When mailing time-sensitive or legally required documents, it’s essential to have reliable proof that your letters were sent. For legal, real estate, healthcare, and government professionals, this isn’t just a best practice—it’s a requirement.
Understanding Certificate of Mailing vs. Affidavit of Mailing
Two of the most trusted methods for proof of mailing are the Certificate of Mailing and the Affidavit of Mailing. While they may sound similar, they serve different purposes and are used in different circumstances.
In this guide, we’ll break down the differences, benefits, and best-use scenarios of each. Plus, show you how Send Certified Mail helps you streamline both with zero added cost.
What Is a Certificate of Mailing?
USPS-Issued Mailing Proof
A Certificate of Mailing is an official document issued by the United States Postal Service (USPS) when you send a letter or package. It shows the date an item was mailed, the recipient’s address, and confirms that USPS accepted it into the mail stream.
It does not track delivery or provide signature confirmation. Instead, it’s used as proof that the sender fulfilled their obligation to mail the item on time.
Key Benefits
- Provides a USPS-issued timestamp
- Accepted as proof in legal and administrative matters
- Required for many court filings and tenant notifications
- Automatically available for Certified and First-Class Mail
What Is an Affidavit of Mailing?
A Self-Certified Mailing Statement
An Affidavit of Mailing is a signed document (often under oath) completed by the sender that verifies they mailed a document to a specific recipient on a specific date. While not issued by USPS, this document is often accepted as reliable legal evidence—especially when notarized.
With Send Certified Mail, Affidavits of Mailing are generated upon selection and archived for 10 years, accessible at any time.
Key Benefits
- Useful when third-party documentation isn’t required
- Accepted in many courts and business settings
- Strengthens your compliance documentation trail
- Free and automated with all mailings from Send Certified Mail
When to Use Each Type of Proof
Both documents provide value, but depending on the situation, one may be more appropriate than the other.
Use Certificate of Mailing When:
- USPS-issued evidence is required
- You’re dealing with legal filings, lease terminations, or regulated notices
- Mailing time-sensitive documents under landlord-tenant laws (like in Washington)
- You want an official postmark and third-party validation
Use Affidavit of Mailing When:
- Internal compliance or policy requires a sworn statement
- The court or agency accepts affidavits as valid proof
- USPS documentation is not needed or available
- You want an additional layer of verification for your records
How Send Certified Mail Provides Both—At No Extra Cost
At Send Certified Mail, we believe that every business should have access to comprehensive mailing proof, without paying extra for it. That’s why we offer both a Certificate of Mailing and an Affidavit of Mailing with every Certified Mail and First-Class Mail sent through our platform.
Our Proof of Mailing Services Include:
- Certificate of Mailing: USPS postmarked and timestamped
- Affidavit of Mailing: Signed and notarized declaration stored with each selected record
- 10-Year Data Archive: Full record, available 24/7-365 for audit and compliance support
- Secure Access: Bank-grade encryption
- Zero Cost: Included with your pay-as-you-mail service
Whether you send a single eviction notice or thousands of monthly invoices, your documentation is complete, compliant, and secure.
Available for Both Certified Mail and First-Class Mail
Many mail platforms limit these services to Certified Mail only. At Send Certified Mail, both the Certificate of Mailing and the Affidavit of Mailing are available for First-Class Mail as well.
This is especially valuable for property managers, attorneys, and HOAs who send a high volume of notices that don’t require delivery confirmation, but still demand reliable proof of mailing.
Compare the Certificate and Affidavit of Mailing
|
Feature |
Certificate of Mailing |
Affidavit of Mailing |
|
Issued By |
USPS |
Sender |
|
Proof Type |
USPS Issued Receipt |
Signed Declaration |
|
Delivery Confirmation |
❌ |
❌ |
|
Archival Access |
10 years, free |
10 years, free |
|
Available for First-Class Mail |
✅ |
✅ |
|
Common Uses |
Court filings, tenant notices |
Internal policy, supplementary proof |
Why Legal and Property Professionals Rely on Send Certified Mail
Hundreds of thousands of businesses nationwide rely on Send Certified Mail to manage their U.S. Mail communications. From law firms and real estate companies to government agencies and healthcare providers, we provide the documentation and automation tools needed for compliance and peace of mind.
With no monthly fees, long-term contracts, or complicated setup, our platform streamlines secure mailings from any location.
Bonus: In-State Postmarks for Legal Compliance
If your legal requirements demand that your mail be postmarked in Washington—under its new Landlord-Tenant Act—we’ve got you covered.
Send Certified Mail prints and mails from within the state of Washington, ensuring that both your Certificate of Mailing and postmark meet in-state compliance standards.
Mail Smarter, Not Harder—with Automation
Want to go further? You can automate your mailings with our batch tools and SFTP integrations, ideal for recurring documents like:
- Rent notices
- Legal disclosures
- Billing statements
- Internal compliance letters
No manual handling. No delays. Just fast, secure, and trackable mail.
Get Proof, Stay Compliant, and Save Time
When it comes to proof of mailing, don’t settle for one-size-fits-all. Use both a Certificate of Mailing and an Affidavit of Mailing to fully protect your business and ensure compliance.
With Send Certified Mail, you get both at no extra cost. Combine that with same-business-day mailing, 10-year data archives, and secure access from anywhere, and you’ve got the most complete online mail solution available.
About Send Certified Mail
Send Certified Mail is the leading web-based platform for mailing USPS Certified, First-Class, Priority, and Express Mail letters online. We help law firms, property managers, and regulated businesses send secure, compliant mail without printers and postage meters. Skip the trip to the mail room and Post Office with Send Certified Mail.
Learn more or send your first letter today. Schedule a free Live Demo now.