Zamp Developer Platform
Build rooftop-accurate sales tax into your product
Calculate tax in real time, track economic nexus, and post transactions for filing — through the Zamp APIs or a fully managed platform integration.
Quickstart
Go from zero to your first tax calculation in four steps.Get a trial token
Authenticate
Authorization header on every request. See Authentication.Run your first calculation
POST /calculations to get the tax due plus a full jurisdiction breakdown in real time.Post the transaction
POST /transactions. This is the core calculate-then-post workflow behind every Zamp integration.Two ways to build
Choose your path
Build with the API
Full control over calculation, transactions, and filing — natively in your own UI, with no third-party plugins or connectors.
Explore the API →Use a platform integration
Connect through Shopify, NetSuite, BigCommerce, QuickBooks and more — built and maintained by Zamp, no code required.
Browse integrations →What you can build
Capabilities
Real-time calculation
Rooftop-accurate tax on every transaction, with a full jurisdiction breakdown.
Transactions for filing
Persist sales, refunds, and credit memos so Zamp can file accurately.
Address validation
Validate and normalize addresses to improve calculation accuracy.
Nexus tracking
Monitor economic nexus across states as your sales grow.
Exemptions
Handle resale and entity-based exemptions on transactions and line items.
Managed filing
Access registrations and filing history, with returns handled by Zamp.