Vatstack (BYOK)

Vatstack (BYOK) — connector documentation

• MCP endpoint: https://byok-vatstack.connectorbay.com/mcp
• REST API: POST https://byok-vatstack.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://byok-vatstack.connectorbay.com/openapi.json
• Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
• Authentication: your own Vatstack Vatstack secret key (sk_live_...); a public key only works for the rate tools, sent in the X-Upstream-Key header of every request (never stored, logged or cached)
• Health: https://byok-vatstack.connectorbay.com/health · Tool schemas: https://byok-vatstack.connectorbay.com/tools.json
• Publisher: Unify Dynamics LLC · connectorbay.com/byok-vatstack · agent@connectorbay.com

What Vatstack (BYOK) is for

Vatstack (BYOK) lets an AI assistant read your own Vatstack data through the Vatstack API with a key you supply (Vatstack secret key (sk_live_...); a public key only works for the rate tools). Read-only: 7 tools (list_vat_rates, get_vat_rate_by_ip, get_usage, list_vat_validations, get_vat_validation, list_vat_quotes, get_vat_quote). The BYOK key travels with each request, is used for that one call only and is never stored, logged or cached; it is only ever sent to api.vatstack.com. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Vatstack. Vatstack and its logos are trademarks of their owners and are used only to say which service the connector works with.

Ask your assistant things like:

• "What are the standard VAT rates of all EU member states?"
• "Which VAT rate applies to a customer at IP address 91.64.12.5?"
• "How many VAT validations have I used this month on Vatstack?"
• "Which VAT numbers did I validate since the start of this month?"
• "Show Vatstack validation 5d1ded3128ca7a842aaf5ed4"
• "Which VAT quotes did my shop generate recently?"

What it does

• list_vat_rates: List VAT rates by country: standard and reduced rates, digital-product category rates, currency and EU membership. Without a subscription only EU member states are returned.
• get_vat_rate_by_ip: Get the VAT rate that applies at the location of an IP address; with no address Vatstack uses the address of the caller.
• get_usage: Show how many validations and supplies the account used this month and the capacity of its plan.
• list_vat_validations: List the VAT number validations saved in your account (newest first) with validity, registered company name and address, and the VIES or HMRC consultation number. Needs a secret key.
• get_vat_validation: Get one saved VAT number validation by its id, with the validity result and consultation number. Needs a secret key.
• list_vat_quotes: List the VAT price quotes generated in your account, newest first, with country, amount, VAT treatment and the validation used. Quotes are kept for three days. Needs a secret key.
• get_vat_quote: Get one VAT quote by id: amount in cents, total, country and the VAT rate type that was applied. Needs a secret key.

BYOK key

You bring your own Vatstack Vatstack secret key (sk_live_...); a public key only works for the rate tools (https://vatstack.com/docs/authentication). Your assistant sends it in the X-Upstream-Key header with each request. ConnectorBay uses it for that one call only: it is never stored, logged or cached, never shown in an answer, and it is only sent to api.vatstack.com over https, with no redirects followed. Create a key with the fewest permissions the tools need (read-only if the provider offers it), and revoke it at the provider whenever you like.

Data sources

• https://vatstack.com/docs (the API this connector calls, with a BYOK key)

Live from the Vatstack API (api.vatstack.com) with a BYOK key; documentation: https://vatstack.com/docs. Endpoints checked against that documentation on 2026-10-16.

What it is not

Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Vatstack. Vatstack and its logos are trademarks of their owners and are used only to say which service the connector works with. It is read-only: it never creates, changes, sends or deletes anything in your Vatstack account.

Built for: Worldwide. Languages: English.

Vatstack (BYOK) — Privacy Policy

Effective 16 October 2026. Unify Dynamics LLC ("we", "us"), Menlo Park, California.

What Vatstack (BYOK) is. Vatstack (BYOK) is a connector (an MCP server and REST API) that an AI assistant calls on your behalf to read your own Vatstack data: Read VAT rates, your saved VAT number validations and VAT price quotes from Vatstack with your own API key. You bring your own Vatstack Vatstack secret key (sk_live_...); a public key only works for the rate tools; the assistant sends it to us with each request.

BYOK key. The key you supply is used to make the one Vatstack call you asked for. Our application does not store it, write it to a log, put it in a cache, or share it. It is sent only to api.vatstack.com, over https, and is removed from any text we return to you or your assistant. We do not follow redirects with your key. If Vatstack rejects it, we say so without repeating it.

What we receive. The arguments of each tool call, the BYOK key (for that call only), the technical headers needed to serve the request (an IP address or a client identifier supplied by the assistant) and standard server logs. What Vatstack receives. The request we make on your behalf, including the key and the arguments, under Vatstack's own terms and privacy policy (https://vatstack.com/terms). Vatstack acts at your direction and is the only recipient of the data of your request besides our hosting provider.

What we return. The answer Vatstack gives for your request, trimmed to the fields the tool documents. We do not keep it: it is returned to your assistant and not stored, cached or used to train anything.

What we do not do. We do not build a profile, sell or share personal information, or keep your Vatstack data. Rate-limit counters (a client identifier and timestamps) are held in memory for at most 24 hours. Hosting access logs (IP addresses, request paths and status codes) are kept for up to 30 days for security and abuse prevention; our application adds no request headers or bodies to them.

Sub-processors. Vatstack (the API you call with a BYOK key, at your direction). Hosting: Vercel (United States regions).

Your rights. Because we store no personal data beyond short-lived logs, requests to access, correct or delete data are usually satisfied automatically; you can still contact agent@connectorbay.com and we will respond within 30 days. Revoke your key at Vatstack at any time to end all access.

Children. Vatstack (BYOK) is a general-audience service operated by the adult using the assistant, under Vatstack's own age rules.

Changes. We will post changes here with a new effective date.

Vatstack (BYOK) — Terms of Service

Effective 16 October 2026. These terms govern use of the Vatstack (BYOK) connector ("the Service") operated by Unify Dynamics LLC ("we", "us").

1. The Service. Vatstack (BYOK) provides: Read VAT rates, your saved VAT number validations and VAT price quotes from Vatstack with your own API key. It is accessed through an AI assistant or directly over MCP or HTTP, and is read-only.
2. Your own key, your own account. You must use your own Vatstack credentials and only access data you are allowed to access. Vatstack's terms (https://vatstack.com/terms) apply to your use of Vatstack; you are responsible for complying with them, including any rate limits and permitted uses. Do not share a key you do not own.
3. Independent. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by Vatstack. Vatstack and its logos are trademarks of their owners and are used only to say which service the connector works with.
4. No advice, no guarantees. Output is the data Vatstack returns, lightly trimmed; it may be incomplete, delayed or changed by Vatstack. Check important facts at the source.
5. Read-only. The Service does not create, change, send or delete anything in your Vatstack account.
6. Acceptable use. Automated use within the published rate limits is welcome. Do not use the Service to access data you are not entitled to, to circumvent Vatstack's controls, or to attack any system.
7. Availability. The Service is provided "as is" without warranty. We may change, limit or discontinue it at any time; Vatstack may change or end its API at any time.
8. Data. Our Privacy Policy describes what we process. In short: the BYOK key is used for the one call and not stored or logged.
9. Pro keys. Optional ConnectorBay Pro API keys are issued at our discretion and are separate from your Vatstack key.
10. Liability. To the fullest extent permitted by law, Unify Dynamics LLC is not liable for any loss arising from use of or reliance on the Service, including any action Vatstack takes on your account. Our total liability is limited to US $100.
11. Governing law. California law; venue in San Mateo County, California.
12. Contact. Unify Dynamics LLC · agent@connectorbay.com · https://connectorbay.com/byok-vatstack

Vatstack (BYOK) support

Email agent@connectorbay.com. We answer within two business days.

• MCP endpoint: https://byok-vatstack.connectorbay.com/mcp
• REST API: https://byok-vatstack.connectorbay.com/openapi.json
• Live status: https://byok-vatstack.connectorbay.com/health

When you report a problem, include the question you asked your agent, roughly when, and which agent you used (for example Claude, ChatGPT or Gemini). Never send us passwords, account numbers or ID numbers. Vatstack (BYOK) never asks for them.