Everything you need to ship US sales tax on TaxMySaaS.
A practical map through onboarding, the TaxJar-compatible API, and the web portal. Whether you are wiring up your first checkout call or handing off nexus monitoring to finance, the guides below walk through the exact path step by step.
What this documentation covers
TaxMySaaS sits between your billing system and US state revenue departments. The product gives you three surfaces — an API your code calls, a web portal your finance team works from, and webhooks that notify you when state thresholds need attention. These docs cover all three, plus the things that connect them: API keys, the transaction ledger, projections, and the nexus model.
TaxJar-compatible endpoints
Drop-in API surface for rates, tax calculation, and transaction capture.
Idempotent transaction ledger
Record taxable sales using external_id so retries do not duplicate rows.
Economic nexus monitoring
Trailing twelve-month revenue and transaction thresholds per state.
Projections and alerts
See when states will cross thresholds and get webhooks before they do.
Team-based multi-tenancy
Invite teammates, scope API keys per environment, manage billing.
Predictable usage limits
Per-second rate limits and monthly transaction allowances.
Core concepts
Team
The top-level tenant. Every API key, transaction, nexus record, and webhook is scoped to a single team. Users can belong to multiple teams.
API key
A long-lived secret that authenticates the API on behalf of one team. Keys are tagged live or test so you can exercise the API in staging without affecting nexus.
Transaction
A recorded taxable sale or refund tied to a customer state. Transactions drive both the audit ledger and the nexus rollups. external_id makes inserts idempotent.
Nexus status
A per-state classification of trailing twelve-month revenue and transaction counts: monitoring, approaching, exceeded, or registered.
Projection
A forward estimate of when a state will cross its threshold, based on recent monthly run-rate. Used in the portal and surfaced via the projections API.
Webhook
An HTTPS callback fired when a transaction is recorded or a state nexus status worsens. Signed with a per-endpoint secret.
Start with onboarding.
Most teams are calling the API and seeing transactions in the portal within an hour. The onboarding guide walks through it end to end.