# Vertex O Series (slim)

> 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.

- Full: https://www.anchorterminal.com/tools/vertex-tax.md (~6,950 tokens) · this version ~1,680 tokens · JSON https://www.anchorterminal.com/tools/vertex-tax.json · canonical https://www.anchorterminal.com/tools/vertex-tax
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-08

**C · 54.7/100 · rank #526 of 722 · #7 in Tax calculation & compliance · not agent-ready · confidence medium**


Assessment: 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.

## Facts

- Kind: HTTP API · vendor: Vertex, Inc. · category: Tax calculation & compliance · legal entity: Vertex, Inc. · provenance 84/100
- Endpoint: `https://calcconnect.vertexsmb.com/vertex-ws/v2` (HTTP)
- Auth: OAuth · pricing: Paid · x402: no · licence: Proprietary service under a customer agreement with Vertex, Inc. that isn't published
- Probe metrics: not measured yet (probes haven't run)
- Graded surface: O Series Cloud REST v2 APIs. No official MCP server or SDK was found
- APIs: Calculation and Tax GIS (version 2.9.0, 14 operations), Tax Configuration (v2.1.0, 29 operations), User Management and Role Management, all OpenAPI 3.0
- Calculation endpoints: POST /v2/supplies (seller), /v2/procurement (buyer) and /v2/owner, plus five tax area lookups by address, coordinates, tax area id, external jurisdiction code or batch
- Transaction management: DELETE /v2/transactions/{id}, POST /v2/transactions/{id}/reversal and /rollback, GET /v2/transaction-exists/{transactionid}. On Cloud, within 90 days of calculation
- Hosts: Cloud calculation at calcconnect.vertexsmb.com (AWS) or calcconnect.azure-na.vertexcloud.com (Azure), configuration at calcconnect.vertexsmb.com/tax-config-api, On-Demand at <customer>.ondemand.vertexinc.com, On-Premise on the customer's server
- Credentials: OAuth 2.0 client credentials, one API and one partition per Cloud credential, tokens last 3,599 seconds
- Rate limits: 10 access token requests per 8 hours on the standard token endpoint. Certificate Centre API 1,000 requests a minute. No calculation limit found
- Errors: 400, 401, 403 and 500 with an `errors` array of `code`, `message` and `target`. Configuration adds 404 and 503
- Pagination: OData `$skip`, `$top` (default 20, maximum 500) and `$filter` on configuration lists
- Exemption certificates: Certificate Centre API, version 1.0.3 in September 2026, 20 operations for customers, certificates and contacts at ccservices.vertexsmb.com
- E-invoicing: Separate e-Invoicing API with dated release notes, the latest on 16 September 2026
- Azure limits: GET /v2/changed-taxareas and /v2/changed-taxareas/{taxareaid} aren't available on the Azure calculation host
- Certifications: SOC 1 Type II and SOC 2 Type II reports for 2025 by Forvis Mazars, listed in the trust centre
- Status: status.vertexinc.com on Statuspage, 26 components including O Series Cloud and O Series On-Demand
- Sub-processors: AWS, Microsoft, Oracle, ecosio and Global VAT Compliance, with locations, updated 8 April 2026

- Scores: Reliability 65, Performance pending, Schema & documentation 74, Agent ergonomics 51, Security & auth 57, Payments & pricing 0, Task success pending, Maintenance & community 62, Transparency & trust 68 · total over the 7 assessed categories
- Why: Reliability, Read with the hosted rubric. · Schema & documentation, OpenAPI 3.0 specs for four O Series APIs download without a login from the API reference. · Agent ergonomics, Calculation responses can't be trimmed by field. · Security & auth, OAuth 2.0 client credentials. · Payments & pricing, Read with the hosted rubric. · Maintenance & community, The O Series release notes page, which now covers SR24 and calculation spec 2.9.0, was last modified on 25 September 2026. Certificate Centr… · Transparency & trust, Closed service.
- Sources: 23, open questions: 7, both in the full twin
- Capabilities: tax.calculate, tax.transactions, tax.exemptions, tax.invoicing
- JSON: https://www.anchorterminal.com/api/v1/tools/vertex-tax.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/vertex-tax.svg` or a link to https://www.anchorterminal.com/tools/vertex-tax from a page on vertexinc.com or one of its subdomains, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Cache the access token for its 3,599-second life. The standard token endpoint allows 10 requests per 8 hours, and tokenguard.vertexcloud.com returns a cached token
2. Send no `Authorization: Bearer` header to /oauth/token, and put the client id and secret in the body or a Basic header. Credentials in the URL are rejected
3. Set `saleMessageType` to QUOTATION for an estimate. INVOICE is stored for reporting and remittance
4. Call GET /v2/transaction-exists/{transactionid} before retrying a failed INVOICE. No idempotency key is documented
5. Delete, reverse or roll back a Cloud transaction within 90 days of calculation. Later requests can cause calculation errors or duplicates

## Connect

```bash
curl --location 'https://auth.vertexcloud.com/oauth/token' \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --data-urlencode 'client_id=<your-client-id>' \
  --data-urlencode 'client_secret=<your-client-secret>' \
  --data-urlencode 'audience=verx://migration-api' \
  --data-urlencode 'grant_type=client_credentials'
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/vertex-tax

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Avalara AvaTax | B | 68.8 | tax.calculate, tax.transactions, tax.exemptions, tax.invoicing | https://www.anchorterminal.com/tools/avalara.min.md |
| Anrok | C | 61.6 | tax.calculate, tax.transactions, tax.exemptions | https://www.anchorterminal.com/tools/anrok.min.md |
| Kintsugi | C | 60.7 | tax.calculate, tax.transactions, tax.exemptions | https://www.anchorterminal.com/tools/kintsugi.min.md |
| Quaderno | C | 59.5 | tax.calculate, tax.transactions, tax.invoicing | https://www.anchorterminal.com/tools/quaderno.min.md |
| TaxJar | C | 57.6 | tax.calculate, tax.transactions, tax.exemptions | https://www.anchorterminal.com/tools/taxjar.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)