[DRAFT] Add API Usage Logger cookbook

docs.json

@@ -110,6 +110,7 @@
               "docs/learning-how-tos/cookbook/nodejs-proxy",
               "docs/learning-how-tos/cookbook/java-document-translator",
               "docs/learning-how-tos/cookbook/usage-analytics-dashboard",
+              "docs/learning-how-tos/cookbook/api-usage-logger",
               "docs/learning-how-tos/examples-and-guides/deepl-mcp-server-how-to-build-and-use-translation-in-llm-applications",
               "docs/learning-how-tos/cookbook/google-sheets"
             ]

docs/learning-how-tos/cookbook/api-usage-logger.mdx

@@ -0,0 +1,38 @@
+---
+title: "API Usage Logger"
+description: "Learn how to capture per-request DeepL API usage data and visualize it in a local dashboard."
+public: true
+---
+
+<Card title="GitHub - DeepLcom/deepl-api-usage-logger" icon="github" horizontal href="https://github.com/DeepLcom/deepl-api-usage-logger">
+  DeepL API Usage Logger on GitHub
+</Card>
+
+
+This open-source reference project shows how to capture per-request usage data for the DeepL API (billed characters, language pairs, reporting tags, API key identifiers, and errors) and explore it through a local Streamlit dashboard. It wraps the [DeepL Python client](/docs/getting-started/client-libraries) so every text and document translation request is logged to a local DuckDB file as it happens, alongside any errors returned by the API.
+
+The project is intended for teams that need usage reporting with request-level granularity. If you instead want to retrieve subscription-level or API key-level data via a single API call, see the [Usage Analytics Dashboard](/docs/learning-how-tos/cookbook/usage-analytics-dashboard) cookbook, which uses the [Admin API](/api-reference/admin-api/organization-usage-analytics).
+
+## Features
+
+- **Per-request logging** for both text and document translation, with the source language, target language, billed characters, and a request ID stored for every call
+- **Error capture alongside successes**, including the error code, HTTP status, and message, so reliability and usage live in the same dataset
+- **Reporting tag and API key alias support**, letting you group usage by team, project, or service
+- **Streamlit dashboard** with three views: a Usage summary table, an Error summary table, and a SQL Explorer for arbitrary DuckDB queries against the underlying table
+- **CSV export** from every dashboard view
+- **Non-blocking writes** that queue log entries on a background thread, so logging never adds latency to translation calls
+- **Local stack** of Python, DuckDB, and Streamlit, with no external services required
+
+## Screenshots
+
+<Frame>
+  <img src="/docs/learning-how-tos/cookbook/images/api-usage-logger-usage-tab.png" alt="Usage tab showing total billed characters, requests, and language pair breakdown" />
+</Frame>
+
+<Frame>
+  <img src="/docs/learning-how-tos/cookbook/images/api-usage-logger-errors-tab.png" alt="Errors tab showing failed requests grouped by error code and HTTP status" />
+</Frame>
+
+<Frame>
+  <img src="/docs/learning-how-tos/cookbook/images/api-usage-logger-sql-explorer-tab.png" alt="SQL Explorer tab for running arbitrary DuckDB queries against the translation usage table" />
+</Frame>

docs/learning-how-tos/cookbook/usage-analytics-dashboard.mdx

@@ -15,6 +15,8 @@ The dashboard is designed to be lightweight and easy to set up, with zero NPM de
 
 For more information about the DeepL Admin API endpoint, check out the [Admin API documentation](/api-reference/admin-api/organization-usage-analytics).
 
+If you need per-request logging instead of account-wide views, see the [API Usage Logger](/docs/learning-how-tos/cookbook/api-usage-logger) cookbook.
+
 ## Features
 
 - **Interactive charts and visualizations** - View your usage data through multiple chart types