# Pennylane vs Xero API + MCP

> Xero and Pennylane score within a point of each other for accounting ledgers, 67.2 and 66.3 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/pennylane-vs-xero
- Markdown: https://www.anchorterminal.com/compare/pennylane-vs-xero.md (~2,300 tokens)
- Slim: https://www.anchorterminal.com/compare/pennylane-vs-xero.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/pennylane-vs-xero.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: 2026-10-09

Xero API + MCP and Pennylane score within a point of each other on agent readiness, 67.2 (B) and 66.3 (B). Pennylane leads on reliability and schema & documentation. Both do accounting ledgers.

- Pennylane: grade B, 66.3/100, rank #297 of 950. Markdown https://www.anchorterminal.com/tools/pennylane.md · JSON https://www.anchorterminal.com/api/v1/tools/pennylane.json
- Xero API + MCP: grade B, 67.2/100, rank #258 of 950. Markdown https://www.anchorterminal.com/tools/xero.md · JSON https://www.anchorterminal.com/api/v1/tools/xero.json
- Best accounting and invoicing APIs for AI agents: https://www.anchorterminal.com/best/accounting/index.md
- All 66 accounting comparisons: https://www.anchorterminal.com/compare/accounting/index.md

## Which one, for what

### Pennylane (B)

Good for: An agent working on the books of French companies or an accounting firm's client portfolio, with French chart of accounts, FEC export, Factur-X e-invoicing and VAT returns.

Ahead on:
- Reliability, 75 against 68
- Schema & documentation, 85 against 79

Watch for: The API agreement allows changes, suspension or revocation with or without notice and supplies the API as is

### Xero API + MCP (B)

Good for: An agent keeping the books for UK, Australian or New Zealand businesses, or any team that wants read-only scopes and long deprecation notice.

Ahead on:
- Agent ergonomics, 75 against 66
- Payments & pricing, 35 against 20
- Maintenance & community, 76 against 65

Also in its favour:
- Runs on your own machine

Watch for: Developer docs, including the per-minute rate limits, only render with JavaScript


## Score by category

| Category | Weight | Pennylane | Xero API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 75 | 68 | Pennylane +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 79 | Pennylane +6 |
| Agent ergonomics | 13% (16.2 this run) | 66 | 75 | Xero API + MCP +9 |
| Security & auth | 14% (17.5 this run) | 68 | 64 | Pennylane +4 |
| Payments & pricing | 10% (12.5 this run) | 20 | 35 | Xero API + MCP +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 65 | 76 | Xero API + MCP +11 |
| Transparency & trust | 7% (8.8 this run) | 76 | 72 | Pennylane +4 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **66.3 · B** | **67.2 · B** | |

## Facts side by side

| Fact | Pennylane | Xero API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Pennylane SAS | Xero |
| Hosted endpoint | `https://app.pennylane.com/api/external/v2` | `https://api.xero.com/api.xro/2.0` |
| Transports | HTTP | HTTP, stdio |
| Auth | OAuth or key | OAuth |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Pennylane's API agreement and customer terms | MIT |
| Tools exposed | 31 | 51 |
| Read-only variant documented | yes | no |
| llms.txt | yes | no |
| Last release | 2026-09-30 | 2026-10-01 |
| Terms last updated | no date given | 2025-12-04 |
| Privacy policy last updated | no date given | 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 | yes | not found in the text |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | none | 350 stars, 395k npm/wk, 64k PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**Pennylane.** The v2 API has per-resource read and write scopes, an OpenAPI definition on every reference page, llms.txt and a breaking-change process that ran over 24 weeks. Access needs a paid Essentiel plan or partner approval, creation endpoints are not idempotent, and the API agreement lets Pennylane change or revoke the API without notice.

**Xero API + MCP.** Granular OAuth scopes, such as accounting.reports.profitandloss.read, required for apps created from 29 April 2026. Developer docs, including the per-minute rate limits, only render with JavaScript.

## Before you call either

### Pennylane

1. Call `GET https://app.pennylane.com/api/external/v2/me` first to confirm the token, user and company context
2. Stay under 25 requests per 5 seconds per token and wait for the `retry-after` value on a 429
3. Do not retry a create after a timeout without checking first. Only supplier invoice imports are deduplicated
4. Send `filter` and `sort` again with every `cursor`. The cursor stores position only
5. Send amounts as strings such as "120.00", and ask for `:readonly` scopes when the task only reads
6. Use the MCP server for reads only. It cannot create, edit or delete, and firm connections need `company_id`

### Xero API + MCP

1. Send xero-tenant-id on every call. The token alone doesn't name the organisation
2. A bill is an Invoice with Type ACCPAY, a sales invoice is ACCREC. There's no separate bills endpoint
3. Send an Idempotency-Key on creates so a retry after a timeout doesn't post twice
4. Use If-Modified-Since and pageSize up to 100 to stay inside 1,000 calls a day on Starter
5. Set XERO_SCOPES to read scopes only when the agent shouldn't write. The MCP still lists its write and delete tools

## Questions

### Which is better for AI agents, Pennylane or Xero API + MCP?

Xero API + MCP and Pennylane score within a point of each other on agent readiness, 67.2 (B) and 66.3 (B). Pennylane leads on reliability and schema & documentation.

### Do Pennylane and Xero API + MCP need an API key?

Pennylane takes an API key or an OAuth sign-in. Xero API + MCP uses an OAuth sign-in.

### Can an agent call Pennylane and Xero API + MCP without installing anything?

Yes. Pennylane has a hosted endpoint at https://app.pennylane.com/api/external/v2 and Xero API + MCP at https://api.xero.com/api.xro/2.0.


## For agents

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

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