Thanks.io
thanks.io is a direct mail automation platform and API that sends handwritten-style postcards, letters, notecards, gift cards, and MagnaCards on autopilot.
Trusted by 5000+ businesses since 2017, it helps marketers, agencies, realtors, e-commerce brands, and SaaS companies cut through digital noise with physical mail.
Features: proprietary handwriting engine with realistic AI fonts, per-recipient AI messaging, dynamic images, Street View postcards, QR code tracking, scan notifications, and analytics.
Automation: drip campaigns, birthday/holiday triggers, Neighbor Blast radius mailers, evenFLOW paced sending, address verification, suppression lists, and Canva-synced templates.
Developer-first REST API v2 with OpenAPI spec, OAuth2, webhooks, embeddable widget, and LLM-friendly MCP server.
500+ integrations: HubSpot, Salesforce, Shopify, WooCommerce, Zapier, Make, n8n, and 8,000+ apps.
No minimums, no commitments, real free tier, nonprofit rates from $0.45/piece.
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DocuSend
Remotely send your documents directly to the United States Postal Service through our cloud-based mailroom. DocuSend works with any accounting, billing, or CRM software that produces PDF documents containing a valid mailing address. Users can upload directly, or developers can integrate our REST API to offer a "Send Mail" button in their software, either as a reseller or for internal direct connectivity. There are enormous economic advantages for any business or organization that needs to safely print and mail documents on demand. We also offer an automated email service called DocuLink that lets you know which users open the document links sent and makes it easy to follow up with a hard copy if needed. We are sure that one of our features will improve your mailing experience: DocuSend, DocuLink or the Print-To-Mail Rest API will streamline the manual and time-consuming print, mail and email process.
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PostKnock
PostKnock is a marketing platform for small service businesses — dental practices, HVAC contractors, optometrists, chiropractors, veterinary clinics, and home services. It combines direct-mail postcards with automated phone follow-up in a single workflow.
Choose a pre-built industry playbook (dental recall, HVAC seasonal, lapsed-patient re-engagement, etc.), upload a contact list, and PostKnock handles printing, USPS First-Class mailing, QR-code tracking, and post-delivery call queues with pre-loaded scripts for your front desk.
Multi-wave campaigns sequence postcards and calls over weeks. CSV import auto-maps fields. Real-time tracking shows delivery, scans, completed calls, and revenue attribution.
Free plan available — only pay for postcards sent. Pro from $99/month unlocks multi-wave sequencing, the full call queue, and analytics. No contracts. 30-day money-back guarantee.
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Mailjoy
A DIY tool to design, mail, and track personalized postcard and letter campaigns. Surprise your best customers with a special coupon code during your next sale. Reengage customers who've unsubscribed from your product by offering them a discount. Send personalized real estate postcards with data on the property you're mailing to. Delight your target audience by sending them a personalized card. Send personalized direct mail to welcome new customers to your product or service. Reach customers in your next marketing campaign through email and mail simultaneously. Compared to digital channels, mail is an unsaturated channel that until today has been generally inaccessible and lacked personalization. Mailjoy is the tool to reach customers or prospects with mail that's relevant and timely to them. Start by customizing any of our free postcard and letter templates. Mailjoy provides a ton of features to help you create mailing lists from your contacts.
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