diff --git a/src/main.rs b/src/main.rs
index c4e9eb40..dfdef905 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -187,6 +187,9 @@ struct Web3ProxyState {
     // TODO: LoudRpcs and BalancedRpcs should probably share a trait or something
     balanced_rpc_tiers: Vec<BalancedRpcs>,
     private_rpcs: LoudRpcs,
+    /// lock this when all rate limiters are hit
+    balanced_rpc_ratelimiter_lock: RwLock<()>,
+    private_rpcs_ratelimiter_lock: RwLock<()>,
 }
 
 impl Web3ProxyState {
@@ -205,6 +208,8 @@ impl Web3ProxyState {
                 .map(|servers| BalancedRpcs::new(servers, &clock))
                 .collect(),
             private_rpcs: LoudRpcs::new(private_rpcs, &clock),
+            balanced_rpc_ratelimiter_lock: Default::default(),
+            private_rpcs_ratelimiter_lock: Default::default(),
         }
     }
 
@@ -220,6 +225,8 @@ impl Web3ProxyState {
         {
             // there are private rpcs configured and the request is eth_sendSignedTransaction. send to all private rpcs
             loop {
+                let read_lock = self.private_rpcs_ratelimiter_lock.read().await;
+
                 match self.private_rpcs.get_upstream_servers().await {
                     Ok(upstream_servers) => {
                         if let Ok(result) = self
@@ -230,16 +237,23 @@ impl Web3ProxyState {
                         }
                     }
                     Err(not_until) => {
-                        // TODO: some sort of lock here?
-                        // TODO: there should probably be a lock on this so that other queries wait
+                        drop(read_lock);
+
+                        let write_lock = self.balanced_rpc_ratelimiter_lock.write().await;
+
                         let deadline = not_until.wait_time_from(self.clock.now());
                         sleep(deadline).await;
+
+                        drop(write_lock);
                     }
                 };
             }
         } else {
             // this is not a private transaction (or no private relays are configured)
             loop {
+                let read_lock = self.balanced_rpc_ratelimiter_lock.read().await;
+
+                // there are multiple tiers. save the earliest not_until (if any). if we don't return, we will sleep until then and then try again
                 let mut earliest_not_until = None;
 
                 for balanced_rpcs in self.balanced_rpc_tiers.iter() {
@@ -275,11 +289,17 @@ impl Web3ProxyState {
                     }
                 }
 
+                drop(read_lock);
+
+                let write_lock = self.balanced_rpc_ratelimiter_lock.write().await;
+
                 // TODO: some sort of lock here?
                 // we haven't returned an Ok, sleep and try again
                 // unwrap should be safe since we would have returned if it wasn't set
                 let deadline = earliest_not_until.unwrap().wait_time_from(self.clock.now());
                 sleep(deadline).await;
+
+                drop(write_lock);
             }
         }
     }