diff --git a/action.yml b/action.yml
index 3729be7..88d41e7 100644
--- a/action.yml
+++ b/action.yml
@@ -1,5 +1,5 @@
 name: 'Archive UHK releases'
-description: 'Upload specific files to AWS S3'
+description: 'Upload specific files to S3-compatible object storage'
 inputs:
   FILE_PATTERN:
     description: File pattern of the upload files
@@ -19,6 +19,8 @@ inputs:
   S3_BUCKET:
     description: S3 Bucket
     required: true
+  S3_ENDPOINT:
+    description: Optional custom S3 endpoint (e.g. Backblaze B2 https://s3.<region>.backblazeb2.com)
   S3_INDEX_FILE_KEY:
     description: S3 Key of the json index file that store the extra meta data of each s3 object
   S3_KEY_PREFIX:
diff --git a/lib/utils/get-inputs.js b/lib/utils/get-inputs.js
index 280d8ab..d1575ac 100644
--- a/lib/utils/get-inputs.js
+++ b/lib/utils/get-inputs.js
@@ -10,6 +10,7 @@ import { TEST_GITHUB_REPOSITORY, TEST_GITHUB_SHA } from '../constants.js'
  * @property {string} s3AccessKey
  * @property {string} s3AccessKeyId
  * @property {string} s3Bucket
+ * @property {string} [s3Endpoint]
  * @property {string} s3IndexFileKey
  * @property {string} s3KeyPrefix
  * @property {string} s3Region
@@ -31,6 +32,7 @@ export function getInputs() {
       s3AccessKey: process.env.S3_ACCESS_KEY,
       s3AccessKeyId: process.env.S3_ACCESS_KEY_ID,
       s3Bucket: process.env.S3_BUCKET,
+      s3Endpoint: process.env.S3_ENDPOINT,
       s3IndexFileKey: process.env.S3_INDEX_FILE_KEY,
       s3KeyPrefix: process.env.S3_KEY_PREFIX,
       s3Region: process.env.S3_REGION,
@@ -43,6 +45,7 @@ export function getInputs() {
     s3AccessKey: core.getInput('S3_ACCESS_KEY', { required: true }),
     s3AccessKeyId: core.getInput('S3_ACCESS_KEY_ID', { required: true }),
     s3Bucket: core.getInput('S3_BUCKET', { required: true }),
+    s3Endpoint: core.getInput('S3_ENDPOINT') || process.env.S3_ENDPOINT,
     s3IndexFileKey: core.getInput('S3_INDEX_FILE_KEY'),
     s3KeyPrefix: core.getInput('S3_KEY_PREFIX', { required: true }),
     s3Region: core.getInput('S3_REGION', { required: true }),
diff --git a/lib/utils/get-s3-client.js b/lib/utils/get-s3-client.js
index 77713fb..7f05500 100644
--- a/lib/utils/get-s3-client.js
+++ b/lib/utils/get-s3-client.js
@@ -1,5 +1,4 @@
 import { S3 } from '@aws-sdk/client-s3'
-import process from 'node:process'
 
 /**
  * @param {Inputs} inputs
@@ -16,8 +15,8 @@ export function getS3Client(inputs) {
     region: inputs.s3Region,
   }
 
-  if (process.env.S3_ENDPOINT) {
-    options.endpoint = process.env.S3_ENDPOINT
+  if (inputs.s3Endpoint) {
+    options.endpoint = inputs.s3Endpoint
     options.forcePathStyle = true
   }