TL;DR
Define the format and closure in the brief, test guarded zips and snap strength on a sample, then fix measurement points and pack format before the order is placed.
What a onesie order actually covers
The word onesie describes several garments. A footed fleece suit with a hood, a footless jersey all-in-one, a snap front baby bodysuit and a novelty animal suit are all sold under the name, yet each has a different pattern, cost base and compliance route. Settle which product you are buying before you ask for a quotation.
Draw the format in the brief: footed or footless, hood or collar, front zip or snap placket, long or short sleeve. This single paragraph removes most of the misquotes that appear at the sample stage. The Christmas onesie series is a place to start shortlisting styles by item number.
Related on this site: Onesie OEM production · OEM and ODM production categories
Closures: zips, snaps and chin guards
A front zip on a one-piece garment ends near the wearer's chin, so the puller needs a guard or a garage that covers it when the zip is closed. Test the guard on a wearer turning their head, not only on a flat table.
Snap plackets suit baby sizes because they open fully. Ask for the snap pull strength and confirm the reinforcement behind each snap, since a snap that tears the knit when opened becomes a return in the first week.
Small parts and fabric checks
For children's sizes, attached parts such as eyes, pom poms and zip pulls must resist a pull test, and the destination market decides which standard applies. In the United States, the Children's Product Certificate process sets out the testing and documentation route, and the CPSC clothing guidance covers apparel questions including flammability.
Adult novelty suits are not exempt from the commercial version of the same question: a pom pom that sheds inside the bag reads as a fault to the buyer even when the garment itself is intact. Ask for the attachment method and test a sample by hand.
Fabric weight and handle
Weight in grams per square metre tells you more than a fabric name. A heavier fleece reads as a warm suit, a lighter jersey reads as a costume base layer, and the same print looks different on each. Ask for the weight of the fabric actually used in the sample rather than the nominal weight of the quality.
Handle matters as much as weight. Brushed back fleece feels soft but pills at the cuff, while a smooth jersey stays clean but feels thin. Request a wash test and check pilling, colour loss and stitch distortion before approving.
Sizing by height, not by label
All-in-one garments are usually bought by height for children and by chest and inseam for adults. Publish the measurement points you used and keep the same points across the size run, otherwise a size that fits in one fabric will not fit in another.
Allow for the garment being worn over something. A suit cut to body measurement with no ease will pull at the shoulders when a child sits down, and the seat seam takes the strain first.
Printing, embroidery and packing
Print placement on a one-piece has to account for the centre front seam and the curve of the chest. Ask for a placement diagram with distances from the neck seam and the side seam, and check the print on a filled sample rather than flat on a table.
Packing decides how the garment reaches the shelf. Confirm whether it ships flat folded, on a hanger or in a polybag, and set the carton ratio by size so the retailer can open one carton without re-sorting.
- Format: footed or footless, hood or collar
- Closure type with guarded zip or tested snaps
- Small parts tested for the destination market
- Fabric weight and wash test results on file
- Measurement points consistent across the size run
- Print placement diagram approved on a filled sample
- Pack format and carton ratio agreed
- Approved sample retained with the written record
Related on this site: Request a onesie quote