FL-335: The Paper Trail After the Envelope
FL-335 is California's proof of service by mail. It is the boring page that tells the court your packet actually left your hands and reached the address the rules require. Custody fights live in facts and hearings, but procedure still wins when service is sloppy. If you are building a request for order on custody (FL-300), treat FL-335 as part of the same filing chain, not an afterthought.
Exact documents in the mailed packet, matching what you filed.
Address source, mail date, and server identity if a non-party mailed.
Proof of service filed so clerks can connect notice to your motion.
What people get wrong
- Assuming "I mailed something" without matching versions
- Using an old address from memory instead of the last filing
- Forgetting who is allowed to mail under your rules
- Treating service as optional if you already emailed
What strong proof looks like
- Copy of the served packet stapled to your notes
- Date and method written the same day as mailing
- Address line tied to a rule or filed document
- Calm, short facts on the form itself
| Slip | What breaks |
|---|---|
| Wrong packet version served | Hearing timelines and responses do not line up |
| Missing non-party mailer details | Clerk rejects or opponent challenges notice |
| Late-filed proof | Your motion looks procedurally unfinished |
Related guides
More California forms
General support (not California-specific)
Official FL-335
https://selfhelp.courts.ca.gov/jcc-form/FL-335Service questions
What does FL-335 actually prove?
That the papers you mailed were the correct documents, went to the right address, and were mailed on a date you can swear to, with a non-party mailer when rules require it.
Why do parents underestimate this step?
Because the motion feels done once it is drafted. Courts still need a clean proof of service to start clocks and show the other side had fair notice. Missing or vague proof can stall the whole custody or support request.
How does FL-335 relate to FL-300?
FL-300 is the request for order you want heard. FL-335 is the mailing receipt for the packet you served. They are different forms with different jobs; you file both when mail service applies.
Related financial disclosure in California family practice: FL-150 income and expense declaration.
MyCustodyCoach is not a law firm. Court rules, fees, and form versions change by county; confirm what applies to your case with official court resources or counsel you hire.
Last reviewed: 2026-06-03