diff --git a/src/garageS3.jl b/src/garageS3.jl
index 3e83440..bc8d555 100644
--- a/src/garageS3.jl
+++ b/src/garageS3.jl
@@ -14,11 +14,11 @@ using AWS, AWSS3
 # this file use local AWS config
 
 """ Example
-const storage = GarageStorage(
-    "https://s3-api.yiem.cc",
-    "GKb080154a2e5b19100b1b2c6e",     # key ID  (create at garage-ui.yiem.cc)
-    "a2c6b1379c2f731d3e6e5a408dd4d6cffca7511717675f55114ff94828febca1",   # key ID's secret key
-    "sommpanion-s3"
+storage = GarageStorage(
+  "https://s3-api.yiem.cc",
+  "GKb080154a2e5b19100b1b2c6e",     # key ID  (create at garage-ui.yiem.cc)
+  "a2c6b1379c2f731d3e6e5a408dd4d6cffca7511717675f55114ff94828febca1",   # key ID's secret key
+  "sommpanion-s3"
 )
 
 # Safe to run inside concurrent HTTP handlers (e.g., Oxygen.jl, HTTP.jl)
@@ -34,9 +34,11 @@ curl -v \
   -H 'Host: sommpanion-s3.s3-web.yiem.cc' \
   http://192.168.88.106:3902/users-1002.json
 
+# test with API
+data = String(get_file(storage, "users-1005.json"))
 
 # test with a browser
-https://s3-web.mydomain.com/my_bucket_name/users-1002.json
+https://s3-web.mydomain.com/my_bucket_name/users-1005.json
 
 """
 
@@ -103,10 +105,6 @@ end
 # 2. Thread-Safe Storage Client Wrapper
 # ===================================================================
 
-struct GarageStorage
-    config::GarageConfig
-    bucket::String
-end
 """ Create a thread-safe Garage S3 storage client.
 
 # Arguments
@@ -128,16 +126,65 @@ end
 
 # Examples
 ```jldoctest
-julia> storage = GarageStorage("https://s3-api.yiem.cc", "GKb080154a2e5b19100b1b2c6e", "a2c6b1379c2f731d3e6e5a408dd4d6cffca7511717675f55114ff94828febca1", "sommpanion-s3")
+julia> storage = GarageStorage("https://s3-api.yiem.cc", "GKb08015", "55114ff94828febca1", "sommpanion-s3")
 GarageStorage(GarageConfig(...), "sommpanion-s3")
 ```
 """
+struct GarageStorage
+    config::GarageConfig
+    bucket::String
+end
 function GarageStorage(endpoint::String, key::String, secret::String, bucket::String; region::String="garage")
     creds = SimpleCredentials(key, secret, "")
     config = GarageConfig(endpoint, region, creds)
     return GarageStorage(config, bucket)
 end
 
+""" Upload an object to the Garage S3 bucket (callable wrapper).
+
+# Arguments
+- `key::String`
+  The object key (name) in the bucket. Must not contain slashes (`/`).
+- `data::Union{String, Vector{UInt8}}`
+  The data to upload.
+
+# Return
+- `String`: The file download URL if the upload succeeds.
+- `nothing` if the key contains slashes (upload aborted with warning).
+
+# Notes
+- Slashes in keys are prohibited to prevent S3 listing issues. Use a flat naming
+  convention (e.g., `"users-1002.json"` instead of `"users/1002.json"`).
+
+# Examples
+```jldoctest
+julia> storage = GarageStorage("https://s3-api.yiem.cc", "GKb08015", "55114ff94828febca1", "sommpanion-s3")
+
+julia> url = put_file(storage)("test.json", "{\"status\": \"active\"}")
+Successfully uploaded:  test.json
+"https://s3-api.yiem.cc/sommpanion-s3/test.json"
+```
+"""
+struct put_file
+  storage::GarageStorage
+end
+function (pf::put_file)(key::String, data::Union{String, Vector{UInt8}})
+  # Check if the key contains a slash (virtual folder character)
+  if occursin('/', key)
+      @warn "Upload aborted! Slashes ('/') are not allowed in keys ('$key') to prevent S3 listing issues. Use a flat naming convention instead (e.g., 'users-1002.json')."
+      return nothing
+  end
+  
+  # Proceed if the key is flat
+  s3_put(pf.storage.config, pf.storage.bucket, key, data)
+  println("Successfully uploaded: ", key)
+
+  # file download URL
+  objURL = "$(pf.storage.config.endpoint)/$(pf.storage.bucket)/$key"
+
+  return objURL
+end
+
 """ Upload an object to the Garage S3 bucket.
 
 # Arguments