Consulting and programming services are not subject to sales tax in Pennsylvania as far as I understand, however you're in a better position to judge than I am.
According to the Pennsylvania Department of Revenue website, tangible goods, services on those goods, and specific other services require sales tax.
Extract from How do I know which items or services are subject to Pennsylvania Sales Tax? (emphasis mine)
Generally, the purchase of an item by the ultimate consumer is subject
to sales tax. Likewise, services performed on taxable items are
subject to sales tax, along with some specifically designated services
set forth in the law.
The list of specifically designated services are mentioned on the page Is there a list of services subject to PA sales tax?:
Following is a list of taxable services in Pennsylvania.
- Printing or imprinting of tangible personal property of another.
- Washing, cleaning, waxing, polishing or lubricating of motor vehicles.
- Inspecting motor vehicles as required by law.
- Repairing, altering, mending, pressing, fitting, dyeing, laundering, dry-cleaning or cleaning tangible personal property other than wearing apparel or shoes.
- Applying or installing tangible personal property as a repair or replacement part of other tangible personal property.
- Lobbying services.
- Adjustment services, collection services or credit reporting services.
- Secretarial or editing services.
- Disinfecting or pest control services.
- Building maintenance or cleaning services.
- Employment agency services or help supply services.
- Lawn care services.
- Self-storage services.
- Mobile telecommunications services.
- Premium cable and video programming services including streaming of videos.
- Non-residential electric, steam, and gas services.
- Intrastate and interstate telecommunications services billed to PA service addresses except subscriber line charges and basic local residential phone service for residential use and payphone service.
Since consulting and programming aren't on this list, my understanding is that you're in the clear, however I don't have a complete understanding of the services you offer. You're in a better position to judge if your business falls into one of the above categories.