "recipient_state=<state>" \
  -F "recipient_zip=<zip>" \
  -F "mail_class=certified" \
  -F "dry_run=true" \
  -F 'metadata[workflow_id]=<workflow_id>' \
  -F 'metadata[execution_id]=<execution_id>' \
  -F 'metadata[source_system]=<source_system>' \
  -F 'metadata[source]=n8n'

Agent prompts

"Build an n8n agent workflow that turns an ignored email thread into a mailbox.bot certified mail draft."

"Use mailbox.bot MCP in n8n to preview a permit follow-up letter, require approval, then send."