# Guides USPS mailing and shipping in 25 guides, each answering the questions people ask about one subject and linking the product pages that belong to it. ## Mailing ### [USPS mail classes](https://postalref.com/guides/mail-classes.md) USPS mail classes group mail by content, such as First-Class Mail for correspondence and USPS Marketing Mail for circulars and catalogs. Within a class, postage depends on weight, on distance for zoned products, and on the preparation and volume that commercial prices require. Each class has service standards, USPS's delivery goals, usually counted in days. - [Periodicals](https://postalref.com/products/periodicals.md) - [Periodicals Accuracy, Grading, and Evaluation (PAGE) Program](https://postalref.com/products/periodicals-accuracy-grading-and-evaluation-page-program.md) - [Election Mail and Political Mail](https://postalref.com/products/election-mail-and-political-mail.md) ### [USPS extra services](https://postalref.com/guides/extra-services.md) USPS extra services add proof or protection to mail for a fee: Certified Mail proves delivery, signature services control who signs, and insurance covers loss. Return Receipt sends the sender the signature, Registered Mail tracks a piece by receipts, and other services collect payment or hold a package for pickup. - [Certificate of Mailing](https://postalref.com/products/certificate-of-mailing.md) ### [Intelligent Mail barcodes on letters, flats and trays](https://postalref.com/guides/intelligent-mail.md) The Intelligent Mail barcode on a letter or flat encodes up to 31 digits in 65 bars: a 20-digit tracking code and a ZIP Code. Trays, tubs and sacks carry an Intelligent Mail tray label with a 24-digit barcode, and pallets a 21-character Intelligent Mail container barcode. All three carry the mailer's Mailer ID. - [Intelligent Mail Barcode](https://postalref.com/products/intelligent-mail-barcode.md) - [Intelligent Mail Container Barcode](https://postalref.com/products/intelligent-mail-container-barcode.md) - [Intelligent Mail Tray Label](https://postalref.com/products/intelligent-mail-tray-label.md) - [Service Type Identifiers (STIDs)](https://postalref.com/products/stids.md) ### [Presort: bundles, trays, pallets and labeling lists](https://postalref.com/guides/presort.md) To earn presort prices, a mailer sorts a bulk mailing by ZIP Code into bundles, trays, sacks and pallets, finest level first. In general, the finer the sort, the lower the price. USPS labeling lists give the destination each container is labeled to. - [Labeling Lists](https://postalref.com/products/labeling-lists.md) ### [Mailpiece design: size, shape and machinability](https://postalref.com/guides/mailpiece-design.md) A mailpiece's length, height, thickness and weight make it a letter, a flat or a parcel, USPS's mail processing categories. A letter is at most 11-1/2 by 6-1/8 inches and 1/4 inch thick, a flat 15 by 12 inches and 3/4 inch thick. A piece that machines can't sort is nonmachinable and may pay a surcharge. - [Alternative Designs](https://postalref.com/products/alternative-designs.md) - [Polywrap and Polywrap Manufacturers](https://postalref.com/products/polywrap-and-polywrap-manufacturers.md) ### [eDoc: Mail.dat, Mail.XML and postage statements](https://postalref.com/guides/edoc.md) Mailers describe a mailing to USPS with electronic documentation, or eDoc, an electronic postage statement they send to PostalOne!, the USPS system that records mailing transactions. Small mailers make it in one of two USPS web tools, Postal Wizard or the IMsb Tool. Mailers with presort software send it as Mail.dat files or Mail.XML messages. - [Electronic Documentation (eDoc)](https://postalref.com/products/edoc.md) - [USPS Technical Specifications for Mail.dat and Mail.xml](https://postalref.com/products/usps-technical-specifications-for-mail-dat-and-mail-xml.md) - [Current Web Service Description Languages (WSDLs)](https://postalref.com/products/current-web-service-description-languages-wsdls.md) - [Test Environment for Mailers](https://postalref.com/products/test-environment-for-mailers.md) ### [Full-Service, Seamless Acceptance and eInduction](https://postalref.com/guides/full-service.md) Full-Service Intelligent Mail is the USPS automation option that requires unique barcodes on every piece, tray and container and electronic documentation of the mailing. USPS checks that documentation after the postage statement is finalized and reports errors in the Mailer Scorecard. With eInduction and Seamless Acceptance, it is one of three USPS initiatives that streamline acceptance, induction and verification. - [Full-Service Assessments](https://postalref.com/products/full-service-assessments.md) - [Full-Service Certification](https://postalref.com/products/full-service-certification.md) - [Mailer Scorecard](https://postalref.com/products/mailer-scorecard.md) - [Seamless Acceptance](https://postalref.com/products/seamless-acceptance.md) - [eInduction](https://postalref.com/products/einduction.md) ### [Reply mail: Business Reply Mail and Share Mail](https://postalref.com/guides/reply-mail.md) A business pays the postage on its customers' replies with Business Reply Mail: USPS collects postage plus a per-piece fee only on the pieces customers actually send back. Share Mail lets customers mail a business's letters and postcards on to other people, at the business's cost. Permit Reply Mail and Metered Reply Mail prepay the reply instead. - [Business Reply Mail](https://postalref.com/products/business-reply-mail.md) - [Share Mail](https://postalref.com/products/share-mail.md) ### [Saturation mail: EDDM, Marriage Mail and walk sequence](https://postalref.com/guides/saturation-mail.md) Businesses reach most or all of the addresses on a carrier route with saturation mail, sorted in walk sequence, the order the carrier delivers. Every Door Direct Mail sends it addressed to Postal Customer, and Marriage Mail combines several advertisers in one piece. Walk-sequence address lists come from Computerized Delivery Sequence, for mailers whose own lists qualify through Electronic Address Sequencing. - [Every Door Direct Mail](https://postalref.com/products/every-door-direct-mail.md) - [Marriage Mail](https://postalref.com/products/marriage-mail.md) - [Computerized Delivery Sequence](https://postalref.com/products/cds.md) - [Electronic Address Sequencing](https://postalref.com/products/eas.md) ## Shipping ### [Package labels and tracking numbers (IMpb)](https://postalref.com/guides/package-labels.md) A domestic USPS tracking number names the package's channel, service and mailer, then numbers the piece. The label's Intelligent Mail Package Barcode, or IMpb, holds it, preferably joined to the routing ZIP Code every label must carry. The label also shows the service with its postage, both addresses and an Intelligent Mail Matrix Barcode, or IMmb, with the same data. - [Intelligent Mail Package Barcode (IMpb)](https://postalref.com/products/impb.md) - [Intelligent Mail Matrix Barcode](https://postalref.com/products/intelligent-mail-matrix-barcode.md) ### [Paying for packages: manifests, eVS and USPS Ship](https://postalref.com/guides/package-payment.md) Shippers pay package postage by sending USPS a manifest, an electronic Shipping Services File that lists each package's weight, size and postage. USPS Ship, which replaced eVS, charges that postage to the shipper's Enterprise Payment Account. It then compares each package's measured weight and size with the manifest, and charges or refunds the difference. - [Electronic Verification System (eVS®)](https://postalref.com/products/evs.md) - [USPS Ship](https://postalref.com/products/usps-ship.md) - [Automated Package Verification (APV) System](https://postalref.com/products/automated-package-verification-apv-system.md) ### [Return labels and return services](https://postalref.com/guides/returns.md) A business gives its customers prepaid USPS return labels, and the business, not the customer, pays the postage for each package that comes back. USPS Returns prices each returned package and charges the business at the delivery scan. Parcel Return Service lets a shipper collect returns in bulk, and Bulk Parcel Return Service brings back USPS Marketing Mail parcels. - [USPS Returns](https://postalref.com/products/usps-returns.md) - [Merchant Returns API](https://postalref.com/products/merchant-returns-api.md) - [Bulk Parcel Return Service](https://postalref.com/products/bulk-parcel-return-service.md) ### [USPS APIs and shipping software](https://postalref.com/guides/shipping-apis.md) The USPS APIs let a business's software verify addresses, price and label packages, and track them. Developers get access through the USPS Developer Portal and test in a separate environment before production. Click-N-Ship prints labels with postage on usps.com, and the Parcel Data Exchange API moves manifest files between a shipper's software and USPS. - [Parcel Data Exchange (PDX) API](https://postalref.com/products/parcel-data-exchange-pdx-api.md) - [Tech Sheets for APIs, Click-N-Ship, and USPS Ship](https://postalref.com/products/tech-sheets-for-apis-click-n-ship-and-usps-ship.md) ### [Mailability: hazardous, restricted and perishable items](https://postalref.com/guides/mailability.md) USPS refuses anything that may kill or injure someone or damage the mail, and accepts some hazardous, restricted and perishable items only under the conditions of its rulebook, Publication 52. Permitted hazardous materials carry warning labels, the proper shipping name and the UN number on the address side, and hazardous materials codes in the barcode. - [Hazardous, Restricted, and Perishable Mail](https://postalref.com/products/mailability.md) ## Tracking and visibility ### [Package tracking, scan events and proof of delivery](https://postalref.com/guides/package-tracking.md) USPS reports where a package is through scan events, which Product Tracking and Reporting stores from acceptance to delivery and the USPS Tracking website shows. Shippers also get the events by API, webhook or file, can stop or redirect a package in transit, and can get proof of delivery. - [Product Tracking and Reporting (PTR)](https://postalref.com/products/ptr.md) - [Bulk Proof of Delivery Program](https://postalref.com/products/bulk-proof-of-delivery-program.md) - [Package Intercept](https://postalref.com/products/package-intercept.md) - [Phone Provider Format–Hold For Pickup Notifications](https://postalref.com/products/phone-provider-format-hold-for-pickup-notifications.md) ### [Mail tracking: IV-MTR, IMb Tracing and Informed Delivery](https://postalref.com/guides/mail-visibility.md) Mailers track letters, flats and their containers in Informed Visibility Mail Tracking & Reporting, IV-MTR, a free USPS application built on scan data. Its logical delivery events show, in near real time, when pieces reach the recipient. Informed Delivery shows consumers images of their letter mail before it arrives, and mailers can add images and a link. - [Informed Visibility Mail Tracking & Reporting](https://postalref.com/products/iv-mtr.md) - [Mail Quality Data through IV-MTR](https://postalref.com/products/mail-quality-data-through-iv-mtr.md) - [Service Performance Measurement (SPM) Mail Exclusions](https://postalref.com/products/service-performance-measurement-spm-mail-exclusions.md) - [Informed Delivery](https://postalref.com/products/informed-delivery.md) - [Informed Delivery API](https://postalref.com/products/informed-delivery-api-application-programming-interface.md) ## Address quality ### [Address matching: CASS, DPV and USPS address data](https://postalref.com/guides/address-matching.md) CASS-certified address-matching software standardizes an address and matches it to USPS's ZIP + 4 and City State Products to assign its ZIP + 4 and delivery point codes. DPV then confirms whether USPS delivers to the address, and LACSLink and SuiteLink supply converted addresses and missing suite numbers. - [CASS](https://postalref.com/products/coding-accuracy-support-system.md) - [Multi-line Accuracy Support System](https://postalref.com/products/multi-line-accuracy-support-system.md) - [Address Matching System API](https://postalref.com/products/ams-api.md) - [DPV](https://postalref.com/products/delivery-point-validated.md) - [LACSLink](https://postalref.com/products/lacslink.md) - [SuiteLink®](https://postalref.com/products/suitelink.md) - [DSF2](https://postalref.com/products/dsf2.md) - [Address Information System products](https://postalref.com/products/address-information-system.md) - [Address Element Correction and AEC II](https://postalref.com/products/address-element-correction.md) - [County Project](https://postalref.com/products/county-project.md) ### [Move Update: NCOALink and keeping lists current](https://postalref.com/guides/move-update.md) The Move Update standard requires mailers claiming commercial First-Class Mail or USPS Marketing Mail prices to update their addresses with a USPS-approved method within 95 days before mailing. NCOALink updates a list before mailing, Address Change Service and ancillary service endorsements report moves after it, and First-Class Mail has two alternative methods. - [Move Update](https://postalref.com/products/move-update.md) - [NCOALink](https://postalref.com/products/ncoalink.md) - [ANKLink](https://postalref.com/products/anklink.md) ### [Undeliverable mail: forwarding, endorsements and ACS](https://postalref.com/guides/undeliverable-mail.md) USPS forwards, returns or discards mail that is undeliverable as addressed, depending on its mail class, the mailer's endorsement and any change-of-address order. The mailer finds out from the returned piece, a printed notice such as PS Form 3547, or an electronic notice from the Address Change Service. - [Address Change Service](https://postalref.com/products/address-change-service.md) - [OneCode ACS](https://postalref.com/products/onecode-acs.md) - [Traditional ACS](https://postalref.com/products/traditional-acs.md) - [Intelligent Mail Package Barcode (IMpb) ACS](https://postalref.com/products/intelligent-mail-package-barcode-impb-acs.md) - [Shipper Paid Services](https://postalref.com/products/shipper-paid-services.md) - [Ancillary Service Endorsements](https://postalref.com/products/ancillary-service-endorsement.md) - [Secure Destruction](https://postalref.com/products/secure-destruction.md) - [Premium Forwarding Service Commercial](https://postalref.com/products/premium-forwarding-services-commercial.md) ## Accounts and payment ### [Business accounts: BCG, CRID and Mailer ID](https://postalref.com/guides/business-accounts.md) A business opens a USPS business account on the Business Customer Gateway or the Business Portal, which assign it a Customer Registration ID, or CRID, and a Mailer ID. Each CRID identifies one business location and owns its Mailer IDs. A Business Service Administrator at the location decides who may use each of its services. - [Business Customer Gateway](https://postalref.com/products/business-customer-gateway.md) - [Business Portal](https://postalref.com/products/business-portal-formerly-customer-onboarding-portal.md) - [Customer Registration ID (CRID)](https://postalref.com/products/crid.md) - [Mailer Identifier (MID)](https://postalref.com/products/mid.md) - [Enterprise Post Office Boxes Online](https://postalref.com/products/enterprise-post-office-boxes-online.md) ### [Paying for postage: permits, meters, PC Postage and EPS](https://postalref.com/guides/paying-postage.md) Businesses pay USPS for postage with stamps, a postage meter or PC Postage, or a permit imprint, and the mark on each mailpiece shows which method paid. Permit imprint postage comes out of an advance deposit account held with USPS, which a business can fund through the Enterprise Payment System. - [Enterprise Payment System](https://postalref.com/products/enterprise-payment-system.md) - [Postage Evidencing Systems](https://postalref.com/products/pes.md) - [USPS Picture Permit Indicia](https://postalref.com/products/usps-picture-permit-indicia-ppi.md) - [Mail Anywhere](https://postalref.com/products/mail-anywhere.md) - [Stamp Fulfillment Services](https://postalref.com/products/sfs.md) ## Operations ### [Mail entry: facilities, drop shipment and appointments](https://postalref.com/guides/mail-entry.md) Mailers enter business mail at a Business Mail Entry Unit, at a Detached Mail Unit in their plant, or at a facility near its destination. Entering mail closer to delivery generally earns a lower postage price. Drops at USPS processing facilities and service hubs need an appointment in FAST, the Facility Access and Shipment Tracking system. - [Drop Shipment Management System](https://postalref.com/products/dsms.md) - [Facility Access and Shipment Tracking (FAST®)](https://postalref.com/products/fast.md) - [Service Hubs and Facilities](https://postalref.com/products/service-hubs-and-facilities.md) ### [Mail processing: how USPS sorts and moves mail](https://postalref.com/guides/mail-processing.md) Inside USPS, processing plants sort mail in phases, first toward its destination and then down to a carrier's route, and a carrier delivers it. Mail moves between plants on dispatches timed to meet service standards, USPS's delivery goals for each class, usually counted in days. ## Promotions ### [Mailing promotions and incentives](https://postalref.com/guides/promotions.md) USPS mailing promotions take a percentage off First-Class Mail and USPS Marketing Mail postage for mailpieces using a technology or print treatment USPS rewards. Mailers get each mailpiece pre-approved in the My Products Portal, then register on the Business Customer Gateway. Mail Growth Incentives pay postage credit for volume growth, and the Marriage Mail Incentive is a 20% discount. - [Mailing Promotions and Incentives](https://postalref.com/products/mailing-promotions.md) - [Mail Growth Incentives](https://postalref.com/products/mail-growth-incentives.md) - [My Products Portal](https://postalref.com/products/my-products-portal.md) ## Help and the industry ### [Getting help from USPS: help desks, centers and councils](https://postalref.com/guides/getting-help.md) A business mailer reaches USPS through help desks for its online systems, local offices and analysts for its mailings, and a national center for rulings. The PostalOne! Help Desk supports the Business Customer Gateway, and the Mailing and Shipping Solutions Center helps with payment accounts. Mailers advise USPS through Postal Customer Councils, the Mailers’ Technical Advisory Committee and the National Postal Forum. - [Pricing and Classification Service Center](https://postalref.com/products/pricing-and-classifications-service-center.md) --- Unofficial. Not affiliated with or endorsed by the United States Postal Service. This is https://postalref.com/guides as Markdown.