ATS Assessor Treasurer Software

API

Freedom report

Two barsScore 6.3

  • Free tierA free tier is on its own pricing page
  • Open codeNo open-source code on record
  • Runs widely0 of 6 device platforms
  • DocumentedPlans, terms and facts published

ATS Assessor Treasurer Software is a property tax application for calculating and collecting taxes. Developed by Kitsap County, Washington, it manages assessments and levies for real and personal property, including new construction, destroyed property, bankruptcies, foreclosures, and LIDs. Counties can set up regular payment plans and advance payment plans, configure accounting, and connect the system with their existing accounting software. They can also choose whether to assign late fees and NSF payments, then use flexible queries to work with tax data. The Personal Property Online module provides a public-facing website where business owners can update their personal property information. ATS has a general-purpose RESTful API, and its user interface accesses data through that API. It works with Kitsap County’s MS SQL database without modifications; using other Entity Framework-supported databases requires a modification change. ATS is described as open source and freely available, while Velosys offers counties deployment assistance, customization, training, and consultation. ATS remains in development by Kitsap County, which is considering making the project available to other counties. The listed plan is 0.00 USD per free.

Who it is for

ATS is intended for counties managing property tax assessments, levies, payments, and accounting. Its public property information module may suit counties that want business owners to update personal property details online.

What is good

  • Manages real and personal property assessments and levies.
  • Supports payment plans and advance payment plans.
  • Business owners can update details through a public module.
  • RESTful API serves both general access and the user interface.
  • Described as open source and freely available.

What to know first

  • Other Entity Framework-supported databases require a modification change.
  • County deployment and customization services have no shown prices.

Verdict

ATS may suit counties seeking a customizable property tax system with assessment, payment, accounting, and public update capabilities. Its free plan and RESTful API are central reasons to consider it; counties using another supported database should account for the required modification change.

Get started with ATS Assessor Treasurer Software

  1. Visit the ATS website.
  2. Review the free ATS plan.
  3. Contact Velosys about deployment assistance, customization, training, or consultation.

Questions about ATS Assessor Treasurer Software

How much does ATS cost?

The ATS plan is listed at 0.00 USD per free. Velosys offers implementation services, but their prices are not shown.

Is ATS open source?

ATS is described as open source and freely available. Kitsap County is considering making the project available to other counties.

What can ATS manage?

It manages property assessments and levies, payment plans, accounting configuration, late fees, NSF payments, and flexible queries.

Does ATS provide an API?

Yes. ATS has a general-purpose RESTful API, and its user interface accesses data through that API.

Which databases can ATS use?

It works with Kitsap County’s MS SQL database without modifications. Other Entity Framework-supported databases can be used with a modification change.

Who developed ATS?

ATS is presented as developed by Kitsap County, Washington. Velosys offers counties deployment assistance and related services.

ATS Assessor Treasurer Software plans and pricing

All plans
ATS Free Open source; customization, deployment, training, and consultation are available services, with no service prices shown velosys.com · 5 Oct 2026

Compared on property tax software

Free plan
Yes
Tax calculation
Yes
Assessment tools
Yes
API access
Yes

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