n8n-nodes-gmail-custom

Self-contained n8n nodes for Gmail API via Google service accounts with domain-wide delegation. No n8n credential setup — all parameters inline, supports expressions.

Nodes

| Node | Description | |---|---| | Gmail Custom | Send emails via Gmail API | | Gmail Trigger Custom | Poll Gmail for new messages | | Gmail Get Custom | Get a single Message or Thread by ID |

All three share the same token cache — only 1 oauth call per hour across all nodes.

Installation

In n8n: Settings → Community Nodes → Install → n8n-nodes-gmail-custom

Gmail Custom (Send)

Sends an email via Gmail API. Supports HTML/text body, CC, BCC, Reply-To, attachments (with graceful skip), sender name, and optional custom Message-ID.

| Field | Description | |---|---| | Service Account Email | SA client_email (JWT iss) | | Private Key | RSA PEM key (hidden) | | From Email | User to impersonate via DWD (JWT sub) | | To | Recipient(s), comma-separated | | Subject | Email subject | | Email Type | HTML or Text | | Message | Email body |

Options: CC, BCC, Reply-To, Sender Name, Attachments (binary data), Custom Message-ID (auto-generated <uuid@domain> if empty).

Output: { id, threadId, labelIds, messageId } (messageId only when Custom Message-ID enabled).

Gmail Trigger Custom (Polling)

Polls Gmail inbox and returns new messages. Emails fetched in format: raw (single API call) and parsed via mailparser.

| Field | Description | |---|---| | Service Account Email | SA client_email | | Private Key | RSA PEM key | | Delegated Email | Mailbox to monitor | | Simplify | true = parsed output, false = raw Gmail API response | | Max Emails per Poll | 1–50, excess queued for next poll | | Mark as Read | Optional: marks processed emails as read (+1 API call) |

Filters: Include Spam/Trash, Include Drafts, Label IDs, Search query, Read Status, Sender.

Options: Download Attachments, Attachment Prefix (binary property name).

Output (simple: true): { id, threadId, labelIds, snippet, from, to, subject, date, messageId, html, text, attachments: [{filename, contentType, size}] }

Output (simple: false): Raw Gmail API response { id, threadId, labelIds, payload: { headers: [...] }, raw: "base64..." }

Gmail Get Custom (Message / Thread)

Retrieves a single message or thread by ID.

| Field | Description | |---|---| | Service Account Email | SA client_email | | Private Key | RSA PEM key | | Delegated Email | Mailbox to access | | Resource | Message or Thread | | Message ID / Thread ID | The Gmail ID to retrieve | | Simplify | true = parsed, false = raw |

Options: Return Only Messages (Thread only), Download Attachments (Message only), Attachment Prefix.

Get Message output (simple: true): { id, threadId, labelIds, snippet, from, to, subject, date, messageId, html, text, attachments }

Get Message output (simple: false): Raw Gmail API response

Get Thread output (simple: true): { id, historyId, messages: [{ id, from, to, subject, ... }, ...] } — headers flattened per message

Token caching

Access token is cached in-memory for 58 minutes (3500s). Cache key: ${serviceAccountEmail}:${delegatedEmail}. Shared across all three nodes.

License

MIT