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Onboarding SDK: Simplified Tax Certification

October 15th, 2026

Release Details

Release Date: October 15, 2026

Release Type

Informational – Optional action from platforms

Summary

The zerohash Onboarding SDK now collects the U.S. tax certification during onboarding. Customers enter one tax ID with their address, review their information, and confirm one checkbox. There is no separate W-9 or W-8BEN form and no typed signature. zerohash then creates the W-9 or W-8BEN and records the signature.

This release also includes:

  • Onboarding flows. The new optional onboardingFlow parameter on openModal selects the flow:
    • full_with_tax (default): full onboarding with the tax certification.
    • full_without_tax: full onboarding without the tax certification.
    • tax_only: the tax certification only, for customers who are already onboarded. No new KYC is run.
  • Customers subject to backup withholding can complete onboarding. zerohash does not reject them.

zerohash turns on the new flows per platform. Contact your zerohash representative to turn them on. Platforms that are not turned on, and customers who onboard through zerohash europe (EU/EEA), keep the current experience.

Action Required

None for the default experience. When the new flows are on for your platform, new customers get the simplified tax certification with no code changes.

Optional:

  1. To choose a flow on the web, upgrade to zh-web-sdk 3.12.0 or later and pass onboardingFlow. Mobile WebView integrations cannot send onboardingFlow yet and get full_with_tax.
import { AppIdentifier, OnboardingFlow } from 'zh-web-sdk';

sdk.openModal({
  appIdentifier: AppIdentifier.ONBOARDING,
  jwt: '<JWT>',
  onboardingFlow: OnboardingFlow.FULL_WITHOUT_TAX, // Optional: defaults to OnboardingFlow.FULL_WITH_TAX
});
  1. To collect the tax certification from existing customers, request a client access token with the customer's participant_code and the update-participant permission. Then open the Onboarding SDK with onboardingFlow: OnboardingFlow.TAX_ONLY. Platforms on vendor reliance need zerohash approval to use tax_only.

What stays the same

  • Existing openModal calls, events and token requests. If you omit onboardingFlow, the SDK uses the default flow.
  • EU/EEA onboarding.

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