# Kintsugi vs TaxJar

> Kintsugi scores 60.7 (C) on agent readiness against TaxJar's 57.6 (C), and leads in 4 of 7 scored categories. TaxJar leads on reliability, payments & pricing and transparency & trust. Both do tax calculate. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/kintsugi-vs-taxjar
- Markdown: https://www.anchorterminal.com/compare/kintsugi-vs-taxjar.md (~2,300 tokens)
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- JSON: https://www.anchorterminal.com/compare/kintsugi-vs-taxjar.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-08

Kintsugi scores 60.7 (C) on agent readiness against TaxJar's 57.6 (C), and leads in 4 of 7 scored categories. TaxJar leads on reliability, payments & pricing and transparency & trust. Both do tax calculate.

- Kintsugi: grade C, 60.7/100, rank #392 of 722. Markdown https://www.anchorterminal.com/tools/kintsugi.md · JSON https://www.anchorterminal.com/api/v1/tools/kintsugi.json
- TaxJar: grade C, 57.6/100, rank #470 of 722. Markdown https://www.anchorterminal.com/tools/taxjar.md · JSON https://www.anchorterminal.com/api/v1/tools/taxjar.json

## 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 48
- Agent ergonomics, 75 against 61
- Security & auth, 52 against 43
- Maintenance & community, 78 against 64

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

### TaxJar (C)

Good for: An agent working for a US seller that needs sales tax on an order at checkout and a record of orders and refunds for state reporting, with exempt customers handled by ID.

Ahead on:
- Reliability, 84 against 73
- Payments & pricing, 30 against 13
- Transparency & trust, 71 against 60

Also in its favour:
- Free to start without a card
- No incidents deducted, where Kintsugi loses 3 points for them

Watch for: No OpenAPI spec or llms.txt was found. The taxjar/openapi repository on GitHub holds only a README


## Score by category

| Category | Weight | Kintsugi | TaxJar | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 73 | 84 | TaxJar +11 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 87 | 48 | Kintsugi +39 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 61 | Kintsugi +14 |
| Security & auth | 14% (17.5 this run) | 52 | 43 | Kintsugi +9 |
| Payments & pricing | 10% (12.5 this run) | 13 | 30 | TaxJar +17 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 78 | 64 | Kintsugi +14 |
| Transparency & trust | 7% (8.8 this run) | 60 | 71 | TaxJar +11 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **60.7 · C** | **57.6 · C** | |

## Facts side by side

| Fact | Kintsugi | TaxJar |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Kintsugi AI, Inc. | TaxJar (Stripe) |
| Hosted endpoint | `https://api.trykintsugi.com` | `https://api.taxjar.com/v2` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under the Kintsugi Terms of Service. The Python SDK repository is MIT | Proprietary service under TaxJar's terms of service and API licence agreement. The official API clients on GitHub are MIT |
| Tools exposed | 55 | none |
| Read-only variant documented | yes | no |
| llms.txt | yes | no |
| Last release | 2026-10-07 | 2026-09-02 |
| Terms last updated | 2026-09-29 | 2026-05-14 |
| Privacy policy last updated | 2025-04-13 | 2022-01-07 |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | yes | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 71 npm/wk, 10 PyPI/wk | 57 stars, 95k npm/wk, 50k PyPI/wk |

## 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.

**TaxJar.** A 21-operation REST API with a no-card 30-day trial, caller-chosen transaction IDs that make order pushes safe to repeat, and no status-page incident since March 2026. No OpenAPI spec or llms.txt was found, the API changelog stops at January 2022, tokens carry no scopes, and calculation is US-only for new accounts.

## 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`

### TaxJar

1. Send `x-api-version: 2022-01-24` on every call. Accounts opened before 3 February 2022 default to an older version with weaker validation
2. Pass `nexus_addresses[]` or keep nexus states in the account. Without nexus the API returns zero tax and reports no error
3. Create orders with your own `transaction_id`. On 422 the order already exists, so send a PUT to update it
4. Post JSON with `Content-Type: application/json`. Form-encoded arrays such as `line_items[]` can return 406
5. Cache calculations and skip states without nexus. Each calculation or rate lookup counts as a tenth of an order, errors included

## Questions

### Which is better for AI agents, Kintsugi or TaxJar?

Kintsugi scores 60.7 (C) on agent readiness against TaxJar's 57.6 (C), and leads in 4 of 7 scored categories. TaxJar leads on reliability, payments & pricing and transparency & trust.

### Do Kintsugi and TaxJar need an API key?

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

### Can an agent call Kintsugi and TaxJar without installing anything?

Yes. Kintsugi has a hosted endpoint at https://api.trykintsugi.com and TaxJar at https://api.taxjar.com/v2.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/kintsugi-vs-taxjar.json, and with the fewest tokens: https://www.anchorterminal.com/compare/kintsugi-vs-taxjar.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "kintsugi", "b": "taxjar"}`. From a terminal: `anchor compare kintsugi taxjar`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/kintsugi.json and https://www.anchorterminal.com/api/v1/tools/taxjar.json

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