Symmetry Location Service (SLS)

For US SPF Implementations Only

SPF utilizes the Symmetry Location Service (SLS) to determine the suggested forms an employee should complete based on the employee’s resident and work addresses.


SLS translates a physical address into a set of geocoordinates (latitude and longitude) that are used to determine which withholding forms may be applicable to an employee. Additionally, SLS also provides local jurisdiction data including PSD codes, EIT rates, and more based on the employees work and home location. The data returned from SLS is used within some forms based on the jurisdictions where the coordinates may fall.

The webservice does four things:

  1. Compares the address entered to USPS data and normalizes it
  2. Translates normalized address into geocoordinates
  3. Compares location's geocoordinates against taxing jurisdiction shapefiles
  4. Returns withholding forms applicable to taxing jurisdictions

The SLS configuration is set within the "webservice" element of the SPF Registration.

Current clients can log into the Symmetry Client Support Center to see additional "webservice" details.

Postback Address Result Codes

Upon successful completion of a form using Postback, clients will receive a list of address normalization and geocoding result codes for a given location ("addressResultCodes"). These result codes do not always indicate a geocoding failure has occurred. These messages inform clients of the status of the address normalization process, and any possible changes that occur.

Current clients can log into the Symmetry Client Support Center to see postback examples and learn about additional functionality available in SPF related to address verification.

Jump to top