Kintsugi

Kintsugi is an API-based sales-tax platform for businesses that need to understand where they create tax obligations and turn that insight into managed compliance. It is best suited to companies expanding across US states that want a free monitoring stage before paying for automated registration and returns. Its main limitation is that international coverage and several advanced integration options are reserved for the Premium tier.

Overview

Kintsugi brings sales-tax calculation, nexus monitoring, registration, filing, and remittance into one workflow. The Free plan can monitor global physical and economic nexus, assess risk, flag threshold exposure, and audit historical liability without a subscription or credit card. That makes it useful for finance teams investigating obligations or preparing for expansion, but it is an exposure-management tool rather than a replacement for paid filing services.

Starter is aimed at recurring US compliance. It adds automated registrations, returns, remittance, supported deregistration, refunds, amendments, and exemption-certificate management. Businesses that need a broader international compliance program, premium connectors, or enterprise access controls must move to Premium. Kintsugi is headquartered in San Francisco and was founded in 2022.

Key features

Nexus and liability monitoring

Free tracks physical and economic nexus globally, provides risk assessment and threshold alerts, and supports exposure and historical-liability audits. These capabilities help a business identify where registration may be required before it commits to filing costs. AI-powered product categorization, CSV transaction imports, and no-code integrations give smaller teams practical ways to assemble transaction data without building a full integration first.

US registration and filing

Starter automates US sales-tax registrations, filings, and remittance. Auto-file, auto-register, and deregistration are supported where applicable, while refund and amendment handling addresses changes after a return has been prepared. Exemption-certificate management is included, which matters for businesses handling non-taxable customers or transactions. Sales-tax calculation and API access are part of Kintsugi's core positioning.

Premium compliance and access

Premium extends compliance across the US, Canada, EU, UK, and more than 100 countries. It adds real-time calculation through premium connectors, voluntary-disclosure-agreement back-filing options, advanced exemption-certificate management, API, SDK, and SSO access, plus SLA-backed premium support. Those additions are relevant to larger or multinational teams, but the plan's price is custom, so its cost must be weighed against the value of the broader coverage and service commitment.

Pricing

Free

The Free plan costs $0.00 USD and is not billed; no credit card is required. It includes global nexus monitoring, historical-liability auditing, risk and threshold alerts, AI product categorization, CSV imports, and no-code integrations. It suits businesses still determining exposure or needing a low-commitment starting point. It does not provide the automated US registration, filing, and remittance workflow found in Starter.

Starter

Starter costs $75 a month. Each filing or registration is billed as one action after the billing period ends, so the headline subscription is not the complete cost model for businesses with frequent filings or registrations. It is the practical tier for companies ready to automate US sales-tax operations, especially those that need filing, remittance, refunds, amendments, and certificate management rather than monitoring alone.

Premium

Premium has custom pricing. It is designed for multi-country compliance and organizations that need premium connectors, VDA back-filing, advanced certificate controls, SDK and SSO access, and SLA-backed support. Teams that only need US filing may find its expanded scope unnecessary.

Platforms

Kintsugi is offered as an API platform. That orientation favors businesses integrating tax workflows into existing systems rather than buyers seeking a primarily standalone web application.

Who it's for

Kintsugi fits growing businesses that sell across US states and need a path from nexus discovery to automated compliance. Free is appropriate for early exposure analysis; Starter suits teams ready to register, file, and remit; Premium is aimed at multinational or enterprise operations requiring broader jurisdictions and controlled integrations. It is less suitable when a company needs only a simple web-based filing service or wants predictable pricing without action-based charges.

Pros and cons

Pros

• Useful free entry point: Nexus monitoring, liability audits, alerts, imports, and no-code integrations are available without payment or a credit card.
• Clear path to US automation: Starter connects registration with filing and remittance, and also covers refunds, amendments, and supported deregistration.
• Enterprise expansion: Premium adds multi-country coverage, SDK and SSO access, premium connectors, and SLA-backed support.

Cons

• Action-based Starter billing: Every filing or registration counts as a billed action after the billing period, which can make costs less predictable.
• Advanced capabilities are tiered: International compliance, real-time premium connectors, SDK, SSO, and advanced certificate management require Premium custom pricing.
• API-first delivery: Organizations wanting a primarily web-based workflow may find the platform orientation less natural.

Alternatives

Yonda Tax is worth considering when free nexus determination and worldwide liability calculations should be paired with tax advice and support, with web access as well as an API.

Zamp suits teams seeking a free 30-day sandbox for tax-exposure clarity before moving to audit-ready US compliance.

ShipVAT is a better fit when a free plan with 100 API calls per month, web access, and a free trial matches the required usage pattern.

CCH SureTax offers technology-only, file-and-remit, and fully outsourced approaches for buyers comparing service scope.

Taxolio fits web users who prefer managed compliance priced per state, including a two-state plan at $99 a month.

Taxually is an option for businesses buying individual tax-authority payments or yearly reporting services.

Complyt is another paid API and web alternative.

Vertex e-Invoicing is aimed at e-invoicing workflows, with coverage varying by country and VAT periodic reporting offered as an add-on.

Verdict

Choose Kintsugi if you need an API-centered route from sales-tax exposure monitoring to automated US registration, filing, and remittance. The Free plan is unusually useful for establishing nexus and historical liability before committing, while Starter provides the operational workflow most expanding US businesses need. Look elsewhere if you require broad international compliance without a custom-priced tier, or if action-based charges and an API-first platform do not fit your budgeting or operating model.