Register a state employer

Last updated Jun 14, 2026

Withholding and unemployment-insurance registration when hiring across state lines.

Trigger

You're hiring an employee in a state where the entity is not yet a registered employer.

Call sequence

1. Open registrations

POST /v1/state_registrations  { entity, state, kinds: ['withholding','sui'] }

2. Wait for completion.

// state_registration.opened

Idempotency

Idempotent on `(entity, state, kind)`.

Webhooks

Errors

Handing account numbers to the payroll provider

Once the state issues account numbers, read the state_account_number field on the StateRegistration resource and provide it to the payroll provider (Gusto, Rippling, Justworks) as part of their state-setup flow. They use it as the remittance destination for state withholding and SUI deposits.

Recurring obligations on the calendar

The state employer registration auto-rolls recurring obligations onto the Compliance view:

• Withholding deposits (cadence varies by state and wage volume — semi-weekly, monthly, or quarterly)
• Quarterly state withholding return
• Quarterly SUI return
• Annual reconciliation

Matter doesn't file these — the payroll provider does — but the calendar entries serve as audit-trail anchors and remind the founder to confirm the payroll provider is in good standing each quarter.

When to register in additional states

Register in a state when any of the following becomes true:

• A W-2 employee's primary work location is in that state.
• An employee with a primary work location elsewhere works more than the state's threshold of days/year in that state (varies by state; CA is particularly aggressive — typically register if any employee works >2 days/month).
• A board member receives compensation while resident in that state.

The decision is per-employee and per-state; when uncertain, register — the cost of an unregistered hire-in-state surfaces later as back taxes and penalties.

Other state-registration kinds

The same endpoint serves three other registration kinds:

See the Compliance landing page for the full state-registration model.