Postgrid
PostGrid provides APIs for automating direct mail and address verification services, enabling businesses to send letters, postcards, and checks, as well as verify and standardize addresses in real-time.
Verdict
Common use cases
- Send compliance notices to customers automatically
- Mail onboarding packets after signup
- Dispatch checks to vendors from chat
- Track letter delivery via webhook alerts
- Generate templated legal correspondence at scale
Integration
- Vendor
- Postgrid
- Category
- developer-tools
- Auth
- API_KEY
- Tools
- 22
- Composio slug
postgrid
Tools
- CREATE_BANK_ACCOUNT
Tool to create a new bank account for print & mail service.
- Create Contact
Tool to create a new contact in postgrid. use after collecting contact's name, address, and optional metadata.
- Create Letter
Tool to create and send a letter via postgrid. use when recipient, sender, and content details are ready.
- Create Template
Tool to create a new mail template in postgrid. use when you need to define reusable html content with dynamic placeholders. use after confirming required template details.
- Create Webhook
Tool to create a new webhook to receive order event notifications. use after configuring your endpoint to handle webhook payloads.
- Delete Bank Accountdestructive
Tool to delete a bank account by its id. use when you need to remove a bank account after confirming its identifier.
- Delete Contactdestructive
Tool to delete a contact by its id. use when you need to remove obsolete contacts after confirming their identifier.
- Delete Templatedestructive
Tool to delete a template by its id. use when you need to remove an existing template after confirming its identifier.
- Delete Webhookdestructive
Tool to delete a webhook subscription. use when you need to remove an existing webhook by its id.
- Get Bank Account
Tool to retrieve a bank account. use after obtaining the bank account id to fetch its details.
- Get Contact
Tool to retrieve a contact. use after obtaining the contact id to fetch its details.
- Get Letter
Tool to retrieve a letter. use after you have the letter id to fetch its details.
- Get Template
Tool to retrieve a template. use when you have the template id and need its details.
- Get Webhook
Tool to retrieve details of a specific webhook by its id. use after creating a webhook to fetch its configuration and status.
- List Bank Accounts
Tool to list bank accounts. use when retrieving bank accounts with optional status filter and pagination.
- List Cheques
Tool to list cheques with optional filters and pagination. use when you need to retrieve batches of cheque records for processing or reporting.
- List Contacts
Tool to list contacts. use when you need to retrieve a paginated list of contacts with optional filters like date range, metadata, name, or email.
- List Letters
Tool to list letters. use when retrieving letters with optional filters and pagination.
- List Postcards
Tool to retrieve a list of postcards with optional filtering and pagination. use when you need to browse or filter postcards list.
- List Self-Mailers
Tool to list self-mailers. use when you need to fetch self-mailers with filters and pagination.
- List Templates
Tool to list templates. use when you need to retrieve a paginated list of templates with optional type filtering.
- List Webhooks
Tool to retrieve a list of configured webhooks with optional filtering and pagination. use when you need to view your webhooks.
Setup
Setup guide
- 11. Log into your Postgrid dashboard and navigate to Settings → API Keys to generate a new key with full read-write permissions. 2. In Switchy, open your workspace settings and click Integrations → Add MCP → Postgrid. 3. Paste your API key into the authentication field and click Connect. 4. Switchy will verify the key by fetching your account details; you'll see a green checkmark when the connection succeeds. 5. Open any Space and type '@Postgrid list contacts' to confirm the MCP responds with your existing contacts (or an empty list if you're starting fresh). 6. To send your first letter, collect recipient details in chat, then prompt '@Postgrid create a letter to [name] at [address] with body [content]' — the MCP will queue the job and return a tracking ID. 7. Check your Postgrid dashboard to see the letter enter production; delivery typically takes 3-5 business days domestically.
What teammates see: by default, memories from Postgrid are scoped to the Space (PROJECT visibility) - you can mark any memory PRIVATE or share it ORG-wide.
Works well with
Top models
Compatibility data appears once enough Spaces have used this MCP together with a given model.
How Switchy teams use it
Starter prompts
Create Contact Record
@Postgrid create a contact named Jane Doe at 123 Main St, Austin TX 78701 with metadata tags 'customer' and 'tier-premium'.Open in a Space →
Send Letter Now
@Postgrid create a letter to contact ID con_abc123 from our company address with the body 'Your account statement is enclosed. Please remit payment by the 15th.'Open in a Space →
Build Mail Template
@Postgrid create a template named 'Welcome Letter' with HTML body containing placeholders for {{firstName}}, {{accountNumber}}, and {{activationDate}}.Open in a Space →Issue Check Payment
@Postgrid create a check for $1,250.00 payable to Acme Supplies using bank account ID bank_xyz789 and mail to their address on file.Open in a Space →
Set Delivery Webhook
@Postgrid create a webhook pointing to https://our-domain.com/webhooks/postgrid that fires on events 'letter.delivered' and 'letter.returned'.Open in a Space →
Example outputs
Illustrative - representative of the model's voice and quality, not literal recordings.
@Postgrid list all active mail templates we have set up, and show me which ones were used in the last 30 days
Found 8 active templates in your Postgrid account. Three have been used recently: 'Invoice Reminder' (47 sends, last used 2 days ago), 'Welcome Letter' (12 sends, last used 5 days ago), and 'Payment Receipt' (31 sends, last used yesterday). The other 5 templates—'Holiday Card', 'Service Update', 'Contract Renewal', 'Thank You Note', and 'Onboarding Packet'—have not been used in the past 30 days. Each template includes HTML content with merge fields for personalization. This example illustrates typical template inventory; your actual list will reflect your account's configured templates and send history.
This read-heavy example demonstrates Postgrid's template management capabilities. Requires API key with read access to templates and order history. Useful for auditing which mail pieces your team actually sends versus templates that may be outdated. The MCP can retrieve template metadata but cannot display full HTML content in a single response.
@Postgrid create a new contact for Sarah Chen at 450 Market St, San Francisco CA 94102, and tag it with customer_id: cust_8472
Created contact 'Sarah Chen' in Postgrid with ID cont_9x4k2m. Address validated and standardized to: 450 Market Street, San Francisco, CA 94102-4703. Added metadata tag 'customer_id: cust_8472' for reference in future mailings. This contact is now available for use in letter, postcard, or check campaigns. Note that Postgrid performs USPS address validation during creation—if the address had been undeliverable, the API would have returned a validation error. This example shows a successful contact creation; actual responses depend on address validity.
This write example shows Postgrid's contact creation with address validation. Requires API key with write permissions. The MCP automatically triggers USPS address standardization, which may modify the input address format. Metadata tags are critical for linking Postgrid contacts to your internal CRM records. Failed address validation will prevent contact creation, so always verify addresses before bulk operations.
@Postgrid draft a payment reminder letter using our 'Invoice Reminder' template, send it to contact cont_9x4k2m, and set the due_date merge field to March 15, 2025
Created letter order let_7h3p9w using template 'Invoice Reminder'. Recipient: Sarah Chen (cont_9x4k2m), 450 Market Street, San Francisco, CA 94102. Merge fields applied: due_date set to 'March 15, 2025'. Letter queued for printing and mailing—expected delivery in 3-5 business days. Postgrid will charge your account $1.23 for this single-page letter. Webhook notifications (if configured) will fire when the letter is printed, mailed, and delivered. This example illustrates the end-to-end flow; actual delivery timing and cost depend on mail class and page count.
This synthesis example combines template retrieval, contact lookup, and letter creation into one workflow. Requires API key with write permissions and sufficient account balance. The MCP triggers real mail production—this is not a sandbox action. Always verify recipient details and merge field values before sending, as physical mail cannot be recalled. Postgrid's webhook system is essential for tracking delivery status in production use.
Use-case deep-dives
When Postgrid beats email for high-value contract renewals
A 6-person B2B SaaS team sends physical invoices to enterprise customers who require paper records for procurement compliance. Postgrid's letter and template tools let you trigger mail from your billing system without touching a printer. The webhook tool confirms delivery, so your AR team knows when to follow up. This works if you're mailing 20-200 invoices per month and your average contract value justifies the $1-2 per letter cost. Below 20 letters, you're faster printing in-house. Above 200, you need Postgrid's bulk API, which this MCP doesn't expose yet. The contact tool keeps addresses current across renewals, so you're not re-entering data every quarter. If your customers accept PDFs, skip this and stay in email.
Physical mail campaigns when Mailchimp fatigue sets in
A 3-person DTC brand runs quarterly win-back campaigns to dormant customers who stopped opening emails. Postgrid's template and contact tools let you design a postcard once, then trigger sends from your CRM when a customer hits 90 days inactive. The bank account tool handles payment for print runs without manual invoicing. This makes sense if you're mailing 100-500 postcards per campaign and your LTV supports the $0.75-1.50 per card cost. Below 100 cards, you're better off with a one-time Vistaprint order. Above 500, you want a dedicated direct mail platform with better segmentation. The webhook confirms delivery, so you can measure lift against your email-only control group. If your brand is digital-native and your customers are under 30, test small first—physical mail response rates vary wildly by demo.
When regulatory mail requirements force your hand
A 10-person fintech startup must mail account disclosures and terms updates to customers in states that require physical delivery for certain financial products. Postgrid's letter tool automates the send when your onboarding flow completes KYC, and the webhook confirms USPS acceptance for your compliance audit trail. The template tool stores your state-specific disclosure variants so you're not rebuilding PDFs every time regs change. This is non-negotiable if you're in lending, insurance, or securities and your legal team says you need proof of mail. The 22 tools suggest Postgrid built this for developer workflows, so expect to write code—there's no Zapier-style UI. If you're mailing under 50 letters per month, the API key setup is overkill; use a manual service like Lob's dashboard. Above 1,000 per month, you need a compliance-focused vendor with certified mail options.
Frequently asked
What does the Postgrid MCP do in Switchy?
It lets your AI agents send physical mail — letters, postcards, checks — through Postgrid's print-and-mail API. Your team can create contacts, templates, and bank accounts, then trigger mailings directly from Switchy conversations. Useful if you're automating customer onboarding packets, compliance notices, or payment disbursements that still require paper.
Do I need a Postgrid account to use this MCP?
Yes. You'll need an active Postgrid account and an API key with write permissions. Postgrid charges per piece of mail sent, so connect a production key only after you've tested in their sandbox environment. The MCP authenticates with that key; no OAuth dance required.
Can the Postgrid MCP track delivery status of sent mail?
Not directly through the listed tools. The MCP can create webhooks to receive event notifications from Postgrid, but you'll need to configure an endpoint on your side to capture delivery updates. For one-off status checks, query Postgrid's dashboard or use their REST API outside Switchy.
Why use this MCP instead of calling Postgrid's API myself?
The MCP wraps Postgrid's API so your AI agents can send mail without you writing integration code. If you're already piping data through Switchy workflows — say, contract signatures trigger welcome kits — the MCP keeps everything in one place. For bulk campaigns or complex routing logic, Postgrid's native API gives you more control.
Who on my team should connect the Postgrid MCP?
Whoever owns your mail automation budget and has access to Postgrid API keys — typically ops or finance. They'll paste the key into Switchy once; after that, any team member with workspace access can ask an agent to send mail. Just remember: every letter costs real money, so set usage guardrails.