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What Is Intelligent Mail Barcode (IMb) and How Does It Work?
By Lee Garvey
If you’ve looked closely at a piece of business mail recently, you’ve likely noticed a row of tall and short bars printed near the address area. That’s the Intelligent Mail Barcode, and it carries significantly more information than it appears to. For businesses that send mail at any volume, understanding how IMb works — and what it makes possible — changes how you think about mail tracking, delivery timing, and campaign coordination.
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What Is the Intelligent Mail Barcode?
The Intelligent Mail Barcode, commonly referred to as IMb, is a 65-bar barcode developed by the USPS to track and sort mail pieces throughout the postal network. It replaced two older barcode systems — the POSTNET barcode and the PLANET Code — combining their functions into a single, more capable standard.
Each IMb encodes up to 31 digits of data, including:
- A barcode identifier
- A service type code indicating the mail class and special services
- A mailer identifier linking the piece to the sending organization
- A serial number unique to each individual mailpiece
- The destination ZIP code
That last point is worth emphasizing: every single mailpiece gets its own unique serial number. This is what makes individual piece tracking possible, as opposed to the older system where tracking was limited to bulk batches.
The USPS provides detailed technical specifications for the Intelligent Mail Barcode for mailers and developers who need to work with the standard directly.
How IMb Tracking Works
As a mailpiece moves through the postal system, the IMb is scanned at multiple points along the way. Each scan creates a record that includes the location, the time, and the status of the piece. Those records are aggregated into the USPS tracking database and made available to senders in near real time.
The journey of a typical tracked mailpiece generates scans at several stages:
- Acceptance — when the piece enters the postal system at a processing facility
- In transit — as it moves between sorting facilities en route to its destination
- Out for delivery — when it’s loaded onto a carrier’s route
- Delivered — when it reaches the recipient’s address
For businesses using Click2Mail, this scan data is automatically captured and returned through the platform. You don’t need to check the USPS website manually — the tracking information comes back to you as part of your mailing record.
IMb vs Standard Package Tracking
A common point of confusion is the difference between IMb tracking on letter mail and the tracking most people are familiar with from package shipping. They work on the same general principle but with some important differences.
Package tracking on Priority Mail and Priority Mail Express is highly granular, with frequent scans and near-guaranteed delivery confirmation at the piece level. IMb tracking on standard First Class Mail and marketing mail is less granular — not every piece gets scanned at every stage, and delivery confirmation is not always captured for every mailpiece.
That said, IMb tracking on First Class Mail still provides meaningful data, particularly at the campaign level. When you’re mailing thousands of pieces, the aggregate scan data tells you when your campaign is reaching mailboxes — which is exactly what you need to coordinate follow-up outreach across channels.
Why IMb Matters for Business Mailers
Delivery Timing and Campaign Coordination
Knowing when your mail is arriving lets you synchronize other marketing and sales activities around it. As Click2Mail CEO Lee Garvey explains: “You want them to get a phone call at the same time they get mail in the mailbox, and emails should arrive as the mail piece gets in the mailbox. You can’t do that normally — but with Click2Mail, we give you the data coming back from the postal service so you can do it automatically.”
This kind of multi-channel timing is one of the most effective ways to increase response rates, and it’s only possible with reliable delivery data.
Operational Planning
For businesses sending invoices, statements, or time-sensitive notices, knowing when mail is arriving at recipients’ local post offices allows customer service teams to anticipate incoming calls and questions. Carly Brown, Click2Mail’s customer support manager, describes the operational value: “If you know that all of your direct marketing pieces have arrived at the recipients’ post office, you can anticipate getting a bunch of phone calls the next day — it gives you extra planning abilities.”
Compliance Documentation
For regulated industries, IMb scan data contributes to the audit trail that proves a notice was mailed and when. Combined with Certified Mail tracking and a Return Receipt, it creates a complete delivery record that holds up in legal and regulatory proceedings.
Postage Discounts
Using IMb-compliant barcodes qualifies mailers for automation postage discounts from the USPS. Pieces that meet USPS automation compatibility standards — correct barcode placement, address formatting, and clear zone compliance — receive lower postage rates than non-automated mail. Click2Mail applies CASS-certified address processing and IMb encoding automatically, so every mailing qualifies for available discounts without any additional steps from the sender.
IMb and Address Quality
The IMb doesn’t just track mail — it’s also part of the USPS address correction and forwarding system. Service type codes embedded in the barcode tell postal carriers what to do with a piece if the recipient has moved or the address is undeliverable. Options include forwarding the piece, returning it to the sender, or notifying the sender of the new address electronically.
This is one reason address quality matters so much before a mailing goes out. An accurate address means the IMb works as intended. A bad address means the piece may be returned, forwarded to an unknown location, or simply discarded — with the tracking data reflecting that outcome and nothing more.
Click2Mail applies automatic NCOA (National Change of Address) processing to all mailings, cross-referencing recipient addresses against the USPS change of address database before pieces go to print. This catches outdated addresses before they become wasted postage.
How to Get IMb Tracking on Your Mailings
For businesses sending mail through Click2Mail, IMb tracking is included automatically on every mailpiece at no additional cost. There’s no separate enrollment, no barcode to generate manually, and no additional setup required. The barcode is applied during production, the scan data is captured as the piece moves through the postal network, and the delivery information feeds back into your mailing records automatically.
Physical mail has always had a delivery problem — not in actually getting there, but in knowing when it got there. The Intelligent Mail Barcode solves that problem, turning every piece of outgoing mail into a trackable, data-generating asset. Visit Click2Mail.com to start sending tracked mail without any additional setup or cost.
About Lee
Lee Garvey is the founder of Click2Mail, a pioneering platform in cloud-based direct mail automation since 2003. Under his leadership, Click2Mail has become a trusted USPS partner, helping thousands of businesses streamline their mailing processes and effectively bridge the gap between digital and physical marketing.
From your desk — in minutes
Launch 500 postcards / flyers / letters in ~5 minutes. We print, address, and mail for you.
Upload your design and mailing list, pay, done.
No post office run. No subscriptions.
Next-business-day mailing for most products.
Create your free account
No minimums. Use any email to get started.
Why List Quality Makes or Breaks Your Campaign
When discussing the factors that impact direct mail costs and effectiveness, Click2Mail founder and CEO Lee Garvey doesn’t mince words: “I think the biggest variable is the list.”
Carly Brown, customer support manager at Click2Mail, agrees: “You really got to spend money on a good list. If you send that mailpiece to people who don’t want your product or service, you’re just setting money on fire.”
This insight aligns with what direct marketing experts have known for decades. The success of your campaign depends on three key factors:
- 40% – The quality of your mailing list
- 40% – The strength of your offer
- 20% – The creative design and copy
In other words, where your mail goes matters twice as much as all that design work and writing effort you put into it. But what exactly makes a mailing list “good,” and how can you ensure yours meets the standard?
Building a Quality Mailing List: The Fundamentals
When building your mailing list, you should adhere to four fundamental best practices.
1. Start with Clean Data
List hygiene isn’t just a best practice—it’s essential for preventing wasted resources. Signs of poor list quality include:
- Undeliverable addresses
- Duplicate entries
- Outdated customer information
- Missing apartment numbers or suite information
“If your list has more than 10% nonstandard addresses, we’ll warn you,” notes Carly. “Maybe you did something wrong, and you exported the list wrong, might have a bunch of missing apartment numbers.”
This seemingly small oversight can have major consequences for your bottom line.
“The idea of apartment numbers is really huge,” Lee says. “If you’ve got a list of apartment dwellers and don’t have numbers, you can mail out 10,000 pieces of mail that won’t get delivered, and if you send it out bulk mail at standard marketing mail rate, you won’t know because they just get thrown away.”
Tip: Run regular NCOA (National Change of Address) updates on your mailing lists at least quarterly to catch address changes and reduce undeliverable mail.
2. Understand the Different Types of Lists
Not all mailing lists are created equal. Depending on your goals, you might consider:
- House Lists: These consist of your existing customers and prospects who have already shown interest in your business. They typically produce the highest response rates because you’ve already established a relationship with these individuals.
- Prospect Lists: These are lists of potential customers acquired from third-party providers. While response rates tend to be lower than house lists, they’re essential for growing your customer base.
- Response Lists: These contain individuals who have responded to similar offers or have purchased similar products, making them more likely to respond to your offer than completely cold prospects.
- Compiled Lists: These are built from various public and private sources based on demographic characteristics. They’re typically less expensive but may yield lower response rates than response lists.
Tip: Start with small test mailings to different list types before committing to a large campaign. Track response rates carefully to determine which list provides the best ROI for your specific offer.
3. Get Granular with Targeting
The power of direct mail lies in its ability to reach highly specific audiences. As Lee points out, the specificity of your list affects both its cost and effectiveness.
“If you’re looking for a list of women in Fredericksburg, you can get it for cheap,” he says. “If you want to limit it to people who own 3-story houses with porches, that will cost you more.”
But this increased cost often translates to better results. The more precisely you can target your ideal customer, the higher your response rate is likely to be.
Modern list providers offer increasingly sophisticated targeting options:
- Demographics: Age, gender, income, education, family status
- Geographic: ZIP codes, neighborhoods, radius targeting
- Psychographics: Interests, values, attitudes, lifestyles
- Behavioral: Past purchases, channel preferences, brand loyalty
“With technology we have access to, you can get very granular,” Lee notes.
For instance:
- An upscale furniture retailer might prioritize high-income households
- A family daycare center might focus on addresses with children under 5
- A senior living community would target households with residents over 65
Tip: Instead of trying to reach everyone, identify your 2-3 most profitable customer segments and create highly targeted mailings for each. A smaller, more targeted campaign often outperforms a larger, generic one.
Industry-Specific List Strategies: Examples
Different industries leverage different data points to refine their targeting. Here’s a few examples.
Real Estate
Real estate professionals often use sophisticated list targeting based on property characteristics and ownership status.
“Some will get a mailing list and know how much equity you have in the house, how many bedrooms it has, if you have a fireplace or a pool – things like that,” Carly says. “Then they’ll send you a mailer that says something like, ‘hey I’m great at selling houses with pools.”
B2B Marketing
Business-to-business marketers can also benefit from specialized list criteria.
“There’s a lot of money going into solar right now,” Carly says. “They reach out to property owners who have a large building with a big roof. You can get a list of property owners that list the square footage of their building.”
This level of targeting ensures that businesses only receive offers relevant to their specific situation, dramatically improving response rates.
Financial Services
Financial institutions often segment their lists based on life stages, wealth indicators, and specific financial behaviors.
For mortgage lenders, this might mean targeting homeowners with high interest rates who could benefit from refinancing. For investment advisors, it could involve identifying individuals approaching retirement age with certain income levels.
The key is matching financial products to the specific needs and circumstances of the recipient—something that requires highly precise list selection.
Ready to Improve Your Direct Mail Results? We Can Help You Save Time and Money
Investing in list quality isn’t just about avoiding wasted mail—it’s about dramatically improving your campaign ROI. With the right list strategy, your direct mail can reach exactly the people most likely to respond to your offer.
Click2Mail makes it easy to implement these best practices with built-in address validation, easy list management tools, and helpful support from direct mail experts. Whether you’re using your own customer list or need help acquiring a targeted prospect list, we can help you ensure your mail reaches the right mailboxes.
Start your next campaign with confidence. Visit Click2Mail.com today to access our simple list management tools and send direct mail that gets results—not recycled.
About Lee
Lee Garvey is the founder of Click2Mail, a pioneering platform in cloud-based direct mail automation since 2003. Under his leadership, Click2Mail has become a trusted USPS partner, helping thousands of businesses streamline their mailing processes and effectively bridge the gap between digital and physical marketing.