# Avalara AvaTax vs Zamp

> Avalara AvaTax scores 68.8 (B) on agent readiness against Zamp's 49.5 (D), and leads in 6 of 7 scored categories. Zamp leads on reliability. Both do tax calculate. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/avalara-vs-zamp
- Markdown: https://www.anchorterminal.com/compare/avalara-vs-zamp.md (~2,300 tokens)
- Slim: https://www.anchorterminal.com/compare/avalara-vs-zamp.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/avalara-vs-zamp.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

Avalara AvaTax scores 68.8 (B) on agent readiness against Zamp's 49.5 (D), and leads in 6 of 7 scored categories. Zamp leads on reliability. Both do tax calculate.

- Avalara AvaTax: grade B, 68.8/100, rank #172 of 722. Markdown https://www.anchorterminal.com/tools/avalara.md · JSON https://www.anchorterminal.com/api/v1/tools/avalara.json
- Zamp: grade D, 49.5/100, rank #609 of 722. Markdown https://www.anchorterminal.com/tools/zamp.md · JSON https://www.anchorterminal.com/api/v1/tools/zamp.json

## Which one, for what

### Avalara AvaTax (B)

Good for: An agent that must calculate and record US sales tax at address level, with VAT and GST in other countries, and hand the records to filing.

Ahead on:
- Schema & documentation, 85 against 44
- Agent ergonomics, 84 against 64
- Security & auth, 65 against 40
- Payments & pricing, 30 against 20
- Maintenance & community, 79 against 42
- Transparency & trust, 79 against 50

Watch for: Production rate limits are not published. The only numbers found are the trial limits and 5 calls a minute on report exports

### 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:
- Reliability, 72 against 62

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

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

| Category | Weight | Avalara AvaTax | Zamp | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 62 | 72 | Zamp +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 44 | Avalara AvaTax +41 |
| Agent ergonomics | 13% (16.2 this run) | 84 | 64 | Avalara AvaTax +20 |
| Security & auth | 14% (17.5 this run) | 65 | 40 | Avalara AvaTax +25 |
| Payments & pricing | 10% (12.5 this run) | 30 | 20 | Avalara AvaTax +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 79 | 42 | Avalara AvaTax +37 |
| Transparency & trust | 7% (8.8 this run) | 79 | 50 | Avalara AvaTax +29 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **68.8 · B** | **49.5 · D** | |

## Facts side by side

| Fact | Avalara AvaTax | Zamp |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Avalara, Inc. | Zamp Inc. |
| Hosted endpoint | `https://rest.avatax.com/api/v2` | `https://api.zamp.com` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under the Avalara Service Terms. The SDKs on GitHub are Apache-2.0. The MCP repository holds a README only, with no licence file | Proprietary 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 exposed | 10 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `com.avalara/avatax` | not listed |
| Last release | 2026-09-16 | 2026-08-31 |
| Terms last updated | 2023-05-01 | no date given |
| Privacy policy last updated | 2022-08-08 | 2025-02-11 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| 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 | not found in the text | not found in the text |
| Popularity | 5 stars, 331k npm/wk, 38k PyPI/wk | none |

## Verdicts

**Avalara AvaTax.** The REST API has a public Swagger file with 491 operations, a Markdown page per endpoint and a 90-day trial with no card. Production rate limits and prices per transaction are not published, the API patch notes stop at April 2023, and the tax calculation service was degraded for about 23 hours on 5 and 6 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

### Avalara AvaTax

1. Omit `type` or send SalesOrder for an estimate. A type ending in Invoice is recorded, and `commit` set to true locks it for reporting
2. Retry a timed-out invoice with CreateOrAdjustTransaction, not CreateTransaction, which errors when a committed transaction has the same code
3. Use sandbox-rest.avatax.com with sandbox credentials for tests. Production is rest.avatax.com and the two accounts are separate
4. Add `$include=SummaryOnly` or LinesOnly to shrink transaction responses, and page lists with `$top` (1,000 at most) and `$skip`
5. Call /api/v2/utilities/ping first. It answers without credentials and shows whether the credentials sent were accepted

### 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, Avalara AvaTax or Zamp?

Avalara AvaTax scores 68.8 (B) on agent readiness against Zamp's 49.5 (D), and leads in 6 of 7 scored categories. Zamp leads on reliability.

### Do Avalara AvaTax and Zamp need an API key?

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

### Can an agent call Avalara AvaTax and Zamp without installing anything?

Yes. Avalara AvaTax has a hosted endpoint at https://rest.avatax.com/api/v2 and Zamp at https://api.zamp.com.


## For agents

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

## Other comparisons with Avalara AvaTax or Zamp

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