diff --git a/libs/opsqueue_python/python/opsqueue/exceptions.py b/libs/opsqueue_python/python/opsqueue/exceptions.py
index e1ae2bb..615dc95 100644
--- a/libs/opsqueue_python/python/opsqueue/exceptions.py
+++ b/libs/opsqueue_python/python/opsqueue/exceptions.py
@@ -153,6 +153,34 @@ class SubmissionNotCompletedYetError(IncorrectUsageError):
     pass
 
 
+class TooManyMatchingSubmissionsError(IncorrectUsageError):
+    """
+    Raised when a strategic-metadata lookup matches more submissions
+    than the server's configured maximum (``max_submissions_returned``).
+
+    Narrow the query with more specific strategic metadata, or raise the
+    server's configured maximum.
+    """
+
+    __slots__ = ["max_submissions"]
+
+    def __init__(
+        self,
+        max_submissions: int,
+    ):
+        super().__init__()
+        self.max_submissions = max_submissions
+
+    def __str__(self) -> str:
+        return (
+            f"The lookup matched more submissions than the configured "
+            f"maximum of {self.max_submissions}"
+        )
+
+    def __repr__(self) -> str:
+        return str(self)
+
+
 # Internal errors:
 
 
diff --git a/libs/opsqueue_python/python/opsqueue/producer.py b/libs/opsqueue_python/python/opsqueue/producer.py
index 5c6a7f0..7a93da5 100644
--- a/libs/opsqueue_python/python/opsqueue/producer.py
+++ b/libs/opsqueue_python/python/opsqueue/producer.py
@@ -18,6 +18,7 @@
     SubmissionFailedError,
     SubmissionNotCancellableError,
     SubmissionNotFoundError,
+    TooManyMatchingSubmissionsError,
 )
 from .opsqueue_internal import (  # type: ignore[import-not-found]
     SubmissionId,
@@ -38,10 +39,15 @@
     "SubmissionNotCancellable",
     "SubmissionNotCancellableError",
     "SubmissionNotFoundError",
+    "TooManyMatchingSubmissionsError",
     "ChunkFailed",
 ]
 
 
+class LookupIdsWithEmptyStrategicMetadataError(Exception):
+    pass
+
+
 class ProducerClient:
     """
     Opsqueue producer client. Allows sending of large collections of operations ('submissions')
@@ -367,6 +373,25 @@ def lookup_submission_id_by_prefix(self, prefix: str) -> SubmissionId | None:
         """
         return self.inner.lookup_submission_id_by_prefix(prefix)
 
+    def lookup_submission_ids_by_strategic_metadata(
+        self, strategic_metadata: dict[str, int]
+    ) -> list[SubmissionId]:
+        """Attempts to find in-progress submissions where the strategic metadata
+        of that submission includes all of the key-value pairs of the given
+        'strategic_metadata'. A matching submission must include all of the
+        given key-value pairs, but it may also contain other key-value pairs.
+
+        Raises:
+        - `TooManyMatchingSubmissionsError` if the lookup matches more
+          submissions than the server's configured maximum. Narrow the query
+          with more specific strategic metadata.
+        - `InternalProducerClientError` if there is a low-level internal error.
+
+        """
+        return self.inner.lookup_submission_ids_by_strategic_metadata(  # type: ignore[no-any-return]
+            strategic_metadata
+        )
+
     def is_completed(self, submission_id: SubmissionId) -> bool:
         raise NotImplementedError
 
diff --git a/libs/opsqueue_python/src/errors.rs b/libs/opsqueue_python/src/errors.rs
index f0c6850..aafd96e 100644
--- a/libs/opsqueue_python/src/errors.rs
+++ b/libs/opsqueue_python/src/errors.rs
@@ -5,7 +5,7 @@ use std::error::Error;
 use opsqueue::common::chunk::ChunkId;
 use opsqueue::common::errors::{
     ChunkNotFound, IncorrectUsage, SubmissionNotCancellable, SubmissionNotFound,
-    UnexpectedOpsqueueConsumerServerResponse, E,
+    TooManyMatchingSubmissions, UnexpectedOpsqueueConsumerServerResponse, E,
 };
 use pyo3::exceptions::PyBaseException;
 use pyo3::{import_exception, Bound, PyErr, Python};
@@ -22,6 +22,7 @@ import_exception!(opsqueue.exceptions, TryFromIntError);
 import_exception!(opsqueue.exceptions, ChunkNotFoundError);
 import_exception!(opsqueue.exceptions, SubmissionNotFoundError);
 import_exception!(opsqueue.exceptions, SubmissionNotCancellableError);
+import_exception!(opsqueue.exceptions, TooManyMatchingSubmissionsError);
 import_exception!(opsqueue.exceptions, NewObjectStoreClientError);
 import_exception!(opsqueue.exceptions, SubmissionNotCompletedYetError);
 
@@ -146,6 +147,12 @@ impl From<CError<SubmissionNotFound>> for PyErr {
     }
 }
 
+impl From<CError<TooManyMatchingSubmissions>> for PyErr {
+    fn from(value: CError<TooManyMatchingSubmissions>) -> Self {
+        TooManyMatchingSubmissionsError::new_err(value.0 .0)
+    }
+}
+
 pub struct SubmissionFailed(
     pub crate::common::SubmissionFailed,
     pub crate::common::ChunkFailed,
diff --git a/libs/opsqueue_python/src/producer.rs b/libs/opsqueue_python/src/producer.rs
index 7d4266c..1a45750 100644
--- a/libs/opsqueue_python/src/producer.rs
+++ b/libs/opsqueue_python/src/producer.rs
@@ -10,7 +10,7 @@ use pyo3::{
 use futures::{stream::BoxStream, StreamExt, TryStreamExt};
 use opsqueue::{
     common::errors::E::{self, L, R},
-    common::errors::{SubmissionNotCancellable, SubmissionNotFound},
+    common::errors::{SubmissionNotCancellable, SubmissionNotFound, TooManyMatchingSubmissions},
     object_store::{ChunksStorageError, NewObjectStoreClientError},
     producer::client::{Client as ActualClient, InternalProducerClientError},
 };
@@ -189,6 +189,31 @@ impl ProducerClient {
         })
     }
 
+    /// Attempts to find the IDs of submission matching ALL key-values pairs of
+    /// the given strategic metadata.
+    pub fn lookup_submission_ids_by_strategic_metadata(
+        &self,
+        py: Python<'_>,
+        strategic_metadata: StrategicMetadataMap,
+    ) -> CPyResult<
+        Vec<SubmissionId>,
+        E![
+            FatalPythonException,
+            TooManyMatchingSubmissions,
+            InternalProducerClientError
+        ],
+    > {
+        py.allow_threads(|| {
+            self.block_unless_interrupted(async {
+                self.producer_client
+                    .lookup_submission_ids_by_strategic_metadata(&strategic_metadata)
+                    .await
+                    .map(|res| res.into_iter().map(Into::into).collect())
+                    .map_err(|e| CError(R(e)))
+            })
+        })
+    }
+
     /// Directly inserts a submission without sending the chunks to GCS
     /// (but immediately embedding them in the DB).
     /// NOTE: This does not support StrategicMetadata currently
diff --git a/libs/opsqueue_python/tests/conftest.py b/libs/opsqueue_python/tests/conftest.py
index 4b0ebb4..e6945ea 100644
--- a/libs/opsqueue_python/tests/conftest.py
+++ b/libs/opsqueue_python/tests/conftest.py
@@ -53,7 +53,7 @@ def opsqueue() -> Generator[OpsqueueProcess, None, None]:
 
 @contextmanager
 def opsqueue_service(
-    *, port: int | None = None
+        *, port: int | None = None, command_args: Iterable[str] = ()
 ) -> Generator[OpsqueueProcess, None, None]:
     global test_opsqueue_port_offset
 
@@ -75,6 +75,7 @@ def opsqueue_service(
         str(port),
         "--database-filename",
         temp_dbname,
+        *command_args,
     ]
     env = os.environ.copy()  # We copy the env so e.g. RUST_LOG and other env vars are propagated from outside of the invocation of pytest
     if env.get("RUST_LOG") is None:
diff --git a/libs/opsqueue_python/tests/test_roundtrip.py b/libs/opsqueue_python/tests/test_roundtrip.py
index ad10541..4db7636 100644
--- a/libs/opsqueue_python/tests/test_roundtrip.py
+++ b/libs/opsqueue_python/tests/test_roundtrip.py
@@ -14,6 +14,7 @@
     SubmissionNotFoundError,
     SubmissionNotCancellable,
     SubmissionNotCancellableError,
+    TooManyMatchingSubmissionsError,
 )
 from opsqueue.consumer import ConsumerClient, Chunk
 from opsqueue.common import SerializationFormat
@@ -21,11 +22,11 @@
     background_process,
     multiple_background_processes,
     OpsqueueProcess,
+    opsqueue_service,
     StrategyDescription,
     strategy_from_description,
 )
 import logging
-
 import pytest
 
 
@@ -508,3 +509,77 @@ def consume(x: int) -> int | None:
         with pytest.raises(SubmissionFailedError) as exc_info:
             producer_client.blocking_stream_completed_submission(submission_id)
         assert exc_info.value.submission.chunks_done == len(chunks) - 1
+
+
+def test_lookup_submission_ids_by_strategic_metadata(opsqueue: OpsqueueProcess) -> None:
+    """Lookup of submission IDs should only match in progress submissions with
+    all pieces of strategic metadata.
+
+    """
+    url = "file:///tmp/opsqueue/test_lookup_submission_ids_by_strategic_metadata"
+    producer_client = ProducerClient(f"localhost:{opsqueue.port}", url)
+    id_1 = producer_client.insert_submission(
+        [1], chunk_size=1, strategic_metadata={"foo": 1, "bar": 2, "wow": 3}
+    )
+    id_2 = producer_client.insert_submission(
+        [1], chunk_size=1, strategic_metadata={"foo": 1, "bar": 2, "moo": 3}
+    )
+    # Inserting some similar data to that above, which shouldn't get matched.
+    producer_client.insert_submission(
+        [1], chunk_size=1, strategic_metadata={"foo": 2, "bar": 1}
+    )
+
+    def test_lookup(
+        strategic_metadata: dict[str, int], expected_ids: list[int]
+    ) -> None:
+        found_ids = producer_client.lookup_submission_ids_by_strategic_metadata(
+            strategic_metadata
+        )
+        assert isinstance(found_ids, list)
+        assert all(map(lambda x: isinstance(x, SubmissionId), found_ids))
+        assert found_ids == expected_ids
+
+    test_lookup({"foo": 1}, [id_1, id_2])
+    test_lookup({"foo": 1, "bar": 2}, [id_1, id_2])
+    test_lookup({"foo": 1, "MISS": 2}, [])
+    test_lookup({"wow": 3}, [id_1])
+
+    # Should only match in-progress submission.
+    producer_client.cancel_submission(id_1)
+    test_lookup({"foo": 1}, [id_2])
+
+
+def test_lookup_submission_ids_by_empty_strategic_metadata(
+    opsqueue: OpsqueueProcess,
+) -> None:
+    """Lookup of submission IDs with empty strategic_metadata should NOT raise
+    an exception.
+
+    """
+    url = "file:///tmp/opsqueue/test_lookup_submission_ids_by_empty_strategic_metadata"
+    producer_client = ProducerClient(f"localhost:{opsqueue.port}", url)
+    count = 6
+    for _ in range(count):
+        producer_client.insert_submission([1], chunk_size=1)
+    assert len(producer_client.lookup_submission_ids_by_strategic_metadata({})) == count
+
+def test_lookup_too_many_submission_ids_by_strategic_metadata() -> None:
+    """Lookup of too many submission IDs beyond the configured limit raises
+    TooManyMatchingSubmissionsError.
+
+    """
+    max_ = 2
+    # We didn't request the OpsQueueProcess as a parameter so an instance isn't
+    # started, instead we start one here with custom args.
+    with opsqueue_service(command_args=["--max-submissions-returned", str(max_)]) as opsqueue:
+        url = "file:///tmp/opsqueue/test_lookup_too_many_matching_submissions"
+        producer_client = ProducerClient(f"localhost:{opsqueue.port}", url)
+        inserted = 0
+        for _ in range(max_ + 1):
+            producer_client.insert_submission(
+                [1], chunk_size=1, strategic_metadata={"k": 1}
+            )
+            inserted += 1
+        with pytest.raises(TooManyMatchingSubmissionsError):
+            assert inserted == max_ + 1 # Make sure Exception wasn't raised too early.
+            producer_client.lookup_submission_ids_by_strategic_metadata({"k": 1})
diff --git a/opsqueue/src/common/errors.rs b/opsqueue/src/common/errors.rs
index f30436e..f48fea3 100644
--- a/opsqueue/src/common/errors.rs
+++ b/opsqueue/src/common/errors.rs
@@ -49,6 +49,10 @@ pub enum SubmissionNotCancellable {
     Cancelled(SubmissionCancelled),
 }
 
+#[derive(Error, Debug, Deserialize, Serialize)]
+#[error("Too many submissions matched the lookup, the maximum is {0:?}")]
+pub struct TooManyMatchingSubmissions(pub u64);
+
 #[derive(Error, Debug)]
 #[error("Unexpected opsqueue consumer server response. This indicates an error inside Opsqueue itself: {0:?}")]
 pub struct UnexpectedOpsqueueConsumerServerResponse(pub SyncServerToClientResponse);
diff --git a/opsqueue/src/common/mod.rs b/opsqueue/src/common/mod.rs
index a654274..65aadba 100644
--- a/opsqueue/src/common/mod.rs
+++ b/opsqueue/src/common/mod.rs
@@ -12,3 +12,50 @@ pub mod submission;
 /// consider hashing them and using that hash as MetaStateVal.
 pub type MetaStateVal = i64;
 pub type StrategicMetadataMap = FxHashMap<String, MetaStateVal>;
+
+/// Maximum number of submissions a lookup may return.
+/// Constructor checks: MaxSubmissions + 1 <= i64::MAX;
+#[derive(Debug, Clone, Copy)]
+pub struct MaxSubmissions(u64);
+
+impl MaxSubmissions {
+    pub fn new(value: u64) -> Result<Self, MaxSubmissionsTooLarge> {
+        if value < i64::MAX as u64 {
+            Ok(Self(value))
+        } else {
+            Err(MaxSubmissionsTooLarge(value))
+        }
+    }
+}
+
+impl From<MaxSubmissions> for u64 {
+    fn from(max_submissions: MaxSubmissions) -> u64 {
+        max_submissions.0
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+#[error("max_submissions value {0} is too large; it must be at most i64::MAX - 1")]
+pub struct MaxSubmissionsTooLarge(pub u64);
+
+impl std::fmt::Display for MaxSubmissions {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ParseMaxSubmissionsError {
+    #[error(transparent)]
+    NotANumber(#[from] std::num::ParseIntError),
+    #[error(transparent)]
+    TooLarge(#[from] MaxSubmissionsTooLarge),
+}
+
+impl std::str::FromStr for MaxSubmissions {
+    type Err = ParseMaxSubmissionsError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let value: u64 = s.parse()?;
+        Ok(MaxSubmissions::new(value)?)
+    }
+}
diff --git a/opsqueue/src/common/submission.rs b/opsqueue/src/common/submission.rs
index e5998f6..d1706e9 100644
--- a/opsqueue/src/common/submission.rs
+++ b/opsqueue/src/common/submission.rs
@@ -269,15 +269,17 @@ impl Submission {
 pub mod db {
     use crate::{
         common::{
-            errors::{DatabaseError, SubmissionNotCancellable, SubmissionNotFound, E},
-            StrategicMetadataMap,
+            errors::{
+                DatabaseError, SubmissionNotCancellable, SubmissionNotFound,
+                TooManyMatchingSubmissions, E,
+            },
+            MaxSubmissions, StrategicMetadataMap,
         },
         db::{Connection, True, WriterConnection, WriterPool},
     };
-    use chunk::ChunkSize;
-    use sqlx::{query, Sqlite};
-
     use axum_prometheus::metrics::{counter, histogram};
+    use chunk::ChunkSize;
+    use sqlx::{query, query_scalar, QueryBuilder, Row, Sqlite};
 
     use super::*;
 
@@ -550,6 +552,66 @@ pub mod db {
         Ok(row.map(|row| row.id))
     }
 
+    pub async fn lookup_ids_by_strategic_metadata(
+        strategic_metadata: StrategicMetadataMap,
+        max_submissions: MaxSubmissions,
+        mut conn: impl Connection,
+    ) -> Result<Vec<SubmissionId>, E<DatabaseError, TooManyMatchingSubmissions>> {
+        // MaxSubmissions provides us with the guarantee this won't overflow.
+        let limit = (u64::from(max_submissions) + 1) as i64;
+
+        // If 'max_submissions' results is exceeded return an explicit error.
+        fn error_if_too_many(
+            max_submissions: MaxSubmissions,
+            ids: Vec<SubmissionId>,
+        ) -> Result<Vec<SubmissionId>, E<DatabaseError, TooManyMatchingSubmissions>> {
+            if ids.len() as u64 > u64::from(max_submissions) {
+                Err(E::R(TooManyMatchingSubmissions(u64::from(max_submissions))))
+            } else {
+                Ok(ids)
+            }
+        }
+
+        // The main query below to match on strategic_metadata will fail at
+        // run-time if strategic_metadata is empty (because the query will
+        // produce `IN ()`). So we handle the empty case here separately.
+        if strategic_metadata.is_empty() {
+            let ids = query_scalar!(
+                r#"SELECT id AS "id: SubmissionId" FROM submissions ORDER by id LIMIT ?"#,
+                limit
+            )
+            .fetch_all(conn.get_inner())
+            .await?;
+            return error_if_too_many(max_submissions, ids);
+        }
+        // SQLx currently only supports "WHERE X IN (a, ...)" queries for postgres:
+        // https://github.com/transact-rs/sqlx/blob/main/FAQ.md#how-can-i-do-a-select--where-foo-in--query
+        // So we workaround this by manually building the query, foregoing
+        // sqlx's nice type-checking.
+        let mut query_builder: QueryBuilder<Sqlite> = QueryBuilder::new(
+            "
+            SELECT submission_id
+            FROM submissions_metadata
+            INNER JOIN submissions on submissions.id = submission_id
+            WHERE (metadata_key, metadata_value) IN (
+        ",
+        );
+        query_builder.push_values(strategic_metadata.iter(), |mut b, sm| {
+            b.push_bind(sm.0).push_bind(sm.1);
+        });
+        query_builder.push(") GROUP BY submission_id HAVING count(*) = ");
+        query_builder.push_bind(strategic_metadata.len() as i64);
+        query_builder.push(" ORDER BY submission_id limit ");
+        query_builder.push_bind(limit);
+        let rows = query_builder.build().fetch_all(conn.get_inner()).await?;
+        error_if_too_many(
+            max_submissions,
+            rows.into_iter()
+                .map(|row| row.get("submission_id"))
+                .collect(),
+        )
+    }
+
     #[tracing::instrument(skip(conn))]
     pub async fn submission_status(
         id: SubmissionId,
diff --git a/opsqueue/src/config.rs b/opsqueue/src/config.rs
index 08acd42..4af004c 100644
--- a/opsqueue/src/config.rs
+++ b/opsqueue/src/config.rs
@@ -6,6 +6,12 @@ use std::num::NonZero;
 
 use clap::Parser;
 
+use crate::common::MaxSubmissions;
+
+fn default_max_submissions_returned() -> MaxSubmissions {
+    MaxSubmissions::new(100_000).expect("Valid MaxSubmissions default")
+}
+
 /// Making big work horizontally scalable.
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
@@ -77,6 +83,11 @@ pub struct Config {
 
     #[arg(long, default_value = "1 hour")]
     pub max_submission_age: humantime::Duration,
+
+    /// Maximum number of submission IDs that a single
+    /// `lookup_submission_ids_by_strategic_metadata` request may return.
+    #[arg(long, default_value_t = default_max_submissions_returned())]
+    pub max_submissions_returned: MaxSubmissions,
 }
 
 impl Default for Config {
@@ -92,6 +103,7 @@ impl Default for Config {
         let max_missable_heartbeats = 3;
         let max_chunk_retries = 10;
         let max_submission_age = humantime::Duration::from_str("1 hour").expect("valid humantime");
+        let max_submissions_returned = default_max_submissions_returned();
         Config {
             port,
             database_filename,
@@ -101,6 +113,7 @@ impl Default for Config {
             max_missable_heartbeats,
             max_chunk_retries,
             max_submission_age,
+            max_submissions_returned,
         }
     }
 }
diff --git a/opsqueue/src/producer/client.rs b/opsqueue/src/producer/client.rs
index b09e20b..6bf8503 100644
--- a/opsqueue/src/producer/client.rs
+++ b/opsqueue/src/producer/client.rs
@@ -8,8 +8,9 @@ use http::StatusCode;
 use crate::{
     common::{
         errors::E::{L, R},
-        errors::{SubmissionNotCancellable, SubmissionNotFound},
+        errors::{SubmissionNotCancellable, SubmissionNotFound, TooManyMatchingSubmissions},
         submission::{SubmissionId, SubmissionStatus},
+        StrategicMetadataMap,
     },
     tracing::CarrierMap,
     E,
@@ -226,6 +227,54 @@ impl Client {
         .await
     }
 
+    pub async fn lookup_submission_ids_by_strategic_metadata(
+        &self,
+        strategic_metadata: &StrategicMetadataMap,
+    ) -> Result<Vec<SubmissionId>, E![TooManyMatchingSubmissions, InternalProducerClientError]>
+    {
+        (|| async {
+            let base_url = &self.base_url;
+            let response = self
+                .http_client
+                .post(format!(
+                    "{base_url}/submissions/lookup_ids_by_strategic_metadata"
+                ))
+                .json(strategic_metadata)
+                .send()
+                .await
+                .map_err(|e| R(e.into()))?;
+            let status = response.status();
+            match status {
+                // 200, the lookup succeeded.
+                StatusCode::OK => {
+                    let submission_ids = response
+                        .json::<Vec<SubmissionId>>()
+                        .await
+                        .map_err(|e| R(e.into()))?;
+                    Ok(submission_ids)
+                }
+                // 400, matched more submissions than the configured maximum.
+                StatusCode::BAD_REQUEST => {
+                    let too_many_err = response
+                        .json::<TooManyMatchingSubmissions>()
+                        .await
+                        .map_err(|e| R(e.into()))?;
+                    Err(L(too_many_err))
+                }
+                _ => Err(R(InternalProducerClientError::UnexpectedStatus(status))),
+            }
+        })
+        .retry(retry_policy())
+        .when(|e| match e {
+            L(_) => false,
+            R(client_err) => client_err.is_ephemeral(),
+        })
+        .notify(|err, dur| {
+            tracing::debug!("retrying error {err:?} with sleeping {dur:?}");
+        })
+        .await
+    }
+
     /// Get the server's version from the `/version` endpoint.
     ///
     /// A successful result will be the value of [`VERSION_CARGO_SEMVER`][crate::VERSION_CARGO_SEMVER]
diff --git a/opsqueue/src/producer/server.rs b/opsqueue/src/producer/server.rs
index 0298a2b..2788d07 100644
--- a/opsqueue/src/producer/server.rs
+++ b/opsqueue/src/producer/server.rs
@@ -2,7 +2,9 @@ use std::sync::Arc;
 
 use crate::common::errors::E::{L, R};
 use crate::common::submission::{self, SubmissionId};
+use crate::common::{MaxSubmissions, StrategicMetadataMap};
 use crate::db::{self, DBPools};
+use axum::extract;
 use axum::extract::{Path, State};
 use axum::http::StatusCode;
 use axum::response::{IntoResponse, Response};
@@ -13,7 +15,8 @@ use tokio::sync::Notify;
 use super::common::{ChunkContents, InsertSubmission};
 
 pub async fn serve_for_tests(database_pool: DBPools, server_addr: Box<str>) {
-    ServerState::new(database_pool, Arc::new(Notify::new()))
+    let max_submissions = crate::config::Config::default().max_submissions_returned;
+    ServerState::new(database_pool, Arc::new(Notify::new()), max_submissions)
         .serve_for_tests(server_addr)
         .await;
 }
@@ -22,13 +25,19 @@ pub async fn serve_for_tests(database_pool: DBPools, server_addr: Box<str>) {
 pub struct ServerState {
     pool: DBPools,
     notify_on_insert: Arc<Notify>,
+    max_submissions: MaxSubmissions,
 }
 
 impl ServerState {
-    pub fn new(pool: DBPools, notify_on_insert: Arc<Notify>) -> Self {
+    pub fn new(
+        pool: DBPools,
+        notify_on_insert: Arc<Notify>,
+        max_submissions: MaxSubmissions,
+    ) -> Self {
         ServerState {
             pool,
             notify_on_insert,
+            max_submissions,
         }
     }
     pub async fn serve_for_tests(self, server_addr: Box<str>) {
@@ -60,6 +69,10 @@ impl ServerState {
                 "/submissions/lookup_id_by_prefix/{prefix}",
                 get(lookup_submission_id_by_prefix),
             )
+            .route(
+                "/submissions/lookup_ids_by_strategic_metadata",
+                post(lookup_submission_ids_by_strategic_metadata),
+            )
             .route("/submissions/{submission_id}", get(submission_status))
             .route("/version", get(crate::server::version_endpoint)) // We're also exposing it here so the producer client can view it
             .with_state(self)
@@ -133,6 +146,30 @@ async fn lookup_submission_id_by_prefix(
     Ok(Json(submission_id))
 }
 
+/// 200 if the query was successful.
+/// 400 if the query exceeded the maximum lookup amount.
+async fn lookup_submission_ids_by_strategic_metadata(
+    State(state): State<ServerState>,
+    extract::Json(strategic_metadata): extract::Json<StrategicMetadataMap>,
+) -> Result<Json<Vec<SubmissionId>>, Response> {
+    let mut conn = state
+        .pool
+        .reader_conn()
+        .await
+        .map_err(|e| ServerError(e.into()).into_response())?;
+    match submission::db::lookup_ids_by_strategic_metadata(
+        strategic_metadata,
+        state.max_submissions,
+        &mut conn,
+    )
+    .await
+    {
+        Ok(submission_ids) => Ok(Json(submission_ids)),
+        Err(L(db_err)) => Err(ServerError(db_err.into()).into_response()),
+        Err(R(too_many_err)) => Err((StatusCode::BAD_REQUEST, Json(too_many_err)).into_response()),
+    }
+}
+
 #[tracing::instrument(level = "debug", skip(state))]
 async fn insert_submission(
     State(state): State<ServerState>,
diff --git a/opsqueue/src/server.rs b/opsqueue/src/server.rs
index cfc9ec4..58c2bec 100644
--- a/opsqueue/src/server.rs
+++ b/opsqueue/src/server.rs
@@ -80,8 +80,12 @@ pub fn build_router(
     )
     .run_background()
     .build_router();
-    let producer_routes =
-        crate::producer::server::ServerState::new(pool, notify_on_insert).build_router();
+    let producer_routes = crate::producer::server::ServerState::new(
+        pool,
+        notify_on_insert,
+        config.max_submissions_returned,
+    )
+    .build_router();
 
     let routes = Router::new()
         .nest("/producer", producer_routes)