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Head to head · Tax calculate · October 2026 research run

Kintsugi vs Quaderno

Kintsugi scores 60.7 (C) on agent readiness against Quaderno's 59.5 (C), and leads in 4 of 7 scored categories. Quaderno leads on reliability, payments & pricing and transparency & trust. Both do tax calculate.

KintsugiKintsugi AI, Inc. · HTTP API C60.7/100#392 of 722 QuadernoRecrea Systems, SL · HTTP API C59.5/100#427 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 77
  • Agent ergonomics, 75 against 56
  • Security & auth, 52 against 39
  • Maintenance & community, 78 against 28

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

Quaderno C

Good for An agent working for a SaaS, digital-goods or e-commerce seller that needs a tax rate at checkout, a record of each sale with location evidence, and compliant invoices, including Spanish Verifactu and TicketBAI.

Ahead on

  • Reliability, 91 against 73
  • Payments & pricing, 30 against 13
  • Transparency & trust, 76 against 60

Also in its favour

  • No incidents deducted, where Kintsugi loses 3 points for them

Watch for

One API key reads and writes everything its user can reach. Scopes exist only on Connect OAuth tokens (read_only, read_write)

Score by category

CategoryWeight this runKintsugiQuadernoEdge
Reliability16%207391Quaderno +18
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28777Kintsugi +10
Agent ergonomics13%16.27556Kintsugi +19
Security & auth14%17.55239Kintsugi +13
Payments & pricing10%12.51330Quaderno +17
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87828Kintsugi +50
Transparency & trust7%8.86076Quaderno +16
Negative events≤15-30
Total60.7 · C59.5 · C

Facts side by side

FactKintsugiQuaderno
KindHTTP APIHTTP API
VendorKintsugi AI, Inc.Recrea Systems, SL
Hosted endpointhttps://api.trykintsugi.comhttps://quadernoapp.com/api
TransportsHTTP, Streamable HTTPHTTP
AuthOAuth or keyOAuth or key
PricingPaidPaid
x402nono
LicenceProprietary service under the Kintsugi Terms of Service. The Python SDK repository is MITProprietary service under Quaderno's terms of service. The Ruby library on GitHub is MIT
Tools exposed55none
Read-only variant documentedyesno
llms.txtyesyes
Last release2026-10-072026-07-04
Terms last updated2026-09-292026-09-15
Privacy policy last updated2025-04-132024-05-16
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 textyes
Arbitration or class-action waiveryesnot found in the text
Popularity71 npm/wk, 10 PyPI/wk15 stars

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.

Quaderno

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.

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

Quaderno

  1. Call GET https://quadernoapp.com/api/authorization first. Its href gives the account subdomain that every other call needs
  2. Before retrying a failed POST /transactions, list invoices by processor_id to check whether the sale was recorded. There is no idempotency key
  3. Treat GET /invoices/{id}/deliver as a write. It emails the invoice to the customer
  4. Correct a final invoice with a credit note. DELETE on invoices returns 410 and PUT accepts only notes, tags, metadata and address fields
  5. Read X-RateLimit-Remaining and X-RateLimit-Reset, and page with created_before and limit up to 100

Questions

Which is better for AI agents, Kintsugi or Quaderno?

Kintsugi scores 60.7 (C) on agent readiness against Quaderno's 59.5 (C), and leads in 4 of 7 scored categories. Quaderno leads on reliability, payments & pricing and transparency & trust.

Do Kintsugi and Quaderno need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call Kintsugi and Quaderno without installing anything?

Yes. Kintsugi has a hosted endpoint at https://api.trykintsugi.com and Quaderno at https://quadernoapp.com/api.

Other comparisons with Kintsugi or Quaderno

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