Add Zerion API to Data tools documentation

docs/tools/data/zerion.md

@@ -0,0 +1,81 @@
+!!! note "Content disclaimer"
+
+    Please view the third-party content disclaimer [here](https://github.com/0xPolygon/polygon-docs/blob/main/CONTENT_DISCLAIMER.md).
+
+# Zerion API
+
+Accessing wallet portfolio data, token balances, transaction history, and DeFi positions across multiple chains can be complex when building a dapp. [Zerion API](https://zerion.io/api) provides a single, normalized REST API to query wallet-level data across EVM chains and Solana, returning interpreted, human-readable financial data rather than raw blockchain information.
+
+Zerion API supports all major EVM chains, including:
+
+- Polygon PoS
+- Polygon zkEVM
+
+For the full list, see [supported chains](https://developers.zerion.io/reference/supported-blockchains).
+
+## Quick Start
+
+Getting started only takes a few minutes. Follow these three steps:
+
+1. Get an API key
+2. Make your first API call
+3. Query from your dapp
+
+Here's a step by step walk through:
+
+## 1. Get an API Key
+
+Go to the [Zerion Developer Dashboard](https://dashboard.zerion.io/) and sign up with your work email. Create an organization, and your free API key will be generated instantly. The free Developer plan includes 2,000 requests/day with no credit card required.
+
+## 2. Make Your First API Call
+
+Zerion API uses HTTP Basic authentication. The base URL is `https://api.zerion.io/v1/`.
+
+To get a wallet's token positions on Polygon:
+
+```bash
+curl -X GET "https://api.zerion.io/v1/wallets/0xYOUR_ADDRESS/positions?filter[chain_ids]=polygon" \
+  -u YOUR_API_KEY:
+```
+
+!!! note
+
+    The colon after the API key is required for Basic auth with an empty password.
+
+## 3. Query from Your Dapp
+
+Here's a sample Node.js script to fetch a wallet's Polygon token positions:
+
+```jsx
+const axios = require('axios');
+
+const API_KEY = 'YOUR_API_KEY';
+const walletAddress = '0xYOUR_ADDRESS';
+
+const config = {
+  method: 'get',
+  url: `https://api.zerion.io/v1/wallets/${walletAddress}/positions?filter[chain_ids]=polygon`,
+  auth: {
+    username: API_KEY,
+    password: '',
+  },
+};
+
+axios(config)
+  .then((response) => {
+    const positions = response.data.data;
+    positions.forEach((position) => {
+      console.log(
+        position.attributes.fungible_info.name,
+        position.attributes.quantity.float,
+      );
+    });
+  })
+  .catch((error) => {
+    console.error(error);
+  });
+```
+
+### Additional resources:
+
+- To explore all available endpoints including portfolio, transactions, DeFi positions, and NFTs, read the [API reference](https://developers.zerion.io/).

mkdocs.yml

@@ -433,6 +433,7 @@ nav:
         - Data:
           - Alchemy subgraphs: https://docs.alchemy.com/docs/how-to-build-and-deploy-a-subgraph-on-polygon-zkevm-using-alchemy-subgraphs
           - The Graph: tools/data/thegraph.md
+          - Zerion API: tools/data/zerion.md
         - Storage:
           - IPFS: tools/storage/ipfs.md
           - Filecoin: tools/storage/filecoinhelpers.md