Contract manufacturer (CM / EMS)
also: CM · EMS · electronics manufacturing services
A company that builds your product to your design and specifications; EMS providers specialize in electronics assembly, often with box build and test.
A CM builds what you specify. You own the design, BOM and test requirements; they buy parts (or receive parts you supply), assemble, test, pack and ship. Electronics manufacturing services (EMS) providers focus on circuit board assembly and often offer complete product ("box build") assembly. Choosing a CM means choosing a long-term partner whose capabilities, typical volumes and engineering support fit your stage.
Contract points that matter: who owns tooling and fixtures, how component and labor pricing works, who carries excess and obsolete inventory, quality requirements and acceptance criteria, the change process, IP protection, and terms for moving production elsewhere.
Where it bites: a CM much larger than you may deprioritize your builds; one that is too small may lack process control. A CM builds exactly what the documentation says, so gaps in drawings, BOM or test specifications turn into defects.
Founder takeaway
Choose a CM whose typical volumes match yours, and complete your documentation package (BOM, drawings, test specs, acceptance criteria) before asking for quotes.
sources
engineer review pending