# Invoice Ninja API vs Pennylane

> Pennylane scores 66.3 (B) to Invoice Ninja's 52.1 (D) for invoicing. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/invoice-ninja-vs-pennylane
- Markdown: https://www.anchorterminal.com/compare/invoice-ninja-vs-pennylane.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/invoice-ninja-vs-pennylane.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/invoice-ninja-vs-pennylane.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

Pennylane scores 66.3 (B) on agent readiness against Invoice Ninja API's 52.1 (D), and leads in 5 of 7 scored categories. Invoice Ninja API leads on payments & pricing and maintenance & community. Both do invoicing.

- Invoice Ninja API: grade D, 52.1/100, rank #738 of 950. Markdown https://www.anchorterminal.com/tools/invoice-ninja.md · JSON https://www.anchorterminal.com/api/v1/tools/invoice-ninja.json
- 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
- 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

### Invoice Ninja API (D)

Good for: An agent that quotes, invoices, chases and records payments for a small business, or for anyone who wants the billing system on their own server.

Ahead on:
- Payments & pricing, 35 against 20
- Maintenance & community, 83 against 65

Watch for: No general ledger, journals or balance sheet, so the bookkeeping half of the category test can't be done

### 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 36
- Schema & documentation, 85 against 66
- Agent ergonomics, 66 against 60
- Security & auth, 68 against 48
- Transparency & trust, 76 against 62

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


## Score by category

| Category | Weight | Invoice Ninja API | Pennylane | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 36 | 75 | Pennylane +39 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 66 | 85 | Pennylane +19 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 66 | Pennylane +6 |
| Security & auth | 14% (17.5 this run) | 48 | 68 | Pennylane +20 |
| Payments & pricing | 10% (12.5 this run) | 35 | 20 | Invoice Ninja API +15 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 65 | Invoice Ninja API +18 |
| Transparency & trust | 7% (8.8 this run) | 62 | 76 | Pennylane +14 |
| Negative events | ≤15 | -1 | 0 | |
| **Total** | | **52.1 · D** | **66.3 · B** | |

## Facts side by side

| Fact | Invoice Ninja API | Pennylane |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Invoice Ninja | Pennylane SAS |
| Hosted endpoint | `https://invoicing.co/api/v1` | `https://app.pennylane.com/api/external/v2` |
| Transports | HTTP | HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | Elastic License 2.0 | Proprietary service under Pennylane's API agreement and customer terms |
| Tools exposed | none | 31 |
| Read-only variant documented | no | yes |
| llms.txt | no | yes |
| Last release | 2026-09-18 | 2026-09-30 |
| Terms last updated | 2026-02-14 | no date given |
| Privacy policy last updated | 2026-02-14 | no date given |
| 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 | yes |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 10k stars | none |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

**Invoice Ninja API.** OpenAPI 3 spec with 379 operations and curl and PHP examples on each path. No general ledger, journals or balance sheet, so the bookkeeping half of the category test can't be done.

**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.

## Before you call either

### Invoice Ninja API

1. Send X-Requested-With: XMLHttpRequest with X-API-TOKEN on every call
2. Prototype against demo.invoiceninja.com with X-API-TOKEN: TOKEN before asking for real credentials
3. Add ?mark_sent=true to the save to make an invoice live, or ?send_email=true to send it. A plain create is a draft
4. Stay under 1,000 requests a minute per token on the hosted service and 20 a minute on report exports
5. Record a supplier bill as an expense or purchase order. There's no bills resource

### 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`

## Questions

### Which is better for AI agents, Invoice Ninja API or Pennylane?

Pennylane scores 66.3 (B) on agent readiness against Invoice Ninja API's 52.1 (D), and leads in 5 of 7 scored categories. Invoice Ninja API leads on payments & pricing and maintenance & community.

### Do Invoice Ninja API and Pennylane need an API key?

Invoice Ninja API needs an API key. Pennylane takes an API key or an OAuth sign-in.

### Can an agent call Invoice Ninja API and Pennylane without installing anything?

Yes. Invoice Ninja API has a hosted endpoint at https://invoicing.co/api/v1 and Pennylane at https://app.pennylane.com/api/external/v2.


## For agents

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

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