Category · Domain data
Sales tax and VAT calculation APIs for AI agents
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.
Capability keys tax.calculate · tax.transactions · tax.filing · tax.exemptions · tax.invoicing · All tools
letme.dev/tax.calculate picks the top-graded tool in this list and says how to call it direct; calling through letme comes later.
The same listing from the live API. Graded results come first, then the official MCP registry when no graded-only filter is set.
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| Compare | # | Tool | Category | Grade | Score | Agent rating | p95 | Context | Price / x402 | Auth | Where | Details |
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| 142 | Avalara AvaTaxAvalara, Inc. · HTTP API | Tax | B | 68.8 | none | n/a | n/a | $79 / mo | OAuth or key | Hosted | ||
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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. Top strength Public Swagger 2.0 file with 491 operations, plus llms.txt and a Markdown page with a curl example for each endpoint Top weakness Production rate limits are not published. The only numbers found are the trial limits and 5 calls a minute on report exports |
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| 288 | AnrokAnrok, Inc. · HTTP API | Tax | C | 61.6 | none | n/a | n/a | $100 / mo | OAuth or key | Hosted | ||
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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. Top strength Public OpenAPI 3.1 spec at apidocs.anrok.com/openapi.yaml with 26 operations, 45 enums and typed error codes on 409 responses Top weakness No self-serve signup. Starter is $100 per market a month through "Talk to us", and Custom is quoted by sales |
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| 341 | QuadernoRecrea Systems, SL · HTTP API | Tax | C | 59.5 | none | n/a | n/a | $29 / mo | OAuth or key | Hosted | ||
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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. Top strength Public OpenAPI 3.1 spec with 92 operations across tax rates, transactions, invoices, credit notes, reporting and webhooks Top weakness One API key reads and writes everything its user can reach. Scopes exist only on Connect OAuth tokens (read_only, read_write) |
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| 379 | TaxJarTaxJar (Stripe) · HTTP API | Tax | C | 57.6 | none | n/a | n/a | $99 / mo | API key | Hosted | ||
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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. Top strength 30-day trial with Professional plan access, the API included, and no card needed at signup Top weakness No OpenAPI spec or llms.txt was found. The taxjar/openapi repository on GitHub holds only a README |
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| 419 | Vertex O SeriesVertex, Inc. · HTTP API | Tax | C | 54.7 | none | n/a | n/a | Paid | OAuth | Hosted | ||
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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. Top strength OpenAPI 3.0 specs download without a login. Calculation and Tax GIS is version 2.9.0 with 14 operations, Tax Configuration v2.1.0 with 29 Top weakness No public price, free tier or self-serve signup. The security guide sends new users to the Vertex sales team for an account |
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Nothing matches these filters. .
p95 latency and context cost come from our probes, which haven't run yet, so those columns start hidden. Grades run from AA to F, and agent-ready means BB or better. Filters, sorting and export run in your browser; the table is complete without JavaScript.
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.
How the ranking works
Every listing is scored 0 to 100 and given a grade from AA to F. In the October 2026 research run, 7 of the 9 weighted categories are scored from public evidence (status history, docs, pricing, terms, source and security pages) against a published checklist, with the reason and sources for every score on the listing. Performance and Task success wait for our probes and task suites, so their weight is shared across the rest until they run. Negative events deduct up to 15 points. Read the methodology.
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