# Numeral vs TaxJar

> TaxJar scores 57.6 (C) on agent readiness against Numeral's 49.3 (D), and leads in 4 of 7 scored categories. Numeral leads on schema & documentation and agent ergonomics. Both do tax calculate. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/numeral-vs-taxjar
- Markdown: https://www.anchorterminal.com/compare/numeral-vs-taxjar.md (~2,200 tokens)
- Slim: https://www.anchorterminal.com/compare/numeral-vs-taxjar.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/numeral-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

TaxJar scores 57.6 (C) on agent readiness against Numeral's 49.3 (D), and leads in 4 of 7 scored categories. Numeral leads on schema & documentation and agent ergonomics. Both do tax calculate.

- Numeral: grade D, 49.3/100, rank #611 of 722. Markdown https://www.anchorterminal.com/tools/numeral.md · JSON https://www.anchorterminal.com/api/v1/tools/numeral.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

### Numeral (D)

Good for: An agent working for a seller or platform that has a Numeral account and needs tax at checkout, committed transactions for filing, and read access to nexus, registrations and filings through MCP.

Ahead on:
- Schema & documentation, 87 against 48
- Agent ergonomics, 71 against 61

Watch for: No status page, uptime SLA or numeric rate limit was found. The product page says rate limits can be removed on request

### 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 25
- Payments & pricing, 30 against 10
- Transparency & trust, 71 against 45

Also in its favour:
- Free to start without a card

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 | Numeral | TaxJar | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 25 | 84 | TaxJar +59 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 87 | 48 | Numeral +39 |
| Agent ergonomics | 13% (16.2 this run) | 71 | 61 | Numeral +10 |
| Security & auth | 14% (17.5 this run) | 47 | 43 | Numeral +4 |
| Payments & pricing | 10% (12.5 this run) | 10 | 30 | TaxJar +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 60 | 64 | TaxJar +4 |
| Transparency & trust | 7% (8.8 this run) | 45 | 71 | TaxJar +26 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **49.3 · D** | **57.6 · C** | |

## Facts side by side

| Fact | Numeral | TaxJar |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Numeral Two, Inc. | TaxJar (Stripe) |
| Hosted endpoint | `https://api.numeralhq.com` | `https://api.taxjar.com/v2` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under Numeral's terms of service. The Go, Python and Node SDKs are Apache-2.0 | Proprietary service under TaxJar's terms of service and API licence agreement. The official API clients on GitHub are MIT |
| Tools exposed | 14 | none |
| Read-only variant documented | yes | no |
| llms.txt | yes | no |
| Last release | 2026-09-15 | 2026-09-02 |
| Terms last updated | no date given | 2026-05-14 |
| Privacy policy last updated | no document linked | 2022-01-07 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | 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 | 0 stars, 9 npm/wk, 19 PyPI/wk | 57 stars, 95k npm/wk, 50k PyPI/wk |

## Verdicts

**Numeral.** Docs are written for agents, with a public OpenAPI spec for 32 operations, Markdown pages, llms.txt and a remote MCP server whose 14 tools are read-only by default. No status page, numeric rate limit or SLA was found, the API ignores idempotency keys, and API access is sold on a custom plan after a demo.

**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

### Numeral

1. Send `X-API-Version: 2026-03-01` on every call to `https://api.numeralhq.com`. Merchant, platform and certificate endpoints reject requests without it
2. Commit with a stable `reference_order_id`. On `REFERENCE_ORDER_ID_ALREADY_EXISTS` look up the existing transaction, because `Idempotency-Key` is ignored
3. Commit before the calculation's `expires_at`. If it has expired, calculate again and commit the new `calculation_id` with the original `reference_order_id`
4. Send `amount` as the line total in minor units to `/tax/calculations` and as the per-unit price to `/tax/platform/calculations`
5. Start with an `sk_test_` key. Certificate endpoints and MCP certificate tools are live only and answer `TESTMODE_NOT_SUPPORTED` or `live_mode_required`

### 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, Numeral or TaxJar?

TaxJar scores 57.6 (C) on agent readiness against Numeral's 49.3 (D), and leads in 4 of 7 scored categories. Numeral leads on schema & documentation and agent ergonomics.

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

Both need an API key.

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

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


## For agents

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

## Other comparisons with Numeral or TaxJar

- [Anrok vs Numeral](https://www.anchorterminal.com/compare/anrok-vs-numeral.md)
- [Anrok vs TaxJar](https://www.anchorterminal.com/compare/anrok-vs-taxjar.md)
- [Avalara AvaTax vs Numeral](https://www.anchorterminal.com/compare/avalara-vs-numeral.md)
- [Avalara AvaTax vs TaxJar](https://www.anchorterminal.com/compare/avalara-vs-taxjar.md)
- [Fonoa vs Numeral](https://www.anchorterminal.com/compare/fonoa-vs-numeral.md)
- [Fonoa vs TaxJar](https://www.anchorterminal.com/compare/fonoa-vs-taxjar.md)
- [Kintsugi vs Numeral](https://www.anchorterminal.com/compare/kintsugi-vs-numeral.md)
- [Kintsugi vs TaxJar](https://www.anchorterminal.com/compare/kintsugi-vs-taxjar.md)
- [Numeral vs Quaderno](https://www.anchorterminal.com/compare/numeral-vs-quaderno.md)
- [Numeral vs TaxCloud](https://www.anchorterminal.com/compare/numeral-vs-taxcloud.md)
- [Numeral vs Vertex O Series](https://www.anchorterminal.com/compare/numeral-vs-vertex-tax.md)
- [Numeral vs Zamp](https://www.anchorterminal.com/compare/numeral-vs-zamp.md)
- [Quaderno vs TaxJar](https://www.anchorterminal.com/compare/quaderno-vs-taxjar.md)
- [TaxCloud vs TaxJar](https://www.anchorterminal.com/compare/taxcloud-vs-taxjar.md)
- [TaxJar vs Vertex O Series](https://www.anchorterminal.com/compare/taxjar-vs-vertex-tax.md)
- [TaxJar vs Zamp](https://www.anchorterminal.com/compare/taxjar-vs-zamp.md)