diff --git a/Cargo.lock b/Cargo.lock
index 22218d1..acca8b1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -259,6 +259,25 @@ dependencies = [
  "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "derive_builder"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "derive_builder_core 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "derive_builder_core"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "digest"
 version = "0.7.2"
@@ -319,6 +338,7 @@ dependencies = [
  "arrayref 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "base64 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "chrono 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "derive_builder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hkdf 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1473,6 +1493,8 @@ dependencies = [
 "checksum crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2760899e32a1d58d5abb31129f8fae5de75220bc2176e77ff7c627ae45c918d9"
 "checksum crossbeam-utils 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d636a8b3bcc1b409d7ffd3facef8f21dcb4009626adbd0c5e6c4305c07253c7b"
 "checksum crypto-mac 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0999b4ff4d3446d4ddb19a63e9e00c1876e75cd7000d20e57a693b4b3f08d958"
+"checksum derive_builder 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8c998e6ab02a828dd9735c18f154e14100e674ed08cb4e1938f0e4177543f439"
+"checksum derive_builder_core 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "735e24ee9e5fa8e16b86da5007856e97d592e11867e45d76e0c0d0a164a0b757"
 "checksum digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "00a49051fef47a72c9623101b19bd71924a45cca838826caae3eaa4d00772603"
 "checksum dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "09c3753c3db574d215cba4ea76018483895d7bff25a31b49ba45db21c48e50ab"
 "checksum encoding_rs 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "98fd0f24d1fb71a4a6b9330c8ca04cbd4e7cc5d846b54ca74ff376bc7c9f798d"
diff --git a/api/Cargo.toml b/api/Cargo.toml
index 11045ca..f39e0e8 100644
--- a/api/Cargo.toml
+++ b/api/Cargo.toml
@@ -8,6 +8,7 @@ workspace = ".."
 arrayref = "0.3"
 base64 = "0.9"
 chrono = "0.4"
+derive_builder = "0.5"
 failure = "0.1"
 failure_derive = "0.1"
 hkdf = "0.3"
diff --git a/api/src/action/params.rs b/api/src/action/params.rs
index 87b44f8..49cf07b 100644
--- a/api/src/action/params.rs
+++ b/api/src/action/params.rs
@@ -149,7 +149,8 @@ impl<'a> Params<'a> {
 }
 
 /// The parameters data object, that is sent to the server.
-#[derive(Clone, Debug, Serialize)]
+// TODO: make sure downloads are in-bound when using the builder
+#[derive(Clone, Debug, Builder, Serialize)]
 pub struct ParamsData {
     /// The number of times this file may be downloaded.
     /// This value must be in the `(0,20)` bounds, as enforced by Send servers.
diff --git a/api/src/lib.rs b/api/src/lib.rs
index 196f7f2..e58f6d7 100644
--- a/api/src/lib.rs
+++ b/api/src/lib.rs
@@ -1,5 +1,7 @@
 #[macro_use]
 extern crate arrayref;
+#[macro_use]
+extern crate derive_builder;
 extern crate failure;
 #[macro_use]
 extern crate failure_derive;
diff --git a/cli/src/action/params.rs b/cli/src/action/params.rs
index 2668257..44bdfd7 100644
--- a/cli/src/action/params.rs
+++ b/cli/src/action/params.rs
@@ -1,6 +1,6 @@
 use ffsend_api::action::params::{
     Params as ApiParams,
-    ParamsData,
+    ParamsDataBuilder,
 };
 use ffsend_api::file::remote_file::RemoteFile;
 use ffsend_api::reqwest::Client;
@@ -37,8 +37,11 @@ impl<'a> Params<'a> {
 
         // TODO: show an informative error if the owner token isn't set
 
-        // Build the params data object
-        let data = ParamsData::from(self.cmd.downloads());
+        // Build the parameters data object
+        let data = ParamsDataBuilder::default()
+            .downloads(self.cmd.downloads())
+            .build()
+            .unwrap();
 
         // TODO: make sure the data isn't empty
 
diff --git a/cli/src/action/upload.rs b/cli/src/action/upload.rs
index dfff772..402c581 100644
--- a/cli/src/action/upload.rs
+++ b/cli/src/action/upload.rs
@@ -41,12 +41,11 @@ impl<'a> Upload<'a> {
 
         // Build a parameters object to set for the file
         let params = {
-            // Build an empty parameters object
-            let mut params = ParamsData::new();
-
-            // Set the downloads
-            // TODO: do not unwrap, handle the error
-            params.set_downloads(self.cmd.downloads()).unwrap();
+            // Build the parameters data object
+            let mut params = ParamsDataBuilder::default()
+                .download(self.cmd.downloads())
+                .build()
+                .unwrap();
 
             // Wrap the data in an option if not empty
             if params.is_empty() {