What Is a Lettershop? How Mail Houses Handle Direct Mail Fulfillment

The phrase “lettershop” doesn’t show up in many business owners’ vocabulary until they try to produce a direct mail campaign on their own for the first time. That’s when they discover that printing the piece is step one of a multi-step process, and the remaining steps — addressing, sorting, bundling, delivering to USPS — require equipment, permits, and USPS knowledge that most businesses don’t have.

A lettershop handles those steps. At Cornerstone Services in New Paltz, we are both a printer and a lettershop — we produce the printed pieces and handle the mailing preparation, which means a client’s campaign goes from concept to USPS delivery without the piece leaving our facility.

Here’s exactly what a lettershop does.

The Steps a Lettershop Handles

Address Processing

Before any addressing happens, the mailing list needs to be processed through USPS database systems:

CASS Certification — CASS (Coding Accuracy Support System) is a USPS certification process that standardizes and verifies postal addresses. CASS software checks each address in your list against the USPS address database, corrects formatting errors, adds ZIP+4 codes and delivery point codes, and flags addresses that don’t match a valid USPS record. CASS certification is required for presort mail and significantly reduces undeliverable pieces.

NCOA Processing — NCOA (National Change of Address) matches your list against the USPS change-of-address database and updates addresses for anyone who has filed a change-of-address in the past 18 months. USPS requires NCOA processing within 95 days of the mail date for all presort mail.

After CASS and NCOA, the lettershop applies IMb (Intelligent Mail Barcode) barcodes to each piece. IMb barcodes are the machine-readable code that USPS automated processing equipment uses to route and track mail. Applying IMb barcodes is a requirement for presort discounts.

Inkjet Addressing

Inkjet addressing applies the recipient’s name, address, and IMb barcode directly to the mail piece using a high-speed inkjet printer. This replaces address labels, which can peel in USPS processing equipment and are increasingly uncommon in professional direct mail.

The addressing can be applied to:

• The address panel of a self-mailer (postcard or folded brochure)
• A clear or white address area on the piece
• A window envelope where the address on the letter shows through
• A separately-addressed label (less common, used for certain formats)

Inserting and Stuffing

For letter-package mailings (envelope + letter + reply card + return envelope), a lettershop uses high-speed inserting equipment to:

1. Fold the letter to the appropriate size
2. Insert all components (letter, reply card, any enclosures) into the outer envelope
3. Seal the outer envelope
4. Apply the address to the outer envelope

High-speed inserting equipment runs 15,000–25,000 pieces per hour. Hand-stuffing the same quantity would take a full team days. For any campaign over a few hundred pieces, machine inserting is significantly faster and more cost-efficient.

Presort Sorting

Presort mail must be sorted in a specific USPS sequence before induction. The USPS offers discounts for mail sorted more precisely:

• 5-digit sort: All pieces for a specific ZIP code grouped together
• Carrier route sort: More precise — pieces sorted to the specific carrier route within each ZIP code
• Automation sort: Highest precision, requires barcode, earns the deepest discounts

Lettershop presort software applies USPS PAVEACS and FAST sequencing to generate sort documentation. The sorted pieces are bundled, strapped, and placed in USPS trays with proper tray labels.

USPS Induction

The final step: delivering the prepared mailing to the USPS. For Marketing Mail, this is done at a USPS Business Mail Entry Unit (BMEU), where USPS acceptance staff verify:

• Documentation (postage statement, tray labels)
• Piece count
• Presort accuracy
• Barcode and format compliance

The lettershop delivers the mailing with all required documentation, pays postage from the client’s permit account or the lettershop’s permit, and provides a mailing receipt.

When a Lettershop Saves You Money

The cost of lettershop services ($0.025–$0.15 per piece depending on services used) is offset by:

Postage savings from presort. Marketing Mail automation rates (what presort earns) versus First-Class single-piece rates represent a postage savings of $0.30–$0.45 per piece. On a 5,000-piece mailing, the presort discount saves $1,500–$2,250 in postage. Lettershop fees are typically $150–$400 for the same 5,000-piece job. The math is straightforward.

Reduced undeliverable rate. CASS and NCOA processing typically reduces undeliverable mail by 3–8%. On a 10,000-piece mailing at $0.70 per piece all-in, a 5% reduction in waste saves $350.

Eliminated permit costs. A USPS presort permit costs $240/year plus permit fees per mailing. Using the lettershop’s permit eliminates this overhead entirely for occasional or low-volume mailers.

Your time. Bundling, tray preparation, and USPS delivery for a 5,000-piece mailing takes 4–8 hours if done manually. At any reasonable valuation of your time, the lettershop fee is the better option.

Lettershop Services by Campaign Type

Different direct mail formats require different lettershop services. Here’s what applies to each:

Postcard campaigns (targeted mail):

• CASS certification and NCOA processing on the mailing list
• Inkjet addressing with IMb barcode on the address side
• Presort to maximum qualifying level
• Tray preparation and USPS induction
• No inserting or folding required — postcards are single-piece flat mail

This is the simplest lettershop workflow. A 5,000-piece postcard mailing typically processes in one business day from receipt of the printed pieces and approved list.

Letter package campaigns (envelope + letter + inserts):

• CASS and NCOA on the mailing list
• Letter printing (often with variable data — personalized name, offer amount, account number)
• Folding the letter to fit the outer envelope
• Inserting all components: letter, reply card, return envelope, any additional enclosures
• Sealing the outer envelope
• Inkjet addressing on the outer envelope (or window envelope where the letter address shows through)
• Presort and USPS induction

Letter packages are the most labor-intensive format. Multi-component packages (letter + 3 inserts + return envelope) require careful machine setup to ensure every envelope receives every component in the correct order. At Cornerstone, we verify insert completeness with piece counting and spot-checking throughout the run.

Self-mailer campaigns (folded brochures, newsletters):

• CASS and NCOA processing
• Folding (if not already folded by the printer)
• Tabbing — applying wafer seal tabs to open edges per USPS requirements
• Inkjet addressing on the address panel
• Presort and USPS induction

Self-mailers are increasingly popular because they eliminate the envelope cost and insertion step. The tradeoff: tabbing adds a production step, and the design must accommodate the address panel and USPS clear zones within the folded layout.

EDDM campaigns:

• No list processing needed (EDDM has no individual addresses)
• Bundling in stacks of 50–100 pieces
• Facing slip preparation (USPS PS Form 3587 for each bundle)
• Drop at the serving USPS delivery unit
• Postage payment at the counter ($0.247/piece)

EDDM is the simplest lettershop workflow because there is no addressing, no presort, and no list processing. The lettershop’s value is in the bundling, facing slip preparation, and knowledge of which USPS facility serves which carrier routes.

Print + Mail Under One Roof: Why It Matters

The most significant advantage of a combined print-and-mail facility like Cornerstone is elimination of the handoff gap. When printing happens at one vendor and mailing at another, the process involves:

1. Printing vendor produces the pieces
2. Pieces are packaged and shipped to the mail house
3. Mail house receives, unpacks, and inspects the pieces
4. Any print quality issues are discovered after the pieces have shipped — reprinting requires going back to the printer, waiting for new pieces, and reshipping

At Cornerstone, pieces move directly from the press to the mail department — no shipping, no receiving delay, no inspection of work done by another vendor. If a print issue is discovered during mailing preparation, the press is in the same building and can re-run the affected pieces immediately.

For campaigns with tight deadlines — event announcements, seasonal promotions, time-limited offers — this single-facility workflow can save 2–3 business days compared to a split-vendor approach.

How to Get Started With a Lettershop

If you’ve never used a lettershop before, here’s what to have ready when you call:

Your mailing list — in a spreadsheet (Excel, CSV) with columns for name, address, city, state, and ZIP code. Don’t worry about formatting — we standardize and clean the list through CASS and NCOA processing as part of every job.

Your printed pieces — or the print-ready files if you want us to handle printing as well. If you’re bringing pieces printed elsewhere, make sure the address side is receptive to inkjet addressing (not UV coated). If you’re not sure, send us a sample before the full print run and we’ll test it.

Your budget and timeline — knowing your total budget (including postage) and the date you need the mail to arrive helps us recommend the right mail class, presort level, and production schedule.

Your campaign goals — what you’re trying to accomplish with this mailing. A customer retention postcard has different list, design, and frequency considerations than a new customer acquisition campaign or a nonprofit fundraising appeal. The more context we have, the better recommendation we can make.

At Cornerstone, initial campaign consultations are free and typically take 15–20 minutes. We’ll review your list, recommend a format and mail class, provide a complete quote (printing, addressing, presort, postage, and USPS drop), and confirm the production timeline — usually within the same business day.

To get a quote for mailing services — addressing, presort, USPS drop, or all three — call (845) 255-5722 or request a quote.