Get Started with PostGrid’s API in Seconds

Easily send mails, manage templates and verify addresses globally using API



curl \
-u API_KEY: \
-d to[firstName]="Kevin" \
-d to[lastName]="Villena" \
-d to[addressLine1]="145 Mulberry St, Apt PH D, New York, NY 10013" \
-d to[countryCode]="US" \
-d from[companyName]="PostGrid" \
-d from[addressLine1]="90 Canal St, Suite 400, Boston, MA" \
-d from[countryCode]="US" \
-d color=true \
-d express=true \
-d template="template_4hXPyVphgFPynPyHFTJaKo" \
-d mergeVariables[verification_code]=4242



curl \
-u API_KEY: \
-d to[firstName]="Kevin" \
-d to[lastName]="Villena" \
-d to[addressLine1]="145 Mulberry St, Apt PH D, New York, NY 10013" \
-d to[countryCode]="US" \
-d size="6x4" \
-d frontTemplate="template_6a3k5LqumLD7cpdD9VkQUd" \
-d backTemplate="template_oa8Au5h4DqFr1mRDLaKhJz" \
-d mailingClass="standard_class" \
-d mergeVariables[qr_code_url]=""



curl \
-u API_KEY: \
-d to[firstName]="Kevin" \
-d to[lastName]="Villena" \
-d to[addressLine1]="145 Mulberry St, Apt PH D, New York, NY 10013" \
-d to[countryCode]="US" \
-d from[companyName]="PostGrid" \
-d from[addressLine1]="90 Canal St, Suite 400, Boston, MA" \
-d from[countryCode]="US" \
-d bankAccount="bank_k9zDtHjZmBe9ruVC4F8PZN" \
-d amount=4242 \
-d message="Here is the payment for the attached invoice." \
-d letterPDF=""


# List all letters destined for New York that have left their final USPS facility. curl "NY out_for_delivery" \ -u API_KEY: # Retrieve a check and its corresponding bank account curl[]="bankAccount" \ -u API_KEY:


# Automatically parse and correct a freeform US or Canadian address curl \ -u API_KEY: \ -d address="14-20 bay st, floor 11, toronto, on, canada" # Use our international API to verify addresses around the world curl \ -u API_KEY: \ -d address[line1]="33 Nine Elms Lane" \ -d address[city]="London" \ -d address[postalOrZip]="SW11 7US" \ -d address[country]="United Kingdom"


# List US & Canada previews for partial address input curl \ -u API_KEY: # List addresses from around the world, sorted by distance to user IP curl \ -u API_KEY:
Read our API Docs

Seamless Solution for Your Direct Mail Marketing

Strengthen your B2B relationships with an easy-to-use all-in-one solution –  PostGrid. With us, you can send personalized direct mail for more customer engagement, automate the entire direct mailing process using direct mail automation software to save time and resources, track the ongoing campaigns and get their analytical reports to improve your future campaigns, and integrate your enterprise system or website to fetch tons of data within seconds.

Let’s find out how it actually helps you improve your relationships with your clients or prospects.

customer relationship

How It Helps You Improve Your Relationships With Your Customers

Instead of opting only for online solutions, when you send to your potential or existing customers and clients, personalized tangible direct mail creates a higher impact and makes the receiver feel valued. Plus, the open rate of direct mail is way higher than email, and it helps you grab the opportunity instantly. In addition, direct mails have a response rate of 5.1% better than any other digital marketing strategy as – even today – people love to receive postal mail.

So, grab this opportunity, and start sending direct mail to your customers without investing much time with the help of PostGrid and improve your return. We’ll discuss the further benefits of direct mail API and postal API in detail.

What Is a Direct Mail API

A direct mail API lets you automate your direct mail – just like email – with the help of direct mail software like PostGrid. All you have to do is integrate it with your CRM, eCommerce, or marketing platform. Once done, the system sends direct mail based on your prospects’ or customers’ actions.

With the help of direct mail software like PostGrid, you wouldn’t need to worry about running out of ink, missing out on sending an emergency direct mail, folding the letters, putting them in the envelopes, running back and forth to the post offices, and other tedious tasks.

There are many more benefits of API, let’s understand them in detail.

implement zip code direct mail api

Benefits of Direct Mail API

Fully Automated

With an automated system, like PostGrid, you can trigger each of your direct mail, whether it’s a welcome mail, thank you mail, confirmation mail, invoice, monthly report, or anything. Plus, you can also personalize them in terms of design, and message, and send targeted mail to the right user. Once set, you can forget about it and let our system do the job for you, each time a person enters your campaign.


The safety of our client’s data and sensitive information is our number one priority at PostGrid. Hence, we make sure that every transaction or other data shared remains confidential. Besides that, PostGrids has a highly compliant and secure print and mail processing partnership ensuring you are able to boldly send any direct mail containing any kind of data whether sensitive or simple marketing message with trust.

Strengthen Customer Relationships

Without you getting involved in any tedious tasks, your customers will continue to receive direct mail with the relevant offers and discounts that you have to offer, the birthday or anniversary mail, other thank you, sorry, query, or follow-up mail. Hence, these letters will help you maintain good relationships with your customers and save you time and resources.

Enhance Customer Engagement

It keeps them engaged with your company and products, and eventually, your brand remains at the top of their minds. Send highly personalized and targeted mail with relevant offers pertaining to the right users. The entire process will run automatically and you won’t need to invest your time in any of the steps.

Test and Launch

PostGrid allows you to test your campaigns before launching them in front of a large audience, get the analytical report, and find out whether it will work out or not. This practice will save you tons of time, money, and resources that you will put into this campaign.

Show Professionalism

Manual tasks, along with being tedious in nature, open the gate to loads of errors. It may stand in the way of your company’s good reputation. Using an automated tool, like PostGrid, you can get rid of all the tiny errors, and unnecessary delays, and trigger on-time delivery, furthermore, showing off your company’s professionalism. And eventually, with regular direct mail, increase your brand awareness, and engagement, and get a higher customer retention rate.

Analytical Reports

By integrating your CRM with PostGrid, you can track all of your launched campaigns by getting regular reports or by checking them from your dashboard. Beginning from tracking your direct mail processing, printing, shipping, and delivery to getting the final analytical reports on the performance of your campaigns, you can get every tiny detail from your dashboard. This way, you can significantly improve your customers’ engagement, retention, and repeat business, and garner high returns.

Full Control

Without relying on your different teams and departments, designers, and writers, printing and postal services, you can manage everything yourself. Easy implementation with detailed API docs and dev support, seamlessly integrate with your current CRM without having to change your existing workflow through PostGrid’s Direct Mail API, and have added capabilities to send personalized letters, postcards, and cheques.


If you’re looking for the long-term benefits and really want to know how an automated system can be budget-friendly, then calculate the cost price of your launched campaigns. The time, money, efforts, physical and human resources you invested without being able to track any of them will turn out to be more expensive than investing in an all-in-one solution.

Multiple Industries

With PostGrid Direct Mail API, all industries like real estate, financial, banks, nonprofits, law firms, b2b, healthcare, education, fintech, and many other sectors can benefit.

How Does Direct Mail API Work

personalized direct mail services

The direct mail API works in the following ways

  • Integrate your CRM, eCommerce, or enterprise system with the direct mail software.
  • Fetch all the data – names, addresses, other contact information – from your system within seconds.
  • Create customized direct mails such as letters, postcards, and checks using our letter API, postcard API, and checks API.
  • Set the trigger-based direct mail campaigns in your CRM and automate the entire process with direct mail API.

This process can help you send regular direct mail to your prospects and customers without any interruption and eventually increase your brand awareness, strengthen your relationships with your clients, and revamp your returns.

Features of PostGrid's Direct Mail API

Integrate and launch

Launching direct mail can be daunting when you have to manually do all the tasks. Plus, tedious tasks can also open the door to countless errors that can, sometimes, create massive problems for your brand. Hence, data automation is almost always the best solution. With PostGrid, you can incorporate your CRM, eCommerce, or enterprise system and fetch your customers’ details within seconds. It not only saves you time but also helps you maintain your professionalism, which later on turns out to be quite useful for the company’s reputation.

Scale any time

Whether you need to send one or one thousand direct mail, on PostGrid, we allow you to launch a direct marketing campaign of any number of mailers. Plus, you can also scale your campaigns at any time without worrying about any of the processes involved. From printing to delivering your exact mailpieces to the right addresses is totally our responsibility.

Send Emergency Letters

Oftentimes, businesses face the need to send emergency direct mail, viz., invoices, query letters, or any other type of direct mail. With an automation tool, like PostGrid, in place, you can send these emergency mailpieces, despite the number, at any time.

Customize for Better Engagement

Launching personalized marketing campaigns is no longer a choice; it’s a necessity. If you want to outdo your counterparts, sending customized direct mail can go a long way. This approach can help your customers feel valued and trust your brand even more. So, choosing a direct mail API software that makes personalization simple and easy for you is only wise. With PostGrid, you can customize each of your direct mail – even if it’s a general invoice – by just setting up the system accordingly from your dashboard. It eventually helps you receive more customer engagement and better responses in return.

Easy to use

With PostGrid, you can launch your personalized direct mail marketing campaigns by controlling everything from your dashboard. To get started, create and save the design of your mailpiece, viz., letters, brochures, catalogs, postcards, or any other mailer. Fetch your customers’ list from your system by integration, or get a highly targeted list. Once it’s done, have your uploaded or fetched customers’ details verified with our address verification software. And finally, launch your campaign. (The detailed process is discussed in the later section.

Track and Analyze

When you launch your direct mail promotions using PostGrid, we send you regular notifications on the location of your mailpieces. And once they’ve been delivered to the targeted recipients.

FAQs About PostGrid

How Does PostGrid Works For Printing and Mailing Letters?

PostGrid is a Print and Mail API for managing the printing and mailing of all types of direct mail. Its usage is relatively easy. All you have to do is:

  • Select a template and fill in the details of your message, upload your own template, or create a design from scratch.
  • Upload the CSV file of your contact list, or integrate PostGrid with your system and fetch all the data within seconds.
  • Get all the addresses verified with our – free of cost – address verification software for reducing the bounce rate, misspending, and lost opportunities.
  • Track all of your letters campaign from printing, processing, and shipping to final delivery.
  • Get analytical details of all of your campaigns to improve your future campaigns and get better returns.
  • Automate every process and launch future campaigns with a single click.
  • Control everything from a single dashboard.
  • Get better deals at per-piece printing.

Are PostGrid Direct Mail API Processes HIPAA compliant?

Our services and facilities are HIPAA compliant for customers who need them. To ensure your documents comply with HIPAA, please contact sales to get a BAA signed.

What Product Specifications for Direct Mail Letters are Available at Postgrid?

Our commercial printer network uses a few pre-approved papers. Every paper source specification must fall within a small range to ensure uniform quality and consistency. The following specifications and ranges are provided:

US & International size guidelines are:

  • 6×4
  • 9×6
  • 11×6

Other Specifications:

  • Basis Weight: 60# text
  • GSM: 89 – 90
  • 10% PCW Product
  • FSC Certified

You can find product specifications related to the specifications of our API to send direct mails here.

How Much Does PostGrid's Direct Mail API Cost?

Please get in touch with us to learn about your needs and offer the best solutions and pricing.

How Much Can I Save if I Decide to Use Postgrid?

With PostGrid, you save money by getting the best deals on per-piece printing due to our vast sending volume. Using our free address verification software, you can save the amount you’ll spend on letters addressed to the wrong audience or sent multiple times to the same person. Besides that, you can save time, effort, and resources that would otherwise be spent on doing tedious tasks manually.

What is PostGrid’s Day-to-Day Cut Off Times for Letters?

We accept submissions until 10 am PST each day; anything received after that time will be processed on the next production run. If your send date overlaps, a daily cut-off time with the cancellation window or scheduling feature will be slotted into the next production day. This includes all public holidays and normal business days.

Can I Send Letters Containing Sensitive Information?

All our partners are PIPEDA/HIPAA compliant, and hence you can send any letter containing any sensitive information through our API to send direct mail. You can easily send billing statements, checks, invoices, financial statements, compliance notices, or any other type of mail to us.

How Long Would I Need to Wait for the Delivery of My Letters?

PostGrid offers the industry-best SLA ranging from the same day to 2 days for the handover of your collaterals to local postal service providers for delivery.

How Does the Payment System Work at Postgrid Direct Mail API?

You can use any method of payment that you’re comfortable with, for example: receiving invoices, credit lines, PayPal, credit cards, bank transfers, etc.

Does PostGrid Offer eReceipts of Return?

Definitely, you will get all the information related to your print & mail by integrating our direct mail API! The USPS offers a Certified Mail add-on that allows the sender to receive an Electronic Return Receipt. This receipt allows you to download a digital copy of the recipient’s signature. The “extra_service” parameter of creating a letter gives you the option of creating an Electronic Return Receipt rather than a certified return receipt.

On the USPS website, the certified tracking number will enable you to access the return receipt. The following steps will assist you in receiving the signature PDF via email:

  • You can visit
  • Under the section- Track a Package by entering the Certified tracking number
  • Fill out the required fields under “Return Receipt Email”

What Additional Mail Services Do You Offer?

Our Print & Mail product offers the following additional services:


  • Certified Mail – Track domestic mail using the US Postal Service
  • Registered Mail – Track international mail using US Postal Service for Registered Mail
  • Electronic Return Receipt – This indicates that the package has been delivered


  • Web-to-print industry: Add quirkiness and other types of graphics with innovative printing techniques
  • Featured postcards: Know the market trends before launching postcard printing
  • Automated postcard mailing: Automate your project and personalized postcards with PostGrid

Also, our other services include the invoice, check, and envelope printing. All you have to do is integrate our direct mail API with your CRMS and other system solutions. You can find a detailed list of our offerings and their associated prices by visiting our pricing page.

What is The Most Accurate Way to Know If My Letter Will Require Additional Postage?

If you are wondering how I send a letter with direct mail API- There is a flat fee of $2.00 for each additional page over 6 pages single-sided and $12.00 for letters over 12 pages double-sided. For more information, please visit our pricing page.

Integrates with Your Favorite Tech Stack & Tools

Easily Improve your workflow and automate print & mail through seamless integration capabilities.

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PostGrid Marketo
Post Grid Eloqua
PostGrid Hubspot
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Ready to Get Started?

Start transforming and automating your offline communications with PostGrid