diff --git a/README.md b/README.md
index 57f04f4c..4f0071ac 100644
--- a/README.md
+++ b/README.md
@@ -319,6 +319,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Gmail](https://developers.google.com/gmail/api/) | Flexible, RESTful access to the user's inbox | `OAuth` | Yes | Unknown |
 | [Google Analytics](https://developers.google.com/analytics/) | Collect, configure and analyze your data to reach the right audience | `OAuth` | Yes | Unknown |
 | [Instatus](https://instatus.com/help/api) | Post to and update maintenance and incidents on your status page through an HTTP REST API | `apiKey` | Yes | Unknown |
+| [InvoiceIn](https://invoicein.peculiar.systems/) | Parse and validate received e-invoices: XRechnung, ZUGFeRD, Peppol, FatturaPA, KSeF | `apiKey` | Yes | Yes |
 | [Invovate](https://invovate.com/api) | Generate PDF, JSON & UBL invoices in 11 languages from one JSON POST | `apiKey` | Yes | No |
 | [Katalis UK Company Enrichment](https://meetkatalis.com/apis) | Verified UK company profiles with an AI summary and accuracy score, from Companies House data | `apiKey` | Yes | Unknown |
 | [Legal Sandbox Georgia](https://legal.ge/api/openapi.json) | Find verified legal specialists in Georgia from natural-language queries | No | Yes | Yes |