Authenticate with your TaxJar API token as 'Token token=<API_KEY>'
GET https://api.taxjar.com/v2/nexus/regions to retrieve the full list of nexus states/regions currently on file for your account
Review the returned array for states where you've crossed economic nexus thresholds but haven't yet registered
POST to https://api.taxjar.com/v2/nexus/addresses with 'country', 'state', 'city', 'zip', and 'street' to add a new physical nexus location
DELETE https://api.taxjar.com/v2/nexus/addresses/:id when you close a location or are no longer required to collect in that jurisdiction
Known gotchas
The nexus/regions endpoint returns states where TaxJar has been told you have nexus; it does not automatically detect when you cross an economic nexus threshold — that monitoring must be done separately
Adding a nexus address takes effect immediately for subsequent tax calculation calls; ensure your registration with the state taxing authority is completed before collecting tax
Some states have both transaction-count and revenue thresholds for economic nexus; crossing only one may still trigger an obligation in certain states
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp