diff --git a/examples/src/ref_finance.rs b/examples/src/ref_finance.rs
index e227a0b7..be6e0e86 100644
--- a/examples/src/ref_finance.rs
+++ b/examples/src/ref_finance.rs
@@ -47,6 +47,7 @@ async fn create_ref(
 
     owner
         .call(&worker, ref_finance.id(), "storage_deposit")
+        .args_json(serde_json::json!({}))?
         .deposit(parse_near!("30 mN"))
         .transact()
         .await?;
@@ -78,6 +79,7 @@ async fn create_wnear(
 
     owner
         .call(&worker, wnear.id(), "storage_deposit")
+        .args_json(serde_json::json!({}))?
         .deposit(parse_near!("0.008 N"))
         .transact()
         .await?;
diff --git a/workspaces/Cargo.toml b/workspaces/Cargo.toml
index b9f6566d..d7096049 100644
--- a/workspaces/Cargo.toml
+++ b/workspaces/Cargo.toml
@@ -41,5 +41,6 @@ libc = "0.2"
 
 [dev-dependencies]
 borsh = "0.9"
+near-units = "0.1.0"
 test-log = { version = "0.2.8", default-features = false, features = ["trace"] }
 tracing-subscriber = { version = "0.3.5", features = ["env-filter"] }
diff --git a/workspaces/src/network/account.rs b/workspaces/src/network/account.rs
index 8704814c..86a5a0dc 100644
--- a/workspaces/src/network/account.rs
+++ b/workspaces/src/network/account.rs
@@ -199,7 +199,7 @@ impl<'a, T: Network> CallBuilder<'a, T> {
             signer,
             contract_id,
             function,
-            args: serde_json::json!({}).to_string().into_bytes(),
+            args: vec![],
             deposit: DEFAULT_CALL_DEPOSIT,
             gas: DEFAULT_CALL_FN_GAS,
         }
diff --git a/workspaces/tests/optional_args.rs b/workspaces/tests/optional_args.rs
new file mode 100644
index 00000000..5e10a24a
--- /dev/null
+++ b/workspaces/tests/optional_args.rs
@@ -0,0 +1,57 @@
+#![recursion_limit = "256"]
+use near_units::parse_near;
+use test_log::test;
+use workspaces::prelude::*;
+use workspaces::{Contract, DevNetwork, Worker};
+
+async fn init(worker: &Worker<impl DevNetwork>) -> anyhow::Result<Contract> {
+    let contract = worker
+        .dev_deploy(include_bytes!("../../examples/res/fungible_token.wasm"))
+        .await?;
+
+    contract
+        .call(worker, "new_default_meta")
+        .args_json(serde_json::json!({
+            "owner_id": contract.id(),
+            "total_supply": parse_near!("1,000,000,000 N").to_string(),
+        }))?
+        .transact()
+        .await?;
+
+    Ok(contract)
+}
+
+#[test(tokio::test)]
+async fn test_empty_args_error() -> anyhow::Result<()> {
+    let worker = workspaces::sandbox();
+    let contract = init(&worker).await?;
+
+    let res = contract
+        .call(&worker, "storage_unregister")
+        .gas(300_000_000_000_000)
+        .deposit(1)
+        .transact()
+        .await;
+    assert!(format!("{:?}", res.unwrap_err()).contains("Failed to deserialize input from JSON"));
+
+    Ok(())
+}
+
+#[test(tokio::test)]
+async fn test_optional_args_present() -> anyhow::Result<()> {
+    let worker = workspaces::sandbox();
+    let contract = init(&worker).await?;
+
+    let res = contract
+        .call(&worker, "storage_unregister")
+        .args_json(serde_json::json!({
+            "force": true
+        }))?
+        .gas(300_000_000_000_000)
+        .deposit(1)
+        .transact()
+        .await?;
+    assert!(res.json::<bool>()?);
+
+    Ok(())
+}