How to Get an EIN for Your Mobile Developer Business in Illinois (2026)

As a mobile developer in Illinois, whether you're building apps for clients, selling your own creations on the app store, or running a full-fledged mobile development agency, an Employer Identification Number (EIN) is crucial. Think of it as your business's Social Security number. This guide walks you through obtaining an EIN for your mobile developer business in Illinois in 2026.

What is an EIN?

An EIN is a unique nine-digit tax identification number assigned by the IRS to business entities operating in the United States. It's used to identify your business for tax purposes and is essential for various business activities, like opening a business bank account or hiring employees. Even if you're a single-member LLC in Illinois, you might need an EIN.

How to Apply for an EIN

  1. Determine Your Eligibility: Ensure your mobile development business entity (LLC, corporation, etc.) is properly registered with the Illinois Secretary of State. You must have a legally formed entity to apply for an EIN.
  2. Choose Your Responsible Party: The 'responsible party' is the individual who controls, manages, or directs the entity and the disposition of its funds and assets. This is typically the owner or a high-ranking officer in your mobile development business.
  3. Complete the IRS Form SS-4: You can download Form SS-4 from the IRS website. Fill it out accurately, providing information about your Illinois mobile development business, such as its legal name, address, and the reason for applying for the EIN.
  4. Submit Your Application: You can apply for an EIN online through the IRS website, by fax, or by mail. The online application is the fastest method and is generally recommended.
  5. Receive Your EIN: If you apply online, you'll typically receive your EIN immediately. If you apply by fax or mail, it may take several weeks.
  6. Verify Your EIN: After receiving your EIN, verify its accuracy on the IRS website. This helps prevent potential issues with tax filings or other business transactions.

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