# Fonoa vs Zamp

> Fonoa scores 51.7 (D) on agent readiness against Zamp's 49.5 (D), and leads in 3 of 7 scored categories. Zamp leads on reliability and payments & pricing. Both do tax calculate. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/fonoa-vs-zamp
- Markdown: https://www.anchorterminal.com/compare/fonoa-vs-zamp.md (~2,150 tokens)
- Slim: https://www.anchorterminal.com/compare/fonoa-vs-zamp.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/fonoa-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

Fonoa scores 51.7 (D) on agent readiness against Zamp's 49.5 (D), and leads in 3 of 7 scored categories. Zamp leads on reliability and payments & pricing. Both do tax calculate.

- Fonoa: grade D, 51.7/100, rank #575 of 722. Markdown https://www.anchorterminal.com/tools/fonoa.md · JSON https://www.anchorterminal.com/api/v1/tools/fonoa.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

### Fonoa (D)

Good for: An agent working for a company that already has a Fonoa contract and needs tax ID validation, VAT or GST calculation, or e-invoice reporting across many countries through one API.

Ahead on:
- Schema & documentation, 68 against 44
- Security & auth, 47 against 40
- Maintenance & community, 49 against 42

Watch for: No self-serve signup. Sandbox, demo and production keys are issued by Fonoa after contact by email or the sales form

### 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 66
- Payments & pricing, 20 against 3

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 | Fonoa | Zamp | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 66 | 72 | Zamp +6 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 68 | 44 | Fonoa +24 |
| Agent ergonomics | 13% (16.2 this run) | 64 | 64 | even |
| Security & auth | 14% (17.5 this run) | 47 | 40 | Fonoa +7 |
| Payments & pricing | 10% (12.5 this run) | 3 | 20 | Zamp +17 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 49 | 42 | Fonoa +7 |
| Transparency & trust | 7% (8.8 this run) | 48 | 50 | Zamp +2 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **51.7 · D** | **49.5 · D** | |

## Facts side by side

| Fact | Fonoa | Zamp |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Fonoa Technologies Limited | Zamp Inc. |
| Hosted endpoint | `https://api.fonoa.com` | `https://api.zamp.com` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service. The API contract is not published. The public Terms of Service took effect on 14 May 2020 and name older seller sites | 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 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-02 | 2026-08-31 |
| Terms last updated | no document linked | no date given |
| Privacy policy last updated | no date given | 2025-02-11 |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | not found in the text |

## Verdicts

**Fonoa.** The API reference is served as Markdown with an OpenAPI definition on each endpoint page, and e-invoicing submissions are idempotent by `transaction_id`. API keys are issued by Fonoa staff after contact, no price, rate limit or changelog is published, and the only public terms date from May 2020 and cover older seller sites.

**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

### Fonoa

1. Send the key in the `Ocp-Apim-Subscription-Key` header. Use the sandbox key at https://sandbox.fonoa.com and the production key at https://api.fonoa.com
2. Treat validations and e-invoicing submissions as asynchronous. POST, then poll the GET endpoint or wait for the webhook, and avoid tight polling
3. Reuse the same `transaction_id` on a retry of `/v1/transactions`. A transaction already processed is not processed again
4. Commit a calculation with POST `/tax/v2/calculations/<uuid>/commit` only when the sale is final. The commit adds it to revenue tracking
5. Ask the Fonoa contact to configure webhooks. There is no API for it, and always fetch `resource_url` as given in the webhook

### 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, Fonoa or Zamp?

Fonoa scores 51.7 (D) on agent readiness against Zamp's 49.5 (D), and leads in 3 of 7 scored categories. Zamp leads on reliability and payments & pricing.

### Do Fonoa and Zamp need an API key?

Both need an API key.

### Can an agent call Fonoa and Zamp without installing anything?

Yes. Fonoa has a hosted endpoint at https://api.fonoa.com and Zamp at https://api.zamp.com.


## For agents

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

## Other comparisons with Fonoa or Zamp

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