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Head to head · Tax calculate · October 2026 research run

Kintsugi vs Zamp

Kintsugi scores 60.7 (C) on agent readiness against Zamp's 49.5 (D), and leads in 6 of 7 scored categories. Zamp leads on payments & pricing. Both do tax calculate.

KintsugiKintsugi AI, Inc. · HTTP API C60.7/100#392 of 722 ZampZamp Inc. · HTTP API D49.5/100#609 of 722

Which one, for what

Kintsugi C

Good for An agent working for a seller that already has Kintsugi Premium and wants estimates, transaction sync, exemptions, nexus, registrations and filing status through one API, or read-only answers about an account through the OAuth MCP server.

Ahead on

  • Schema & documentation, 87 against 44
  • Agent ergonomics, 75 against 64
  • Security & auth, 52 against 40
  • Maintenance & community, 78 against 42
  • Transparency & trust, 60 against 50

Watch for

API access, SDKs and real-time tax calculation are listed only under Premium, which is priced on request. API keys need a paid plan that includes them

Zamp D

Good for An agent working for a US or Canadian seller that wants Zamp's team to register, file and remit, and needs calculation and transaction sync through a small API.

Ahead on

  • Payments & pricing, 20 against 13

Also in its favour

  • Free to start without a card
  • No incidents deducted, where Kintsugi loses 3 points for them

Watch for

No OpenAPI file for the API. The one file on the docs host is the documentation platform's plant store sample

Score by category

CategoryWeight this runKintsugiZampEdge
Reliability16%207372Kintsugi +1
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28744Kintsugi +43
Agent ergonomics13%16.27564Kintsugi +11
Security & auth14%17.55240Kintsugi +12
Payments & pricing10%12.51320Zamp +7
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87842Kintsugi +36
Transparency & trust7%8.86050Kintsugi +10
Negative events≤15-30
Total60.7 · C49.5 · D

Facts side by side

FactKintsugiZamp
KindHTTP APIHTTP API
VendorKintsugi AI, Inc.Zamp Inc.
Hosted endpointhttps://api.trykintsugi.comhttps://api.zamp.com
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyAPI key
PricingPaidPaid
x402nono
LicenceProprietary service under the Kintsugi Terms of Service. The Python SDK repository is MITProprietary service under Zamp's Standard Terms and Conditions, which form part of a signed Order Form. The sandbox has its own Developer trial terms
Tools exposed55none
Read-only variant documentedyesno
llms.txtyesyes
Last release2026-10-072026-08-31
Terms last updated2026-09-29no date given
Privacy policy last updated2025-04-132025-02-11
Customer content may train modelsyesnot found in the text
Terms restrict automated accessyesyes
Terms restrict benchmarkingyesyes
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waiveryesnot found in the text
Popularity71 npm/wk, 10 PyPI/wknone

Verdicts

Kintsugi

The docs are built for machine readers, with llms.txt, Markdown pages, a public OpenAPI 3.1 file, a dated changelog and an MCP server whose 55 tools carry read-only and destructive annotations. API keys need the custom-priced Premium plan and carry no scopes, no general rate limit is published, and breaking changes reached the pinned 2026-07-21 release in October 2026.

Zamp

A free 30-day sandbox key needs no card or sales call, and the docs are served as Markdown with llms.txt and a published limit of 1,000 requests a minute. There is no OpenAPI file, SDK, API changelog or published price, production keys come with a sales-led account, and the site footer says SOC 2 compliance is in progress.

Before you call either

Kintsugi

  1. Send Api-Key and pin Api-Version (for example 2026-10-06) on Tenanted API calls to https://api.trykintsugi.com. Without the header a request runs against 2026-07-21
  2. Use x-api-key and x-organization-id with /v1 paths for the SDKs and the docs MCP server. They don't cover the Tenanted API
  3. Call POST /tax-estimations for a quote. Nothing is stored. Record the sale with a transaction create, which answers 202, then check processingStatus before reading tax totals
  4. Always send externalId on creates. A repeat with the same externalId and source returns the stored record with 200 and doesn't apply the new fields
  5. Branch on the error code, not the message. Retry 429, 500 and 503 with exponential backoff, and restart paging from the first page on stale_cursor

Zamp

  1. Call POST /calculations for a quote and POST /transactions only when the sale is final. Put the returned taxDue in taxCollected when posting
  2. Keep transaction and line item ids to 25 characters. A repeated POST /transactions with an existing id returns 409 CONFLICT, so a retry doesn't create a second record
  3. For a refund, post a new transaction with parentId set to the sale's id and a negative quantity. Never send a negative amount on a line item
  4. Send shipToAddress.state and country set to CA for Canadian orders. POST /addresses validates US addresses only
  5. Page lists with limit (1 to 100, default 10) and cursor until nextCursor is null. GET /transactions returns only transactions written with the same key
  6. Don't store sensitive or personal data in the sandbox. Trial data is deleted after 30 days and the trial terms forbid live customer data

Questions

Which is better for AI agents, Kintsugi or Zamp?

Kintsugi scores 60.7 (C) on agent readiness against Zamp's 49.5 (D), and leads in 6 of 7 scored categories. Zamp leads on payments & pricing.

Do Kintsugi and Zamp need an API key?

Kintsugi takes an API key or an OAuth sign-in. Zamp needs an API key.

Can an agent call Kintsugi and Zamp without installing anything?

Yes. Kintsugi has a hosted endpoint at https://api.trykintsugi.com and Zamp at https://api.zamp.com.

Other comparisons with Kintsugi or Zamp

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