# Sales tax and VAT calculation APIs for AI agents

> 5 tax calculation & compliance listings ranked by the Anchor benchmark. Leader Avalara AvaTax (B). Services that calculate sales tax, VAT and GST for a transaction, record it for reporting and handle registrations, exemptions and filing. Compared on calculation coverage by country and US state, the transaction API, filing and price per call.

- Canonical: https://www.anchorterminal.com/categories/tax
- Markdown: https://www.anchorterminal.com/categories/tax.md (~1,950 tokens)
- Slim: https://www.anchorterminal.com/categories/tax.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/categories/tax.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

Services that calculate sales tax, VAT and GST for a transaction, record it for reporting and handle registrations, exemptions and filing. Compared on calculation coverage by country and US state, the transaction API, filing and price per call.

- Tools ranked: 5 · agent-ready (BB or better): 0 · accept x402: 0 · hosted endpoints: 5 · desk reviews by the panel: 0
- JSON: https://www.anchorterminal.com/api/v1/tools.json (list) · https://www.anchorterminal.com/api/v1/rankings.json (ranked) · https://www.anchorterminal.com/api/v1/x402.json (payable) · https://www.anchorterminal.com/api/v1/capabilities.json (by capability)
- Grades run AA, A, BB, B, C, D, E, F · methodology: https://www.anchorterminal.com/benchmark/

- Capabilities in this category: tax.calculate, tax.transactions, tax.filing, tax.exemptions, tax.invoicing
- https://letme.dev/tax.calculate picks the top-graded tool in this list and says how to call it direct; calling through letme comes later (https://www.anchorterminal.com/letme/index.md)

## Ranking

| # | Tool | Vendor | Kind | Category | Grade | Score | Confidence | x402 | Auth | Where | Reviews | Page |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 162 | Avalara AvaTax | Avalara, Inc. | HTTP API | Tax | B | 68.8 | medium | no | OAuth or key | hosted | none | https://www.anchorterminal.com/tools/avalara.md |
| 321 | Anrok | Anrok, Inc. | HTTP API | Tax | C | 61.6 | medium | no | OAuth or key | hosted | none | https://www.anchorterminal.com/tools/anrok.md |
| 377 | Quaderno | Recrea Systems, SL | HTTP API | Tax | C | 59.5 | medium | no | OAuth or key | hosted | none | https://www.anchorterminal.com/tools/quaderno.md |
| 417 | TaxJar | TaxJar (Stripe) | HTTP API | Tax | C | 57.6 | medium | no | API key | hosted | none | https://www.anchorterminal.com/tools/taxjar.md |
| 464 | Vertex O Series | Vertex, Inc. | HTTP API | Tax | C | 54.7 | medium | no | OAuth | hosted | none | https://www.anchorterminal.com/tools/vertex-tax.md |

Scores are from public evidence against the published checklist (https://www.anchorterminal.com/benchmark/), with Performance and Task success pending. p95 latency and context cost come from our probes, which haven't run yet.

## Summaries

### 162. Avalara AvaTax, B (68.8)

Avalara AvaTax calculates sales tax, VAT and GST for a transaction and records it for reporting. Agents reach it through the AvaTax REST v2 API or a hosted MCP server, with separate Avalara products for returns, exemption certificates and e-invoicing. The REST API has a public Swagger file with 491 operations, a Markdown page per endpoint and a 90-day trial with no card. Production rate limits and prices per transaction are not published, the API patch notes stop at April 2023, and the tax calculation service was degraded for about 23 hours on 5 and 6 October 2026.

- Page: https://www.anchorterminal.com/tools/avalara · Markdown: https://www.anchorterminal.com/tools/avalara.md · JSON: https://www.anchorterminal.com/api/v1/tools/avalara.json
- Capabilities: tax.calculate, tax.transactions, tax.exemptions, tax.filing, tax.invoicing · endpoint: `https://rest.avatax.com/api/v2`

### 321. Anrok, C (61.6)

Anrok is a hosted sales tax, VAT and GST compliance platform for software and ecommerce sellers. Its API calculates tax and records transactions, and Anrok registers, files and remits. A remote MCP server gives AI assistants access to the account. The public OpenAPI 3.1 spec covers 26 operations with typed error codes, and the remote MCP server uses OAuth 2.1 with six scopes and keeps voids, refunds and filing approval away from the model. Access needs a seller account arranged through sales, API keys carry no scopes, and no API changelog, SDK or subprocessor list was found.

- Page: https://www.anchorterminal.com/tools/anrok · Markdown: https://www.anchorterminal.com/tools/anrok.md · JSON: https://www.anchorterminal.com/api/v1/tools/anrok.json
- Capabilities: tax.calculate, tax.transactions, tax.exemptions, tax.filing · endpoint: `https://api.anrok.com`

### 377. Quaderno, C (59.5)

Sales tax, VAT and GST software for online businesses from Recrea Systems, a Visma company in Spain. Its REST API calculates tax for a sale, records sales and refunds, issues invoices and credit notes and exports tax reports. A public OpenAPI 3.1 spec covers 92 operations, with a free sandbox and a status page showing no incident since July 2025. The API key has full account access, there are no idempotency keys, and the newest public API version is dated October 2024.

- Page: https://www.anchorterminal.com/tools/quaderno · Markdown: https://www.anchorterminal.com/tools/quaderno.md · JSON: https://www.anchorterminal.com/api/v1/tools/quaderno.json
- Capabilities: tax.calculate, tax.transactions, tax.invoicing · endpoint: `https://quadernoapp.com/api`

### 417. TaxJar, C (57.6)

TaxJar is Stripe's US sales tax service for businesses that sell across states. Its REST API calculates tax for an order, looks up rates by address, records orders and refunds for reporting, and stores exempt customers. A 21-operation REST API with a no-card 30-day trial, caller-chosen transaction IDs that make order pushes safe to repeat, and no status-page incident since March 2026. No OpenAPI spec or llms.txt was found, the API changelog stops at January 2022, tokens carry no scopes, and calculation is US-only for new accounts.

- Page: https://www.anchorterminal.com/tools/taxjar · Markdown: https://www.anchorterminal.com/tools/taxjar.md · JSON: https://www.anchorterminal.com/api/v1/tools/taxjar.json
- Capabilities: tax.calculate, tax.transactions, tax.exemptions, shipping.address-validation · endpoint: `https://api.taxjar.com/v2`

### 464. Vertex O Series, C (54.7)

Vertex O Series is indirect tax software from Vertex, Inc. that calculates sales tax, use tax and VAT for a transaction and records it for reporting. Agents reach it through REST v2 APIs with OAuth client credentials. Public OpenAPI 3.0 specs cover calculation, transaction management, tax area lookup and tax configuration, and guides are served as Markdown. Access needs a sales contract. No price, free tier, sandbox signup, calculation rate limit, idempotency key or official SDK was found in the reviewed documentation.

- Page: https://www.anchorterminal.com/tools/vertex-tax · Markdown: https://www.anchorterminal.com/tools/vertex-tax.md · JSON: https://www.anchorterminal.com/api/v1/tools/vertex-tax.json
- Capabilities: tax.calculate, tax.transactions, tax.exemptions, tax.invoicing · endpoint: `https://calcconnect.vertexsmb.com/vertex-ws/v2`

## How we test this category

The same twenty transactions (US states, EU countries, digital and physical goods, an exempt buyer) sent to each listing's calculation API and committed for reporting. We check the rates returned against published rates, address handling and the report that results. In this run listings are graded from public evidence against the published checklist. This test hasn't run yet, so Task success is pending and the grades here come from the categories assessed from public evidence.