diff --git a/beacon_node/http_api/src/lib.rs b/beacon_node/http_api/src/lib.rs
index 536d19912f..9e6022dc95 100644
--- a/beacon_node/http_api/src/lib.rs
+++ b/beacon_node/http_api/src/lib.rs
@@ -96,7 +96,7 @@ use warp::http::StatusCode;
 use warp::hyper::Body;
 use warp::sse::Event;
 use warp::Reply;
-use warp::{http::Response, Filter};
+use warp::{http::Response, Filter, Rejection};
 use warp_utils::{query::multi_key_query, uor::UnifyingOrFilter};
 
 const API_PREFIX: &str = "eth";
@@ -453,7 +453,7 @@ pub fn serve<T: BeaconChainTypes>(
         warp::any()
             .and(network_globals.clone())
             .and(chain_filter.clone())
-            .and_then(
+            .then(
                 move |network_globals: Arc<NetworkGlobals<T::EthSpec>>,
                       chain: Arc<BeaconChain<T>>| async move {
                     match *network_globals.sync_state.read() {
@@ -488,8 +488,7 @@ pub fn serve<T: BeaconChainTypes>(
                         )),
                     }
                 },
-            )
-            .untuple_one();
+            );
 
     // Create a `warp` filter that provides access to the logger.
     let inner_ctx = ctx.clone();
@@ -3058,10 +3057,12 @@ pub fn serve<T: BeaconChainTypes>(
         .and(log_filter.clone())
         .then(
             |epoch: Epoch,
+             not_synced_filter: Result<(), Rejection>,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>,
              log: Logger| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     proposer_duties::proposer_duties(epoch, &chain, &log)
                 })
             },
@@ -3087,6 +3088,7 @@ pub fn serve<T: BeaconChainTypes>(
             |endpoint_version: EndpointVersion,
              slot: Slot,
              accept_header: Option<api_types::Accept>,
+             not_synced_filter: Result<(), Rejection>,
              query: api_types::ValidatorBlocksQuery,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>,
@@ -3098,6 +3100,8 @@ pub fn serve<T: BeaconChainTypes>(
                         "slot" => slot
                     );
 
+                    not_synced_filter?;
+
                     if endpoint_version == V3 {
                         produce_block_v3(accept_header, chain, slot, query).await
                     } else {
@@ -3124,11 +3128,13 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |slot: Slot,
+             not_synced_filter: Result<(), Rejection>,
              query: api_types::ValidatorBlocksQuery,
              accept_header: Option<api_types::Accept>,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.spawn_async_with_rejection(Priority::P0, async move {
+                    not_synced_filter?;
                     produce_blinded_block_v2(EndpointVersion(2), accept_header, chain, slot, query)
                         .await
                 })
@@ -3146,9 +3152,12 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |query: api_types::ValidatorAttestationDataQuery,
+             not_synced_filter: Result<(), Rejection>,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
+
                     let current_slot = chain
                         .slot()
                         .map_err(warp_utils::reject::beacon_chain_error)?;
@@ -3181,9 +3190,11 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |query: api_types::ValidatorAggregateAttestationQuery,
+             not_synced_filter: Result<(), Rejection>,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     chain
                         .get_aggregated_attestation_by_slot_and_root(
                             query.slot,
@@ -3222,10 +3233,12 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |epoch: Epoch,
+             not_synced_filter: Result<(), Rejection>,
              indices: api_types::ValidatorIndexData,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     attester_duties::attester_duties(epoch, &indices.0, &chain)
                 })
             },
@@ -3248,10 +3261,12 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |epoch: Epoch,
+             not_synced_filter: Result<(), Rejection>,
              indices: api_types::ValidatorIndexData,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     sync_committees::sync_committee_duties(epoch, &indices.0, &chain)
                 })
             },
@@ -3268,9 +3283,11 @@ pub fn serve<T: BeaconChainTypes>(
         .and(chain_filter.clone())
         .then(
             |sync_committee_data: SyncContributionData,
+             not_synced_filter: Result<(), Rejection>,
              task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     chain
                         .get_aggregated_sync_committee_contribution(&sync_committee_data)
                         .map_err(|e| {
@@ -3301,11 +3318,13 @@ pub fn serve<T: BeaconChainTypes>(
         .and(network_tx_filter.clone())
         .and(log_filter.clone())
         .then(
-            |task_spawner: TaskSpawner<T::EthSpec>,
+            |not_synced_filter: Result<(), Rejection>,
+             task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>,
              aggregates: Vec<SignedAggregateAndProof<T::EthSpec>>,
              network_tx: UnboundedSender<NetworkMessage<T::EthSpec>>, log: Logger| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     let seen_timestamp = timestamp_now();
                     let mut verified_aggregates = Vec::with_capacity(aggregates.len());
                     let mut messages = Vec::with_capacity(aggregates.len());
@@ -3414,12 +3433,14 @@ pub fn serve<T: BeaconChainTypes>(
         .and(network_tx_filter)
         .and(log_filter.clone())
         .then(
-            |task_spawner: TaskSpawner<T::EthSpec>,
+            |not_synced_filter: Result<(), Rejection>,
+             task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>,
              contributions: Vec<SignedContributionAndProof<T::EthSpec>>,
              network_tx: UnboundedSender<NetworkMessage<T::EthSpec>>,
              log: Logger| {
                 task_spawner.blocking_json_task(Priority::P0, move || {
+                    not_synced_filter?;
                     sync_committees::process_signed_contribution_and_proofs(
                         contributions,
                         network_tx,
@@ -3494,11 +3515,13 @@ pub fn serve<T: BeaconChainTypes>(
         .and(log_filter.clone())
         .and(warp_utils::json::json())
         .then(
-            |task_spawner: TaskSpawner<T::EthSpec>,
+            |not_synced_filter: Result<(), Rejection>,
+             task_spawner: TaskSpawner<T::EthSpec>,
              chain: Arc<BeaconChain<T>>,
              log: Logger,
              preparation_data: Vec<ProposerPreparationData>| {
                 task_spawner.spawn_async_with_rejection(Priority::P0, async move {
+                    not_synced_filter?;
                     let execution_layer = chain
                         .execution_layer
                         .as_ref()
@@ -4197,8 +4220,11 @@ pub fn serve<T: BeaconChainTypes>(
         .and(task_spawner_filter.clone())
         .and(chain_filter.clone())
         .then(
-            |task_spawner: TaskSpawner<T::EthSpec>, chain: Arc<BeaconChain<T>>| {
+            |not_synced_filter: Result<(), Rejection>,
+             task_spawner: TaskSpawner<T::EthSpec>,
+             chain: Arc<BeaconChain<T>>| {
                 task_spawner.blocking_json_task(Priority::P1, move || {
+                    not_synced_filter?;
                     chain.store_migrator.process_reconstruction();
                     Ok("success")
                 })