diff --git a/hypersync-client/Cargo.toml b/hypersync-client/Cargo.toml
index 29d997e..00545bb 100644
--- a/hypersync-client/Cargo.toml
+++ b/hypersync-client/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "hypersync-client"
-version = "0.20.0-rc.3"
+version = "0.20.0-rc.5"
 edition = "2021"
 description = "client library for hypersync"
 license = "MPL-2.0"
diff --git a/hypersync-client/src/lib.rs b/hypersync-client/src/lib.rs
index b9c2bb5..56798f8 100644
--- a/hypersync-client/src/lib.rs
+++ b/hypersync-client/src/lib.rs
@@ -69,6 +69,20 @@ pub struct Client {
 impl Client {
     /// Creates a new client with the given configuration.
     pub fn new(cfg: ClientConfig) -> Result<Self> {
+        // hscr stands for hypersync client rust
+        let user_agent = format!("hscr/{}", env!("CARGO_PKG_VERSION"));
+        Self::new_internal(cfg, user_agent)
+    }
+
+    #[doc(hidden)]
+    pub fn new_with_agent(cfg: ClientConfig, user_agent: impl Into<String>) -> Result<Self> {
+        // Creates a new client with the given configuration and custom user agent.
+        // This is intended for use by language bindings (Python, Node.js) and HyperIndex.
+        Self::new_internal(cfg, user_agent.into())
+    }
+
+    /// Internal constructor that takes both config and user agent.
+    fn new_internal(cfg: ClientConfig, user_agent: String) -> Result<Self> {
         let timeout = cfg
             .http_req_timeout_millis
             .unwrap_or(NonZeroU64::new(30_000).unwrap());
@@ -76,6 +90,7 @@ impl Client {
         let http_client = reqwest::Client::builder()
             .no_gzip()
             .timeout(Duration::from_millis(timeout.get()))
+            .user_agent(user_agent)
             .build()
             .unwrap();