Postmark Automation via Rube MCP
Automate Postmark transactional email operations through Composio's Postmark toolkit via Rube MCP.
Toolkit docs: composio.dev/toolkits/postmark
Prerequisites
- Rube MCP must be connected (RUBE_SEARCH_TOOLS available)
- Active Postmark connection via
RUBE_MANAGE_CONNECTIONSwith toolkitpostmark - Always call
RUBE_SEARCH_TOOLSfirst to get current tool schemas
Setup
Get Rube MCP: Add https://rube.app/mcp as an MCP server in your client configuration. No API keys needed — just add the endpoint and it works.
- Verify Rube MCP is available by confirming
RUBE_SEARCH_TOOLSresponds - Call
RUBE_MANAGE_CONNECTIONSwith toolkitpostmark - If connection is not ACTIVE, follow the returned auth link to complete Postmark authentication
- Confirm connection status shows ACTIVE before running any workflows
Core Workflows
1. Send Templated Batch Emails
When to use: User wants to send templated emails to multiple recipients in one call
Tool sequence:
POSTMARK_LIST_TEMPLATES- Find available templates and their IDs [Prerequisite]POSTMARK_VALIDATE_TEMPLATE- Validate template with model data before sending [Optional]POSTMARK_SEND_BATCH_WITH_TEMPLATES- Send batch emails using a template [Required]
Key parameters:
TemplateIdorTemplateAlias: Identifier for the template to useMessages: Array of message objects withFrom,To,TemplateModelTemplateModel: Key-value pairs matching template variables
Pitfalls:
- Maximum 500 messages per batch call
- Either
TemplateIdorTemplateAliasis required, not both TemplateModelkeys must match template variable names exactly (case-sensitive)- Sender address must be a verified Sender Signature or from a verified domain
2. Manage Email Templates
When to use: User wants to create, edit, or inspect email templates
Tool sequence:
POSTMARK_LIST_TEMPLATES- List all templates with IDs and names [Required]POSTMARK_GET_TEMPLATE- Get full template details including HTML/text body [Optional]POSTMARK_EDIT_TEMPLATE- Update template content or settings [Optional]POSTMARK_VALIDATE_TEMPLATE- Test template rendering with sample data [Optional]
Key parameters:
TemplateId: Numeric template ID for GET/EDIT operationsName: Template display nameSubject: Email subject line (supports template variables)HtmlBody: HTML content of the templateTextBody: Plain text fallback contentTemplateType: 'Standard' or 'Layout'
Pitfalls:
- Template IDs are numeric integers, not strings
- Editing a template replaces the entire content; include all fields you want to keep
- Layout templates wrap Standard templates; changing a layout affects all linked templates
- Validate before sending to catch missing variables early
3. Monitor Delivery Statistics
When to use: User wants to check email delivery health, open/click rates, or outbound overview
Tool sequence:
POSTMARK_GET_DELIVERY_STATS- Get bounce counts by type [Required]POSTMARK_GET_OUTBOUND_OVERVIEW- Get sent/opened/clicked/bounced summary [Required]POSTMARK_GET_TRACKED_EMAIL_COUNTS- Get tracked email volume over time [Optional]
Key parameters:
fromdate: Start date for filtering stats (YYYY-MM-DD)todate: End date for filtering stats (YYYY-MM-DD)tag: Filter stats by message tagmessagestreamid: Filter by message stream (e.g., 'outbound', 'broadcast')
Pitfalls:
- Date parameters use YYYY-MM-DD format without time component
- Stats are aggregated; individual message tracking requires separate API calls
messagestreamiddefaults to all streams if not specified
4. Manage Bounces and Complaints
When to use: User wants to review bounced emails or spam complaints
Tool sequence:
POSTMARK_GET_BOUNCES- List bounced messages with details [Required]POSTMARK_GET_SPAM_COMPLAINTS- List spam complaint records [Optional]POSTMARK_GET_DELIVERY_STATS- Get bounce summary counts [Optional]
Key parameters:
count: Number of records to return per pageoffset: Pagination offset for resultstype: Bounce type filter (e.g., 'HardBounce', 'SoftBounce', 'SpamNotification')fromdate/todate: Date range filtersemailFilter: Filter by recipient email address
Pitfalls:
- Bounce types include: HardBounce, SoftBounce, SpamNotification, SpamComplaint, Transient, and others
- Hard bounces indicate permanent delivery failures; these addresses should be removed
- Spam complaints affect sender reputation; monitor regularly
- Pagination uses
countandoffset, not page tokens
5. Configure Server Settings
When to use: User wants to view or modify Postmark server configuration
Tool sequence:
POSTMARK_GET_SERVER- Retrieve current server settings [Required]POSTMARK_EDIT_SERVER- Update server configuration [Optional]
Key parameters:
Name: Server display nameSmtpApiActivated: Enable/disable SMTP API accessBounceHookUrl: Webhook URL for bounce notificationsInboundHookUrl: Webhook URL for inbound email processingTrackOpens: Enable/disable open trackingTrackLinks: Link tracking mode ('None', 'HtmlAndText', 'HtmlOnly', 'TextOnly')
Pitfalls:
- Server edits affect all messages sent through that server
- Webhook URLs must be publicly accessible HTTPS endpoints
- Changing
SmtpApiActivatedaffects SMTP relay access immediately - Track settings apply to future messages only, not retroactively
Common Patterns
Template Variable Resolution
1. Call POSTMARK_GET_TEMPLATE with TemplateId
2. Inspect HtmlBody/TextBody for {{variable}} placeholders
3. Build TemplateModel dict with matching keys
4. Call POSTMARK_VALIDATE_TEMPLATE to verify rendering
Pagination
- Set
countfor results per page (varies by endpoint) - Use
offsetto skip previously fetched results - Increment offset by count each page until results returned < count
- Total records may be returned in response metadata
Known Pitfalls
Authentication:
- Postmark uses server-level API tokens, not account-level
- Each server has its own token; ensure correct server context
- Sender addresses must be verified Sender Signatures or from verified domains
Rate Limits:
- Batch send limited to 500 messages per call
- API rate limits vary by endpoint; implement backoff on 429 responses
Response Parsing:
- Response data may be nested under
dataordata.data - Parse defensively with fallback patterns
- Template IDs are always numeric integers
Quick Reference
| Task | Tool Slug | Key Params | |------|-----------|------------| | Send batch templated emails | POSTMARK_SEND_BATCH_WITH_TEMPLATES | Messages, TemplateId/TemplateAlias | | List templates | POSTMARK_LIST_TEMPLATES | Count, Offset, TemplateType | | Get template details | POSTMARK_GET_TEMPLATE | TemplateId | | Edit template | POSTMARK_EDIT_TEMPLATE | TemplateId, Name, Subject, HtmlBody | | Validate template | POSTMARK_VALIDATE_TEMPLATE | TemplateId, TemplateModel | | Delivery stats | POSTMARK_GET_DELIVERY_STATS | (none or date filters) | | Outbound overview | POSTMARK_GET_OUTBOUND_OVERVIEW | fromdate, todate, tag | | Get bounces | POSTMARK_GET_BOUNCES | count, offset, type, emailFilter | | Get spam complaints | POSTMARK_GET_SPAM_COMPLAINTS | count, offset, fromdate, todate | | Tracked email counts | POSTMARK_GET_TRACKED_EMAIL_COUNTS | fromdate, todate, tag | | Get server config | POSTMARK_GET_SERVER | (none) | | Edit server config | POSTMARK_EDIT_SERVER | Name, TrackOpens, TrackLinks |
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