diff --git a/lib/decodeOpaqueId.js b/lib/decodeOpaqueId.js
index abf465a..bbe0a71 100644
--- a/lib/decodeOpaqueId.js
+++ b/lib/decodeOpaqueId.js
@@ -1,16 +1,23 @@
+import config from "./config.js";
+
 /**
  * @name decodeOpaqueId
  * @method
  * @memberof GraphQL/Transforms
- * @summary Transforms an opaque ID to an internal ID
+ * @summary Transforms an opaque ID to an internal ID. Returns the `id`
+ *   unchanged and the `namespace` as null if the `REACTION_SHOULD_ENCODE_IDS`
+ *   environment variable is `false`
  * @param {String} opaqueId The ID to transform
  * @returns {String} An internal ID
  */
 export default function decodeOpaqueId(opaqueId) {
   if (opaqueId === undefined || opaqueId === null) return null;
 
-  const [namespace, id] = Buffer
-    .from(opaqueId, "base64")
+  if (config.REACTION_SHOULD_ENCODE_IDS === false) {
+    return { namespace: null, id: opaqueId };
+  }
+
+  const [namespace, id] = Buffer.from(opaqueId, "base64")
     .toString("utf8")
     .split(":", 2);
 
diff --git a/lib/decodeOpaqueId.test.js b/lib/decodeOpaqueId.test.js
index 6112ca5..563dc13 100644
--- a/lib/decodeOpaqueId.test.js
+++ b/lib/decodeOpaqueId.test.js
@@ -1,5 +1,14 @@
+import { jest } from "@jest/globals";
+import config from "./config.js";
 import decodeOpaqueId from "./decodeOpaqueId.js";
 
+jest.mock("./config.js", () => ({
+  __esModule: true, // this property makes it work
+  default: {
+    REACTION_SHOULD_ENCODE_IDS: true
+  }
+}));
+
 test("decodes base64", () => {
   const encodedId = "cmVhY3Rpb24vc2hvcDpieTV3cGRnM25NcThnWDU0Yw==";
   expect(decodeOpaqueId(encodedId)).toEqual({
@@ -15,3 +24,13 @@ test("passes through non-base64", () => {
     namespace: null
   });
 });
+
+test("skips decoding if REACTION_SHOULD_ENCODE_IDS env is false", async () => {
+  const id = "by5wpdg3nMq8gX54c";
+  config.REACTION_SHOULD_ENCODE_IDS = false;
+  expect(decodeOpaqueId(id)).toEqual({
+    id,
+    namespace: null
+  });
+  config.REACTION_SHOULD_ENCODE_IDS = true;
+});