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Free New York Certification of Mailing

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New York Certification of Mailing — a sworn statement that a notice or document was mailed. Use it to record the certified and first-class mailings that complete substituted or conspicuous-place service under RPAPL § 735(1).

Certification of Mailing RPAPL § 735(1) New York Free PDF

A New York certification of mailing is a template you complete truthfully and swear before a notary to prove that a notice or document was actually put in the mail. It states who mailed it, what was mailed, to whom, at what address, on what date, and by what class of mail. Proof of mailing matters in New York because many notices must be documented to be effective — most notably the mailings that RPAPL § 735(1) requires after substituted or conspicuous-place (“nail and mail”) service in a summary proceeding. This certification is a sworn statement; it is different from the USPS Certificate of Mailing (PS Form 3817), which is an official postal receipt. It is not legal advice.

Complete the fields below to generate a New York certification (affidavit) of mailing. Fill it in truthfully, print it, and sign it before a notary public so the statement is sworn; then attach your postal receipts and keep a copy.

A certification of mailing — often called an affidavit of mailing — is a written statement, completed truthfully and sworn before a notary, that a particular document was placed in the mail. It answers a narrow but important question: can you prove the mailing happened, and prove the details of it? In New York landlord-tenant practice the answer often decides a case, because service of a summary proceeding and many predicate notices are not complete until a required mailing is done and documented. The generator above builds a certification you can complete, notarize, and keep with the postal receipts; the guide below explains what New York law requires and how this document fits alongside the official court forms.

This page describes the general mechanics of a certification of mailing and the specific RPAPL § 735(1) mailing rule that most often makes it necessary in a New York eviction. It does not attempt to state every mailing requirement in New York law — other notices in other contexts carry their own rules — so treat the § 735(1) discussion as the verified anchor and confirm any other requirement against the statute that governs your notice.

At its core the certification is a sworn factual account of a mailing. The person who did the mailing (the affiant) states, in the first person, that on a stated date they deposited a described document, addressed to a named recipient at a stated address, in a depository under the exclusive care of the United States Postal Service, and that they used a stated class of mail. Because it is sworn before a notary, the affiant is representing those facts under oath, which is what gives the document its evidentiary weight.

Two features make it useful. First, it is contemporaneous and specific: it captures the exact address, date, and mail class while the memory is fresh and the receipt is in hand, rather than reconstructing them months later at a hearing. Second, it is self-authenticating in practice: paired with the postal receipts, a properly sworn certification lets a court accept that the mailing occurred without the mailer having to testify live in most uncontested matters. It does not, by itself, prove the recipient received or read the document — only that it was mailed as described.

The certification is not the same as the underlying document it describes. If you mailed a notice of petition, a rent demand, or an order, the certification is a separate cover statement about that mailing; the mailed papers are attached or referenced. Keeping the two clearly distinct — the sworn statement on top, the proof of what was mailed underneath — is what makes the record easy for a clerk or judge to follow.

Proof of mailing matters whenever a rule makes a mailing part of what counts as valid service or valid notice. In New York landlord-tenant matters the most common trigger is RPAPL § 735(1), which requires mailings to complete service of a notice of petition and petition when the papers were served by substituted service or by conspicuous-place (“nail and mail”) service. Because service by those alternative methods is not complete until the mailings are done and proof is filed, the certification is not a formality — it is a link in the chain that makes the whole proceeding valid.

Beyond § 735, mailing questions come up in other landlord-tenant settings: documenting that a predicate notice was mailed to the tenant, that a security-deposit statement was sent, or that some other notice the parties agreed to send in writing actually went out. The details a certification captures — date, address, class of mail, and receipt number — are the same facts a court or the other side will ask about. Recording them once, under oath, at the time of mailing, is far more reliable than trying to prove them later.

Landlords who are organizing a case will usually pair this certification with two other records: an affidavit of service covering the personal delivery or posting step, and the postal receipts covering the mailing step. Together those three documents describe the complete service process from start to finish, which is exactly what a court needs to see.

These two are easy to confuse because the names overlap, but they are different documents that do different jobs. An affidavit (certification) of mailing is your own sworn statement; a USPS Certificate of Mailing (PS Form 3817) is an official receipt from the post office. The strongest proof usually uses both: the affidavit tells the story of the mailing under oath, and the postal receipt corroborates it with a postmark.

• Who creates it. The affidavit of mailing is created by the mailer and sworn before a notary. The Certificate of Mailing is created by the Postal Service, which postmarks PS Form 3817 and hands it back to you as your receipt.
• What it proves. Both establish that an item was mailed on a given date. Neither proves delivery: a USPS Certificate of Mailing expressly does not provide a record of delivery, and no signature is obtained. If you need proof of delivery, that is a separate service (for example, certified mail with return receipt).
• Whether a copy is kept. The Postal Service does not retain a copy of PS Form 3817, so the receipt it returns to you is the only copy — losing it is losing the proof. Your notarized affidavit, by contrast, is a document you keep and can re-print.
• How they work together. For a § 735(1) mailing, landlords commonly send the copies by certified (or registered) mail and by first-class mail, keep the certified receipt and any Certificate of Mailing, and then describe all of it in a sworn certification. The receipts back up the affidavit; the affidavit organizes and swears to the receipts.

A useful certification of mailing captures every fact a court or opposing party would want to verify. Leave a blank and you invite a dispute; fill each one accurately and the mailing is easy to prove.

• The affiant. The name and role of the person who actually did the mailing — the mailer swears to what they personally did, so it should be signed by that person, not by someone reporting on it secondhand.
• The document mailed. A specific description of what went in the envelope — for example, “Notice of Petition and Petition” or a named predicate notice — so there is no doubt about what was served.
• The recipient and address. The recipient’s name and the exact address used, which for a § 735(1) mailing means the address the statute directs (the property, plus a known residence or business address where required).
• The date mailed. The precise date the item was deposited with the Postal Service — the fact the one-day § 735(1) window turns on.
• The class of mail. Whether the copies went by certified or registered mail and by regular first-class mail; § 735(1) requires both, so record both.
• The place of mailing and receipts. The post office or location it was mailed from, plus certified/tracking numbers, so the sworn account and the postal records line up.
• The verification and jurat. A dated signature by the affiant and the notary’s jurat, which is what makes the statement a sworn affidavit rather than an unsworn note.

The rule that most often makes this certification necessary is RPAPL § 735(1). When a notice of petition and petition in a summary proceeding are served by substituted service (delivery to a person of suitable age and discretion at the property) or by conspicuous-place service (affixing the papers to a conspicuous part of the premises when personal and substituted service fail), the petitioner must also mail copies of the papers to the respondent. This is why the “nail and mail” method is only half done at the door — the mailings are the other half.

Section 735(1) requires two mailings of the same papers to each respondent: one by registered or certified mail and one by regular first-class mail. Both must be sent within one day after the delivery or affixing. For a natural person, the papers are mailed to the respondent at the property, and, if the petitioner has written information of a residence address or last-known business address, to that address as well. The certification you generate on this page is designed to record exactly these facts — the two classes of mail, the address used, and the date — so the § 735(1) mailing can be proven.

Under RPAPL § 735(2), when service is made by the substituted or conspicuous-place method, service is complete upon the filing of proof of service, and the proof of service must be filed with the court within three days after the mailing. Personal delivery, by contrast, is complete immediately. Because the completeness of service — and the clock for the respondent’s time to answer — can hinge on when proof is filed, documenting the mailing promptly and filing on time is essential.

• Missing the one-day mailing window. Under § 735(1) the mailings must go out within one day of the delivery or affixing; a late mailing can defeat the service.
• Sending only one class of mail. Both a certified (or registered) mailing and a first-class mailing are required — sending just one is a frequent defect.
• Using the wrong address. Mailing to an outdated or incorrect address, or omitting a known residence or business address the statute directs, undermines the service.
• Losing the postal receipts. Because the Postal Service does not keep a copy of a Certificate of Mailing, a lost receipt can leave you unable to corroborate the sworn certification.
• Not swearing the certification. An unsworn note about the mailing carries far less weight than an affidavit signed before a notary; skipping the jurat weakens the proof.
• Filing proof late. For substituted or posted service, proof of service must be filed within three days of the mailing; a late filing can delay when service is deemed complete.
• Confusing the certification with the notice. The certification proves the mailing; it does not replace a defective or premature underlying notice.

• Mail both classes on the same day the § 735(1) clock starts, and note that date exactly on the certification.
• Get a Certificate of Mailing or certified receipt at the counter and staple it to the certification the same day.
• Use the address the statute directs — the property plus any known residence or business address — and double-check the spelling and ZIP.
• Record the tracking numbers so the sworn account and the postal records match line for line.
• Sign before a notary so the statement is a sworn affidavit, and confirm whether your court accepts an attorney affirmation instead.
• File proof of service on time — within three days of the mailing — and keep a stamped copy.
• Screen tenants before the tenancy so you are less likely to reach the eviction stage where these mailings matter.

Once the certification is filled in, print it and sign it before a notary public, who completes the jurat; that step converts it from a note into a sworn affidavit. Attach the postal receipts — the certified-mail receipt, the return receipt if you requested one, and any USPS Certificate of Mailing — directly behind the certification so the paper trail stays together. Keep the whole packet with the underlying notice or petition it supports.

Where the mailing completes service under RPAPL § 735, file the proof of service with the court within three days of the mailing, because for substituted or conspicuous-place service the case treats service as complete only upon that filing. Calendar the answer date that runs from completed service, and hold onto your copies through the life of the proceeding and any appeal period. If the matter is contested, or if you are unsure whether § 735(1) even applies to your notice, treat this certification as a preparation tool and have a qualified New York attorney or the court’s help center confirm the method and timing before you rely on it.

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