Detect. Determine. Register. File.
Full-Stack VAT Automation.

Executive Summary

DeterminedAI is a full-stack VAT/GST automation platform built for cross-border SaaS, marketplaces, and digital businesses. One product covers the full lifecycle: detect, determine, register, file.

• Detect: Stripe-native exposure check and CSV ingest surface every jurisdiction where a seller has crossed a registration threshold, across 60+ nonresident regimes, before a tax authority finds it first.
• Determine: Claude classifies any transaction into 25 supply types with confidence scoring; deterministic engines apply place-of-supply, rates, and ERP tax codes across 103 jurisdictions.
• Register: Guided EU OSS (Non-Union) with Irish Revenue, plus managed BC PST and Quebec QST registrations, including live OTP-relay for Quebec's Specified System.
• File: Automated quarterly EU OSS returns via ROS Digital Certificate, UK MTD VAT real-time submission, Ireland VAT3, New Zealand GST F5, and Singapore GST.
• Free public tools: Multi-country tax-ID validator (VIES, HMRC, Brønnøysund), filing-deadline tracker, and global e-invoicing mandate tracker.

Legacy engines (Avalara, Vertex, Thomson Reuters ONESOURCE) require manual mapping of every SKU to a proprietary tax code, multi-month implementations, and annual contracts in the five-to-six figure range. They sell the engine but leave exposure analysis, registration, and filing to an army of consultants.

DeterminedAI is the only platform that monitors exposure, determines in real time, registers on your behalf, and files automatically, from one product, one contract, one price sheet. Onboarding is hours, not months. The Compliance subscription bundles registration, the engine, monitoring, and all filings at $99 per jurisdiction per month (EU OSS counts as a single jurisdiction covering all 27 EU countries); engine-only access starts free and tops out at $699/mo. No SOWs, no implementation partners.

Why Legacy Tax Engines Fail Modern SaaS

Manual mapping is the bottleneck. Avalara has thousands of AvaTax codes; Vertex has its own taxonomy; ONESOURCE has another. Every SKU must be mapped before a single determination runs. A 500-product catalog across 25 EU countries is a multi-month project before go-live.

Rule engines don't understand context. A keyword matcher sees "software training" and picks one code. It can't distinguish a live instructor-led course (education service, possible reduced rate) from a pre-recorded video (electronically supplied service, standard rate). Wrong assignment, silent miscalculation, every transaction.

They sell determination, not compliance. Legacy engines stop at "what's the rate." Registration in each jurisdiction, return preparation, e-filing: that's all sold separately by their professional services arm or punted to a third-party partner. ViDA, KSeF, FATOORA, MTD: each is a different SOW.

Pricing assumes enterprise. Annual contracts, implementation fees, and per-transaction overage charges scale poorly for early-stage SaaS that just needs to file an EU OSS return on $40k of B2C revenue.

Exposure & Nexus Monitoring

Determination only matters once you know where you owe. For nonresident sellers, the hardest question isn't “what's the rate”: it's “which jurisdictions have I already crossed a registration threshold in, and didn't notice?” Avalara, Vertex, and ONESOURCE assume the customer already knows. DeterminedAI starts a step earlier.

Inputs

• Stripe sync: Connect a restricted API key. We pull Charges, Invoices, and Customer location data (billing address, tax ID, IP geolocation) and reconstruct a per-country revenue and headcount picture.
• CSV upload: For non-Stripe billing stacks (Chargebee, Recurly, Paddle, in-house). Up to 100,000 rows per upload, mapped via a column-picker UI.
• Direct API: POST /v1/exposure/transactions for programmatic ingestion from a data warehouse.

Threshold engine

A version-controlled threshold registry covers 60+ nonresident regimes: EU OSS Non-Union (no threshold), UK (£0 for digital B2C), Norway VOEC (NOK 50,000), Singapore OVR (SGD 100,000 global + SGD 100,000 to Singapore), Japan JCT (JPY 10M), Australia Simplified GST (AUD 75,000), India OIDAR (no threshold), and the long tail of LatAm, EMEA, and APAC digital-services regimes. Each threshold tracks its window (rolling 12-month, calendar year, prior year, or trailing four quarters) and the metric type (gross revenue, taxable revenue, transaction count, or a combination).

Output

A per-jurisdiction status board with four states: safe (under threshold with comfortable margin), approaching (within 20% of threshold), crossed (over threshold, registration required), and overdue (crossed more than 30 days ago without an active registration). Each row links to the relevant Country VAT guide, the registration pack price, and an estimated back-tax exposure if the threshold was crossed in a prior period.

System Architecture

A modular pipeline. AI does what AI does best: understand descriptions. Deterministic engines do what must be exact: rates, place-of-supply, ERP codes.

A second pipeline runs in parallel for exposure analysis (same threshold registry and jurisdiction data, different ingestion path):

The AI never sets tax rates. It classifies what a transaction is; deterministic engines decide how it's taxed. Rates stay auditable and reproducible; classification gains real understanding.

AI-Powered Transaction Classification

Anthropic's Claude classifies transactions into VAT/GST supply types from natural-language descriptions plus context (countries, B2B/B2C, direction). Domain-specific prompting, structured JSON output, confidence scores, and human-in-the-loop approval.

A keyword matcher sees "software" and picks one code. Claude distinguishes:

• SaaS subscription: electronically supplied service
• Perpetual license on USB: goods
• Custom software development: consulting (B2B reverse charge)
• Live-instructor training: education (potential reduced rate)

25 supply types across 7 categories

Confidence scoring & caching

Every response is structured JSON with a 0.0–1.0 confidence score and reasoning. High-confidence classifications auto-approve; medium and low are flagged for review. Once approved, the (product_code → supply_type) mapping is cached. The AI is not called again for that SKU. AI is onboarding acceleration, not runtime cost.

Determination Pipeline

Place of Supply

A deterministic engine maps (seller_country, customer_country, customer_type, supply_type) to the taxing jurisdiction with full rule traceability. Implements EU VAT Directive Arts. 44/45/58, the €10,000 micro-business threshold, B2B reverse charge, TBE rules, destination-based goods, and analogous rules outside the EU. Output feeds OSS reporting directly: one return covers all 27 EU member states.

Rate Lookup

5,100+ rate entries across 103 jurisdictions in version-controlled YAML, sourced from the EY Worldwide VAT, GST and Sales Tax Guide 2026. Indexed by country × supply type × treatment (standard, reduced, zero-rated, exempt, reverse charge). Every rate change is a tracked diff. No opaque vendor release notes.

ERP Tax Code Mapping

Some ERPs ship fixed code vocabularies; others (QuickBooks, D365, SAP) use customer-defined strings that only exist inside each installation. We reflect that reality with a two-tier model and never fabricate codes we can't verify.

Tier 1 ships verified static defaults from vendor sources (NetSuite SuiteTax docs, the XeroAPI/Xero-NetStandard enum, Sage Intacct API examples), live the moment an API key is issued. Tier 2 discovers codes via the vendor API (QuickBooks TaxCode query) or collects them at onboarding via POST /v1/setup/erp-mapping. Until configured, adapters return null with a warning. We will not invent a code the ERP write API will silently reject. A Raw API endpoint returns determinations without ERP formatting for any system without a dedicated adapter.

Managed Registrations & Automated Returns

Determination is table stakes. The work that actually consumes finance teams (getting registered, then filing every quarter) is where DeterminedAI replaces the consulting layer that Avalara and Vertex sell separately.

EU VAT OSS (Non-Union), Irish Revenue

A four-step wizard collects everything Revenue requires (company, contacts, trading history, Verification Code), maps directly to the ROS vatmoss-web form, and tracks status through submission → review → approval → Digital Certificate retrieval. The effective date is calculated automatically (first day of the submission quarter, as Revenue does not backdate), and any pre-OSS exposure is flagged so it can be addressed before the first return.

Once the .p12 Digital Certificate is uploaded, DeterminedAI takes over: quarterly returns are calculated per member state and submitted via ROS automatically. Three secrets (Verification Code, System Password, Certificate passphrase) are encrypted with Fernet keyed to a server-side master key, with append-only audit logging on every reveal.

Canadian provincial registrations

• BC PST (eTaxBC): Self-Serve filing pack and Managed operator-mediated submission. Smart inbox auto-parses Revenue letters and attaches enrolment codes to pending registrations.
• Quebec QST (Specified System): Managed registration with live OTP-relay: forwarding rules capture Revenu Québec's 5-minute verification codes; day-3 and day-7 chasers handle stalled enrolments; day-14 escalation flags revoked forwarding rules.
• CRA Business Number: in-flight; required for federal GST/HST.

Multi-jurisdiction return filing

Every filing produces a PDF draft return and an XLSX workpaper for review before submission. Pricing is flat-fee per filing: not a percentage of liability, not bundled into a six-figure ELA.

Operator console

An admin-only workspace runs the managed-services back office: 8-state registration queue (queued → preparing → awaiting_signature → submitted → awaiting_code → activated/rejected/cancelled), filing submission queue, and a shared inbox that parses authority correspondence and auto-attaches enrolment codes to the right account.

Free Public Tools

No login, no rate limits, no upsell wall. Used as lead generation but genuinely useful in their own right, and not offered by Avalara or Vertex.

• Tax-ID Validator (/tools/validate): Batch VAT/GST/ABN validation across ~20 countries via VIES (EU), HMRC (GB), Brønnøysund (NO) plus regex format checks. CSV upload, downloadable results.
• Filing Deadline Tracker (/tools/deadlines): Searchable VAT/GST filing frequency and due dates by jurisdiction, sourced from primary tax-authority publications.
• E-invoicing Mandate Tracker (/tools/einvoicing): Filterable global compliance status: SdI (IT), KSeF (PL), ZATCA FATOORA (SA), SII (CL), MyDATA (GR), Peppol rollouts, and EU ViDA timelines.
• Stripe Exposure Check (/exposure): Connect a Stripe restricted key, get a per-jurisdiction exposure snapshot from live Charges plus Customer location data. Snapshot persistence is a $29/mo upsell; the check itself is free.

DeterminedAI vs. Avalara, Vertex & Thomson Reuters

Integration & Data Flow

REST API plus first-class CSV/JSON batch uploads (up to 1,000 transactions/upload), webhook-driven sync, and direct Stripe ingest for B2C SaaS.

Onboarding workflow

1. Upload transactions: CSV (descriptions, countries, amounts) or connect Stripe directly. Claude classifies each line with a confidence score.
2. Review & approve: Bulk-approve high-confidence rows; reclassify the rest. Approved mappings are cached.
3. Configure ERP: Tier 1 (NetSuite, Xero UK/AU/NZ/SG, Sage Intacct AU) ships verified defaults. Tier 2 (QuickBooks, D365, SAP) discovers via vendor API or POST /v1/setup/erp-mapping. Raw API for everything else.
4. Add registrations: Declare nexus per jurisdiction. Determinations respect it. Need OSS / BC PST / QC QST? File the managed registration from the same screen.
5. Go live: Point your ERP, billing system, or webhook at /v1/tax/determine.

API request example

API response example

Jurisdiction Coverage

DeterminedAI launches with rate data for 103 jurisdictions across all major economic regions. Each jurisdiction includes rates across all 25 supply types, covering standard rates, reduced rates, zero-rated supplies, and exempt categories.

New jurisdictions are added by authoring rate entries in version-controlled YAML. No code changes required. Source: EY Worldwide VAT, GST and Sales Tax Guide 2026, supplemented by primary tax-authority publications.

Security & Compliance

• Encryption in transit: TLS 1.2+ for all API traffic.
• Encryption at rest: AES-256; ROS credentials (Verification Code, System Password, Digital Certificate passphrase) wrapped with Fernet keyed to DVAT_MASTER_KEY.
• Authentication: Supabase Auth (Google OAuth, magic link) or SHA-256 hashed API keys.
• No model training on customer data: Anthropic zero-retention applies to determinations.
• Audit trail: every determination, every credential reveal, every registration status transition logged to append-only storage.
• GDPR: data processor, SCC Module 2, DPA on request, 30-day access/correction/deletion SLA.
• Row-Level Security on all multi-tenant Postgres tables (Supabase RLS).
• Infrastructure: Vercel (app), Supabase/AWS (Postgres), Anthropic (LLM), Stripe (billing).

Scope & Limitations

In scope today

• AI classification across 25 supply types with confidence scoring and human-in-the-loop review.
• Rate, place-of-supply, and ERP-code determination across 103 VAT/GST jurisdictions.
• ERP adapters for NetSuite SuiteTax, Xero, Sage Intacct (Tier 1) and QuickBooks Online, Dynamics 365, SAP S/4HANA (Tier 2), plus Raw API.
• Managed registrations: EU OSS Non-Union (Irish Revenue), BC PST, Quebec QST with OTP-relay.
• Return filing: EU OSS, UK MTD, Ireland VAT3, NZ GST F5, Singapore GST.
• Tax-ID validation across ~20 countries (VIES, HMRC, Brønnøysund + regex).
• Free public tools: validator, deadline tracker, e-invoicing tracker, Stripe exposure check.
• Stripe-native ingest, webhook sync, async batch (1,000 transactions/upload), audit trail with configurable retention.

Out of scope (current release)

• US state sales tax: a different regime (origin vs. destination, product taxability matrices, state-by-state nexus). Separate product on the roadmap.
• Non-OSS local VAT returns outside the filing list above (e.g. domestic German UStVA, French CA3, Polish JPK_V7), in development.
• E-invoicing & real-time reporting (SdI, KSeF, FATOORA, ViDA): tracked, not yet emitted.
• Customs duties / import VAT calculation on cross-border goods.

Conclusion

Avalara, Vertex, and Thomson Reuters built tax engines for a world where the customer paid consultants to map products and accountants to file returns. DeterminedAI was built for a world where neither budget exists.

Claude is the intelligence layer. Deterministic engines are the precision layer. Managed registrations and automated filings are the compliance layer. One product, three layers, no SOWs.