How to Leverage Letterstream’s API to Send Mail Online

LetterStream’s API helps businesses automate sending mail online.

Still uploading spreadsheets and manually sending documents through a dashboard?

If your systems can talk to each other—but your mail still depends on someone hitting “print”—you’re leaving time, accuracy, and efficiency on the table.

Modern businesses aren’t just adopting digital tools. They’re connecting them. And if you’re still managing physical mail as a separate, manual process, it might be time to bring it into the fold—through automation.

That’s where the LetterStream API comes in.

Meet the LetterStream API: Built for Real Business Workflows

Our Application Programming Interface (API) allows you to trigger physical mail jobs—First-Class, and Certified Mail—directly from your own systems. No more logging in. No more uploading. Just a clean, secure handoff from your database or CRM to the mailbox.

In other words: your software sends the job. LetterStream handles the rest.

Use cases include:

  • Triggering Certified Mail when a case status changes in your legal software
  • Automatically mailing statements from your billing platform each month
  • Sending notices from your internal tools without needing a dashboard or admin

It’s the kind of automation that turns “How do we send this?” into “It’s already sent.”

What Can You Automate with the LetterStream API?

Once integrated, the API allows you to:

  • Create mailing jobs in real time
  • Upload PDFs and addresses directly from your system
  • Specify mail class (First-Class, and Certified Mail online)
  • Monitor job status through webhooks or queries
  • Access delivery confirmations, return receipts, and tracking data automatically

It’s flexible, lightweight, and developer-friendly—built with clean documentation, real code samples, and the support your team actually wants (instead of a 72-page manual with no index).

Need to get HIPAA notices out fast? Want tracking for every customer notice sent as Certified Mail? Done.

Real-World Example: A Law Firm Gets Its Thursdays Back

A midsize legal firm once spent every Thursday printing, assembling, and mailing compliance letters. Tracking Certified Mail was a manual task involving green cards and spreadsheets.

Now, as soon as a case hits a specific milestone in their legal software, a Certified Mail job is sent automatically through the API. It includes:

  • The correct recipient
  • A templated letter
  • Real-time tracking
  • Optional electronic return receipt

No late nights. No manual entry. Just automated compliance—and a team that gets to leave the office on time.

Why It’s About More Than Time-Saving

Sure, automation saves time. But when you’re sending critical, regulated, or time-sensitive mail, it also reduces risk. Manual processes come with built-in error potential.

For industries like:

  • Healthcare (HIPAA timelines and privacy requirements)
  • Legal (court deadlines and delivery proof)
  • Finance (statement timing and compliance notices)
  • HOAs (violation notices, ballot delivery, late fees)

…the LetterStream API provides a secure, trackable, and documented system for sending mail online, with the confidence of a digital audit trail.

No Platform Overhaul Required

This isn’t a rip-and-replace. You don’t have to change your CRM, build a new dashboard, or train your entire team.

In fact, you don’t even have to start big.

Many of our customers begin by automating one simple use case—like sending First-Class statements each month—and scale from there.

Need help from our team? We’ve got you.

Why Our Smartest Customers Use the API

It’s not just about convenience. It’s about building systems that:

  • Reduce human error
  • Create consistency across teams
  • Maintain compliance
  • Free up time for high-impact work

Instead of reacting to last-minute mail needs, your business can operate with proactive, automated workflows that scale with you—without breaking under pressure. That’s the real win.

LetterStream makes print and mail a breeze!

LetterStream offers bulk printing and mailing services, allowing companies to send physical mail online. Whether it’s online Certified MailFirst-Class MailFedEx 2Day, or postcards, we give both small businesses and large corporations that time and freedom back to work on tasks that better serve the company. If you’re interested in creating a free account, you can do so here.

LetterStream small logo

How to Transform the Way You Send Mail With APIs

In today’s digital age, the term “API” is a buzzword that’s gaining traction across various industries. But what exactly is an API, and why is it crucial for businesses, particularly those aiming to streamline their operations when it comes to sending mail online? Well, let us tell you. We believe in leveraging technology to simplify processes, and our print and mail APIs are designed to do just that. Let’s dive into the world of APIs and discover how they can revolutionize your mailing needs.

What is an API?

API stands for Application Programming Interface. In simple terms, an API is a set of rules and protocols that allows different software applications to communicate with each other. Imagine APIs as the middlemen that facilitate interactions between software systems, enabling them to share data and perform tasks seamlessly. APIs are essential for integrating different systems, allowing them to work together efficiently and effectively.

The Power of APIs in Mailing Services

For businesses such as Homeowners Associations (HOAs), law firms, government agencies, healthcare providers and other enterprises, sending mail is a regular but critical task. In the past, this involved manual processes that were time-consuming and prone to errors. However, with the creation and power of APIs, these tasks can now be automated, reducing the workload and increasing accuracy for businesses.

Here’s where we come in. We offer robust print and mail APIs that allow businesses to send mail automatically through our website. Our send mail APIs are designed to integrate smoothly with your existing systems, making the process of sending mail as easy as a few clicks. Whether you need to send invoices, legal documents, annual meeting notices, past-due notices, check mailing APIs or postcards our APIs handle it all with accuracy and speed.

How LetterStream Incorporates APIs

computer with a bunch of envelopes flying out of it and into a mailbox

Our journey with APIs is driven by our commitment to innovation and efficiency. By incorporating APIs, we enable businesses to automate their mailing processes, saving time and reducing costs and who wouldn’t want that? Here’s how it works:

  1. Seamless Integration: Our APIs are designed to integrate effortlessly with your software, whether you use a custom-built solution or popular platforms. This means you can send mail directly from your application without needing to switch between different systems.
  2. Automation at Its Best: Once integrated, our APIs handle the entire mailing process automatically. From printing to postage, everything is managed through our secure and reliable system. You can schedule mailings and track deliveries all through the print-on-demand API.
  3. Customization and Flexibility: We understand that every business has unique needs. Our APIs are highly customizable, allowing you to tailor the process according to your specific requirements. Whether you need to send bulk mailings or individual letters, our API integration offers the flexibility you need.

Benefits of Using APIs

Our print and mail APIs offer significant advantages across various industries. By automating the mailing process, businesses can save time, reduce costs, and enhance efficiency. Here are some key benefits:

Automation: APIs allow for the automatic sending of various mail types, such as First-Class Mail for notices and billing statements, Certified Mail and FedEx 2Day for eviction notices and legal communications, flats for larger mailings and postcards for community information and news. This reduces the need for manual intervention and minimizes the risk of errors.

Security: With built-in security features, our APIs ensure that sensitive information, such as legal documents and patient communications, is handled with the utmost care, complying with relevant regulations and standards.

Efficiency: By streamlining the process of sending mail, businesses can ensure timely communication with their audiences. Whether it’s sending official notices and forms, or communicating important information, API printing and mailing enables quick and efficient mail distribution.

Cost Savings: Automating mailing processes reduces administrative burdens and operational costs. Businesses can allocate resources more effectively, focusing on core business needs rather than manual mailing tasks.

Scalability: Our APIs are designed to handle varying volumes of mail, from individual letters to bulk mailings. This scalability makes it easy for businesses to manage their mailing needs as they grow.

By leveraging our snail mail APIs, businesses can enhance their communication strategies, maintain compliance with regulations, and improve overall operational efficiency. Explore the LetterStream API Partnership to enhance your business operations today!