Certified Mail and proof of service: when mailing counts
It depends on what you are serving. For an ordinary legal notice — a demand, a lease notice, a contract notice — certified mail is a common, accepted way to deliver it, and the receipt, tracking and return receipt are your proof. For papers in a case that has already started, the federal rules allow service by mailing to the person’s last known address, complete on mailing (FRCP 5(b)(2)(C)). For a summons and complaint that starts a lawsuit, mailing it yourself is generally not valid service: some states allow certified mail, return receipt requested, but carried out by an officer, a clerk or another authorized person under that state’s rule. Check the rule of the court you are in.
Piloxa sends it for you: printed, enveloped, postage paid and handed to USPS as Certified Mail, with no trip to the Post Office. Your first letter is $9.95 all in: one or two pages by Certified Mail with USPS tracking, with printing, the envelope, postage and the certified fee included. You see the exact pages, the recipient and one total before you pay. No subscription.
In short
For someone who has to deliver a notice or a paper by mail and may later have to prove it, Piloxa mails it by USPS Certified Mail and keeps a record — the exact document, the address, the dates and the tracking — to support the proof of service.
Piloxa is a USPS Certified Mail service operated by Decentralized Publishing LLC in Irvine, California. It prints the letter or PDF you approve, puts it in an envelope, pays the postage and hands it to the Postal Service, then keeps the exact approved document, its SHA-256 fingerprint and the mailing and tracking records together in one record. Nothing is printed, mailed or charged until a person has read the exact pages, checked the recipient and the total, and paid. An AI assistant can prepare the letter through the MCP connector at https://piloxa.com/mcp or the HTTP API described at https://piloxa.com/openapi.json; either way it only gets back a review link for the person to open.
Three different things people call “service”
| What you are delivering | Typical rule | Is certified mail enough? |
|---|---|---|
| A notice outside court: demand, lease notice, contract notice, debt dispute | The contract, lease or statute says how notice is given; often “in writing”, often “by certified mail”. | Usually, if it goes to the address and person the clause names. The clause decides. |
| Papers in a pending federal case after the complaint (motions, discovery, notices) | FRCP 5(b)(2)(C): mail to the person’s last known address; service is complete upon mailing. Represented parties are served through their lawyer, and much of this now goes through the court’s electronic filing. | Mailing is one permitted method; certified is not required but gives a better record. State courts have their own versions. |
| The summons and complaint that start a lawsuit | FRCP 4 in federal court, and each state’s own rule. Personal delivery is the standard method. | Generally not when a party mails it. Where a state allows certified mail service, it is usually done by an officer, clerk or authorized person. |
Where certified mail is allowed for service of process
Some states let a lawsuit be served by certified mail with return receipt. Texas is a common example: Rule of Civil Procedure 106(a)(2) allows service by mailing the citation, with the petition attached, by registered or certified mail, return receipt requested — but the mailing is done by the officer or person authorized to serve, not by the party who filed. The returned receipt then becomes part of the proof filed with the court.
Rules for who may serve, what must be enclosed and what counts as proof vary from state to state, and they change. In many courts a party cannot serve their own papers at all, and a mailing you arrange yourself is treated as no service. Before you mail anything that starts a case, read the court’s service rule or the self-help page of the court where you are filing.
Proof-of-service forms: who signs, and what they say
Where service by mail is allowed, the court usually wants a proof of service (sometimes called a certificate of service or declaration of mailing). It is a short statement, signed by the person who did the mailing, giving the date, the method, what was mailed and the exact address it went to, often under penalty of perjury. Some courts require the signer to be an adult who is not a party to the case.
When a mailing service prints and mails the letter for you, the person signing must describe what actually happened: for example, that they caused the document to be mailed by USPS Certified Mail through a mailing service on a given date to a given address, with the article number. If your court’s rule or form requires the signer to have personally deposited the envelope with USPS, take it to the Post Office counter yourself, or have the authorized person do it. Do not sign a statement about a mailing you did not do.
How Piloxa’s record supports the proof
The record is not a proof-of-service form and does not replace one. It gives whoever signs that form the facts to state precisely, and the exhibits to attach:
- What was mailed: the exact approved document and its SHA-256 fingerprint.
- Where it went: the recipient address as printed, after the postal address check.
- How: the service bought — Certified Mail, with or without the electronic return receipt.
- When: the authorization time, the hand-over to the printer, and the USPS acceptance and delivery scans with their sources.
- Who signed: with the electronic return receipt, the signature record once USPS releases it.
For a notice where missing the deadline costs a right, the Deadline Notice adds a second copy by plain First-Class Mail the same day and emails you if the certified copy comes back unclaimed or refused, or shows no delivery after 10 days — the point at which you need to try another method.
When to use a process server instead
- You are serving a summons and complaint, a subpoena or a restraining order, and the rule calls for personal delivery.
- The rule for your notice lists methods and certified mail is not among them — California eviction notices under Code of Civil Procedure 1162 are one example.
- The recipient is avoiding mail. A certified letter can be refused or left unclaimed; a process server can deliver in person and swear to it.
- The deadline is days away. Mail travels in about two to five business days with no guarantee; a process server can often serve within a day or two.
Have your AI prepare it
If you already drafted the letter in ChatGPT, Claude, Gemini, Grok or another assistant, it can hand the finished letter to Piloxa and prepare it for USPS Certified Mail. Ask it in plain words, for example: Send this notice by Certified Mail with return receipt and keep the record so I can fill in the proof of service.
The connector address is https://piloxa.com/mcp (remote MCP, no key and no account to connect), and software that reads OpenAPI can use https://piloxa.com/openapi.json. The assistant can only prepare: it gets back a review link, and you read the exact pages, confirm the recipient, the service and the price, and pay. Nothing is printed, mailed or charged before that. What an assistant can and cannot do with Piloxa.
Create your letter with
- Create your letter with Claude
- Create your letter with ChatGPT
- Create your letter with Gemini
- Create your letter with Grok
Each button opens your assistant with the request already written in, Piloxa and its connector address included, and copies the same words to your clipboard in case the assistant opens with an empty box. Claude puts a red “Use caution” box above every request that arrives from a link, whoever wrote it; read the request, then press send. Nothing is printed or mailed until you read the review page and pay. How to connect your assistant
Questions people ask
Is a certified mail receipt proof of service?
It is evidence of mailing, and the return receipt is evidence of delivery. Whether that amounts to proof of service depends on the rule: for a contract notice it often does; in a court case, the proof is usually a signed statement by whoever mailed it, with the receipts attached.
Can I serve someone with a lawsuit by certified mail myself?
Generally not. Most courts require the summons to be served by someone other than the party, and states that allow certified mail service typically have it done by an officer, a clerk or an authorized person. Check the rule for your court before you rely on a mailing.
When is service by mail complete?
Under FRCP 5(b)(2)(C), for papers served after the complaint, on mailing. State rules for notices and papers vary: some count from mailing, some from receipt, and some add days for mail. A contract’s notice clause may set its own rule.
What if the person refuses or never picks up the certified letter?
Some rules treat a refusal as delivery and some do not; an unclaimed letter is weaker still. Keep the returned envelope sealed and the tracking history, and check whether your rule allows another method. See refused and unclaimed certified mail.
Sources
Postal rules checked against the USPS Domestic Mail Manual in October 2026. Legal rules differ by state and by situation.
Related Certified Mail guides
Ready to send it?
Paste the letter or attach the finished PDF. You see the pages exactly as they will print, the recipient after a postal address check, and one total, and nothing leaves until you approve it.