Look up sales tax rates inside your workflow.
Use API services to support destination-based rate lookup, checkout-adjacent tax workflows, and internal quoting tools where sales tax needs to be calculated before filing starts.
Sales Tax API Services
Sales tax APIs for merchant workflows.
AtomicTax offers API services for teams that need sales tax rate lookup, calculation support, ecommerce integrations, source data handoff, and filing-ready workflows.
Connect ecommerce and billing systems.
AtomicTax API services can help teams move order, customer, transaction, refund, and tax data from storefronts, billing apps, or internal tools into cleaner sales tax operations.
Turn API data into filing-ready records.
API work is most useful when the data can flow into nexus review, registration decisions, filing packet preparation, approval, and confirmation storage.
API Use Cases
Use AtomicTax when sales tax logic needs to live inside your product or operations stack.
- Rate lookup for checkout, quoting, invoicing, or internal order tools
- Sales tax calculation workflows for ecommerce, SaaS, and marketplace data
- API handoff from custom carts, ERP systems, billing platforms, or data warehouses
- Clean transaction exports that support filing packets and state-level review
- Developer-supported integrations where off-the-shelf connectors are not enough
Developer-ready
Need a sales tax API service?
AtomicTax can support API-led sales tax workflows for merchants and platforms that need calculation, integration, reporting, and filing operations to connect cleanly.
How It Fits
API first, filing aware.
Many sales tax APIs stop at the transaction. AtomicTax is built around the downstream workflow too: source data quality, state exposure, registration status, filing cadence, review, and proof of filing.
- Rate lookup and calculation support
- Transaction and tax data normalization
- Marketplace versus direct-channel separation
- Filing packet and confirmation workflow handoff
Example flow
POST /sales-tax/rates
{
"ship_to": "Austin, TX",
"amount": 149.00,
"channel": "custom_checkout"
}Use the API layer to support tax decisions, then keep the same source data organized for filing review.