> ## Documentation Index
> Fetch the complete documentation index at: https://docs-test.symmetry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction to Symmetry Payroll Forms

> What SPF is, what it does, and how to find your starting point.

Symmetry Payroll Forms (SPF) automates the employee withholding form process at the federal, state, and local level. Using an employee's home and work locations, SPF determines which forms are required, guides the employee through completing them, and returns the completed PDF and tax parameters to your system.

SPF supports over 130 online withholding forms for the US and Canada, including all resident, nonresident, military spouse, and Canadian TD1 forms. The full list of supported forms and tax parameter outputs is available in the [SPF Catalog](/spf/references/2026-tax-parameter-catalog-and-schema), updated with each release.

## How SPF is delivered

SPF is available in three implementation types. Each delivers the same compliant forms — the difference is in how much control you have over deployment, UI, and infrastructure.

<CardGroup cols={3}>
  <Card title="API" icon="code" href="/spf/getting-started/spf-api-quickstart">
    Call SPF's endpoints from your own employee-facing UI to handle form determination, question flows, and PDF generation. Best for teams who want full control over the user experience and branding.
  </Card>

  <Card title="Hosted" icon="browser" href="/spf/getting-started/spf-hosted-quickstart">
    Symmetry hosts and maintains the UI for you — embed it in your application or link out to it directly. Launch without building a forms UI yourself. Best for teams who want to get up and running quickly with minimal front-end build work.
  </Card>

  <Card title="On-Premise" icon="server" href="/spf/getting-started/spf-on-premise-quickstart">
    Run the same hosted UI on your own servers. Symmetry delivers compliant form updates for you to roll out on your own schedule. Best for teams that need forms processing to stay inside their own infrastructure.
  </Card>
</CardGroup>

## Where to go next

<CardGroup cols={2}>
  <Card title="API Quickstart" icon="bolt" href="/spf/getting-started/spf-api-quickstart">
    Get up and running with the SPF API.
  </Card>

  <Card title="Hosted Quickstart" icon="bolt" href="/spf/getting-started/spf-hosted-quickstart">
    Embed SPF using the Hosted solution.
  </Card>

  <Card title="On-Premise Quickstart" icon="bolt" href="/spf/getting-started/spf-on-premise-quickstart">
    Install and configure SPF On-Premise.
  </Card>

  <Card title="Release Notes" icon="list" href="/spf/release-notes/spf-2026-r6-release-notes-29-may-2026">
    See what changed in the latest release.
  </Card>

  <Card title="SPF Catalog & Schema" icon="table" href="/spf/references/2026-tax-parameter-catalog-and-schema">
    Browse supported forms, their tax parameter outputs, and the SPF schema.
  </Card>
</CardGroup>