What SPF handles
Determining the forms
Resolves home and work addresses to taxing jurisdictions and returns the applicable forms, accounting for reciprocal agreements, nexus, local jurisdictions, and lock-in letters.
Guiding the employee
Serves each form as a sequence of questions, branching on the employee’s answers so they only see the questions that apply to them.
Producing the document
Fills and signs the official government PDF, including the penalty of perjury declaration and jurisdiction-required instructional text.
Returning the elections
Hands back the employee’s withholding elections as structured tax parameters your payroll system can consume directly.
SPF does not calculate withholding.SPF establishes what an employee’s withholding elections are. Turning those elections into a dollar amount on a paycheck is the job of your payroll engine, or of the Symmetry Tax Engine if you license it. If you use both, the tax parameter mapping connects them.
Nothing is stored
SPF is a pass-through. It does not retain employee answers, completed forms, or personal data: names, Social Security numbers, and addresses flow from your request to your response and are not kept. Symmetry tracks only which form IDs were completed, as an aggregate usage metric. This is deliberate. Employee PII never rests in Symmetry’s systems, which keeps SPF out of your data-retention and breach-exposure surface entirely. Because you remain the system of record, store the PDF and tax parameters when SPF returns them. See SPF data retention.Next steps
Implementation types
Choose between the API, the Hosted UI, and On-Premise.
Core concepts
The ideas that apply to every SPF integration.
Form coverage
The jurisdictions and form types SPF supports.
Licensing
How licensing and authentication work.

