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When an unemployment claim is filed by an individual, the employer is mailed an OES-617 "Notice of Application for Unemployment Compensation". Additionally, employers may receive an electronic notification and review the details to the notice through OESC’s Employer Portal.

Employers may respond or protest this notice by using our paper response form available below or electronically through SIDES Web Services or E-Response, which is available through OESC's Employer Portal.

To utilize the OESC Employer Portal, employers must first log on to their EZ Tax Express account to set up and link their EZ Tax account to the new Employer Portal.

If using the Employer Response Form, submit via mail to Unemployment Service Center, PO Box 52006, Oklahoma City, OK 73152 or fax to 405-962-7524.

Additionally, employers have the option of pre-filing a response as soon as an employee is separated from employment. To learn more, view this helpful guide or call our employer hotline at 405-552-6799.

What is SIDES?

Developed through a strategic partnership between the U.S. Department of Labor (USDOL) and state UI agencies, the National Association of State Workforce Agencies’ (NASWA) State Information Data Exchange System (SIDES) and SIDES E-Response offer employers and TPAs – free of charge – a secure, electronic and nationally-standardized format in which they can easily respond to UI information requests, attach documentation when needed and receive a date-stamped confirmation of receipt.

View a helpful SIDES E-Response User Guide

Watch a short video detailing the different SIDES options

Watch a short video introducing the benefits to SIDES E-Response

SIDES Web Services vs. SIDES E-Response

SIDES Web Services

  • Ideal for large employers with numerous separations.
  • Provides automated data exchange between employer's IT systems and state UI agency
    • Requires IT work from employer to integrate, which may involve expenses the employer is responsible for.
  • Must have Oklahoma UI Tax Account number.
  • Must contact OESC at to set up.

SIDES E-Response

  • Ideal for small to medium sized employers with few separations.
  • Available through OESC's Employer Portal.
  • Must have Oklahoma UI Tax Account number.
  • Employers eligible for E-Response will be notified in an OES-617 "Notice of Application for Unemployment Compensation".

For questions or assistance with SIDES, contact OESC at

Mass Claims

In some cases, employers may file a mass claim which will establish the initial claim on behalf of the claimant. Claimants will be required to file their own weekly certifications, but will not be required to register and search for work. To file a mass claim, employers must meet the certain requirements:

  • laying off 25 or more employees,
  • have a return to work date, 
  • return to work date must be eight weeks or less away

Detailed instructions for submitting a mass claim can be viewed via the button below. For questions about mass claims call 405-557-7244 or email

Appealing A Decision

Typically, protests will be sufficient to resolve disputes; however, there may be cases where an employer disagrees with a decision on a protest and wishes to file an appeal. Any appeals rights will be included in notices sent by OESC. Additional information regarding the appeals process can be found in our Appeals Information and Guide document.