diff --git a/.example.env b/.example.env
new file mode 100644
index 0000000..44ce2a6
--- /dev/null
+++ b/.example.env
@@ -0,0 +1,6 @@
+# Treasury instance within treasury metadata transactions
+# this is used to filter out metadata and transactions which are not relevant
+
+# 9e65e4ed7d6fd86fc4827d2b45da6d2c601fb920e8bfd794b8ecc619 = Intersect 2025 budget instance
+
+TREASURY_INSTANCE=
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4c49bd7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.env
diff --git a/README.md b/README.md
index c02e4af..954a0b4 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ API instance hosted at
 
 ```
 administration-data/
+├── .env                        # Environment variables (not committed)
 ├── indexer/                 # YACI Store indexer configuration
 │   ├── application.properties
 │   ├── config/
@@ -162,7 +163,14 @@ The YACI Store indexer exposes its own API on port 8081:
 
 ### Treasury Reserve Contract
 
-We can configure the Treasury Reserve instance that we index for.
+We can configure the Treasury Reserve instance that we index for via the `.env` file at the project root:
+
+```bash
+# .env
+TREASURY_INSTANCE=9e65e4ed7d6fd86fc4827d2b45da6d2c601fb920e8bfd794b8ecc619
+```
+
+This environment variable is passed to the indexer container via `docker-compose.yml` and used by the `treasury-filter.mvel` plugin script to filter metadata.
 
 | Property | Value |
 |----------|-------|
@@ -252,7 +260,7 @@ ORDER BY block_time DESC LIMIT 10;
 
 YACI Store plugins filter blockchain data to only store treasury-relevant information:
 
-- **Metadata Filter**: Only metadata with label `1694` (TOM standard) AND instance `9e65e4ed7d6fd86fc4827d2b45da6d2c601fb920e8bfd794b8ecc619`
+- **Metadata Filter**: Only metadata with label `1694` (TOM standard) AND the treasury instance configured via `TREASURY_INSTANCE` in `.env`
 
 This reduces database size by ~95% while keeping all treasury data.
 
diff --git a/docker-compose.yml b/docker-compose.yml
index e6d9356..028b4a0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -35,6 +35,8 @@ services:
     depends_on:
       postgres:
         condition: service_healthy
+    env_file:
+      - .env
     environment:
       - JAVA_OPTS=-Xmx2g -Xms1g
     ports:
diff --git a/docs/architecture.md b/docs/architecture.md
index 21aa377..184b625 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -162,8 +162,8 @@ This document describes how data flows through the Cardano Administration Data S
                            │                    │
                            ▼                    ▼
                     ┌─────────────────────────────────────┐
-                    │  instance == "9e65e4ed..." ?        │
-                    │  (Treasury instance ID)             │
+                    │  instance == TREASURY_INSTANCE ?    │
+                    │  (from env variable)                │
                     └─────────────────────────────────────┘
                            │                    │
                           YES                   NO
diff --git a/indexer/SETUP.md b/indexer/SETUP.md
index 686c148..84b78ee 100644
--- a/indexer/SETUP.md
+++ b/indexer/SETUP.md
@@ -22,6 +22,18 @@ Note: The script may fail if the release tag format is different. In that case,
 
 ## Configuration
 
+### Environment Variables
+
+Create a `.env` file in the project root with the treasury instance to filter for:
+
+```bash
+TREASURY_INSTANCE=9e65e4ed7d6fd86fc4827d2b45da6d2c601fb920e8bfd794b8ecc619
+```
+
+This is used by the `treasury-filter.mvel` plugin script to filter metadata by instance.
+
+### Application Properties
+
 Edit `application.properties` to configure:
 - Database connection details
 - Cardano network settings
diff --git a/indexer/plugins/scripts/treasury-filter.mvel b/indexer/plugins/scripts/treasury-filter.mvel
index 2bc09d2..9ee4ea8 100644
--- a/indexer/plugins/scripts/treasury-filter.mvel
+++ b/indexer/plugins/scripts/treasury-filter.mvel
@@ -1,5 +1,5 @@
 // Treasury instance identifier - only track metadata for this specific instance
-TREASURY_INSTANCE = "9e65e4ed7d6fd86fc4827d2b45da6d2c601fb920e8bfd794b8ecc619";
+TREASURY_INSTANCE = System.getenv("TREASURY_INSTANCE");
 
 // Filter metadata - only keep label 1694 with matching treasury instance
 def filterMetadata(items) {