Not every document in a California family law case has to be handed to the other party in person. Many filings, once your case is underway, can be served by mail instead, and Form FL-335, Proof of Service by Mail, is how you tell the court that it happened.
Key Takeaway: FL-335 proves that a document was mailed to the other party in your case. It is completed by the adult who did the mailing, who cannot be a party to the case. It is not used for the initial Petition and Summons, which generally require personal service proven with Form FL-115.
Form FL-335 is the California Judicial Council form titled "Proof of Service by Mail." It is a short declaration, completed under penalty of perjury, that tells the court:
- What document (or documents) were served
- Who they were mailed to, and at what address
- The date and location the mailing took place
- Who did the mailing, confirming they were an adult and not a party to the case
Without a completed and filed proof of service, the court has no formal record that the other party ever received your paperwork, even if they actually did.
California family law distinguishes between two ways of getting documents to the other party, and the rules depend on which document you're serving.
Personal Service
Personal service means physically handing the documents to the other party (or leaving them in a way the law allows if the person refuses to take them). The initial Petition and Summons that open a divorce, legal separation, or custody case generally require personal service. That service is proven with Form FL-115, Proof of Personal Service, not FL-335. If you're working through that first step of a case, our guide on How to Fill Out Form FL-115 walks through it in detail.
Service by Mail
Once a case has started and the other party has appeared or been properly served with the initial papers, many later documents (declarations, responses to routine motions, financial disclosures, and other ongoing filings) can generally be served by regular mail instead. That's where FL-335 comes in: it proves the mailing happened.
Not every document qualifies for mail service. If you're unsure whether a specific filing requires personal service or allows mail service, check the instructions on that form or ask your county Superior Court self-help center before you serve it.
The person who mails the documents, and who signs FL-335, must meet two requirements:
- They must be an adult, at least 18 years old
- They must not be a party to the case
This means neither spouse (or parent, in a custody matter) can mail their own documents and sign the proof of service for that mailing. A friend, relative, coworker, or paralegal who is not involved in the case as a party can do it, as can a legal document preparation service.
<h2 id="what-can-be-served-by-mail">What Documents Can Be Served by Mail</h2>Many of the documents filed after a case opens allow for mail service, since the parties are already known to be involved in the case and, in most instances, have already appeared or been served with the original Petition and Summons. Examples often include routine declarations, responses to certain motions, and other ongoing paperwork required as a case moves toward judgment.
The initial documents that start a case, the Petition and Summons, are the clearest example of the opposite rule: they generally require personal service, proven with FL-115, precisely because the other party has not yet been formally brought into the case. If you're not sure whether a document you need to serve allows mail service, the safest step is to confirm with your county's self-help center or the instructions printed on the form itself.
<h2 id="section-by-section">Section-by-Section Walkthrough of FL-335</h2>Here's what the server actually fills in on FL-335.
1. Case Information
At the top, enter the county, the names of the Petitioner and Respondent, and the case number. This ties the proof of service to the correct case file.
2. Documents Served
List each document that was mailed. Be specific, using the exact title of each form or paper (for example, "Declaration re Income and Expenses" rather than a general description). If more than one document was mailed in the same envelope on the same day, they can typically be listed together.
3. Person Served
Enter the full name of the person the documents were mailed to, and the complete mailing address used. Accuracy here matters: if the address is wrong or incomplete, the mailing may not be valid service at all.
4. Date and Place of Mailing
State the date the documents were placed in the mail, and the city (and generally the state) where the mailing occurred, meaning where the envelope was deposited, such as at a post office or mailbox.
5. Server's Declaration and Signature
The person who did the mailing declares, under penalty of perjury under the laws of the State of California, that the information on the form is true and correct. They then print their name, the date, and sign the form. This declaration is what gives the document its legal weight; it is a sworn statement, not just a note for the file.
<h2 id="filing-the-proof">Filing the Completed Proof of Service</h2>Completing FL-335 is only half the job. The signed proof needs to actually reach the court:
- Confirm the form is fully filled out and signed by the server, not a party
- Make a copy for your own records before filing
- File the completed FL-335 with the clerk of the same Superior Court handling your case
- Keep the filed copy (often stamped by the clerk) as your record that service is documented
A signed proof of service sitting in a drawer does nothing for your case. The court only recognizes that service happened once the completed FL-335 is actually filed.
If you're weighing whether to handle service and filing steps like this yourself throughout your case, our guide on How to File for Divorce in California Without a Lawyer covers the broader self-represented process.
<h2 id="common-mistakes">Common Mistakes to Avoid</h2>- A party to the case mailing their own documents and signing the proof of service themselves
- Using mail service for a document that actually requires personal service, such as the initial Petition and Summons
- Listing an incomplete or outdated mailing address for the person served
- Leaving off one or more documents that were actually included in the same mailing
- Forgetting to file the completed and signed FL-335 with the court
- Signing before the mailing actually took place, rather than after
What is Form FL-335 used for?
Form FL-335, Proof of Service by Mail, documents that a specific court paper was mailed to the other party in a family law case. It is completed and signed by the adult who did the mailing, and it becomes the court's record that service happened, when, and how.
Can I use FL-335 to serve my initial divorce Petition and Summons?
Generally, no. The document that opens a case, the Petition and Summons, generally requires personal service, proven with Form FL-115, Proof of Personal Service. FL-335 is for the many documents filed after the case has started, once mail service is allowed for that particular filing.
Who can complete and sign Form FL-335?
The person who mailed the documents completes and signs FL-335. That person must be at least 18 years old and must not be a party to the case. A party cannot mail their own papers and sign the proof of service for them, even if the mailing itself was accurate.
What information goes on FL-335?
FL-335 asks for the name and address the documents were mailed to, the date of mailing, the location the mailing was placed (such as the city where it was deposited in the mail), a list of the documents served, and the server's declaration under penalty of perjury, followed by their signature.
Does the completed FL-335 need to be filed with the court?
Yes. A signed proof of service that is never filed does not help you. The court only has evidence that service occurred once the completed FL-335 is filed with the clerk, generally attached to or referencing the document it proves was served.
What happens if I use mail service when personal service was required?
If a document required personal service and it was instead only mailed, the court can find that service was defective. That can delay your case, require you to serve the document again correctly, or, for documents like the initial Petition and Summons, prevent the case from moving forward until proper service is completed.
Can the same person mail documents and also be listed as a party?
No. The mailing must be done by someone who is not a party to the case. This keeps the proof of service credible, since the court is relying on a neutral third party's declaration that the mailing actually happened as described.
How Virdix Helps With Proof of Service
Figuring out whether a document requires personal service or allows mail service, and then making sure the proof of service is filled out and filed correctly, is a common place for self-represented filers to lose time. Virdix is built to help:
- Guided questions, so you know which service method applies to each document in your case
- Consistency checks, so names, addresses, and dates match across your proof of service and the documents it covers
- Filing reminders, so a completed proof of service doesn't sit unfiled
- County-specific instructions, tailored to your local Superior Court
We don't replace an attorney for contested or complex matters, but for routine filings, Virdix helps make sure your service paperwork holds up.
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This article is for informational purposes only and does not constitute legal advice. Virdix is a document preparation service, not a law firm, and does not provide legal advice. For advice about your specific situation, consult a licensed California family law attorney.
Sources: California Courts Self-Help Center (selfhelp.courts.ca.gov), Judicial Council of California