diff --git a/Cargo.lock b/Cargo.lock
index 989c8a0..7fa0c06 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1671,6 +1671,7 @@ dependencies = [
  "hydrant",
  "miette",
  "serde_json",
+ "tikv-jemallocator",
  "tokio",
  "tracing-subscriber",
 ]
diff --git a/docs/embedding.md b/docs/embedding.md
index ad057b6..037ec2c 100644
--- a/docs/embedding.md
+++ b/docs/embedding.md
@@ -14,6 +14,8 @@ cargo build --release -p hydrant-ffi
 
 this produces the static library `libhydrant_ffi.a` in `target/release` (or `target/<triple>/release` when a target is set). the header is `ffi/include/hydrant.h`.
 
+by default hydrant allocates with the program's own malloc. add `--features alloc-jemalloc` to give it the same tuned jemalloc the binary uses instead. its symbols are prefixed (`_rjem_*`), so only hydrant's allocations move to it and the program's malloc stays as it was.
+
 ## settings
 
 `hydrant_start` takes a json object with the same settings the binary reads from its environment (see [configuration](configuration.md)), plus `RUST_LOG`. the process environment and any `.env` file are ignored, so the embedding program's own environment can't leak in.
diff --git a/ffi/Cargo.toml b/ffi/Cargo.toml
index 6edac16..70237cb 100644
--- a/ffi/Cargo.toml
+++ b/ffi/Cargo.toml
@@ -7,10 +7,19 @@ publish = false
 [lib]
 crate-type = ["staticlib"]
 
+[features]
+# off by default because the embedding program owns the process, allocator included. its
+# symbols are prefixed, so turning it on never swaps out the embedder's own malloc
+alloc-jemalloc = ["dep:tikv-jemallocator"]
+
 [dependencies]
-# no allocator features, because the embedding program owns the process, its allocator included
 hydrant = { path = "..", default-features = false, features = ["indexer", "indexer_stream"] }
 tokio = { version = "1.0", features = ["rt-multi-thread"] }
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 serde_json = "1.0"
 miette = "7"
+tikv-jemallocator = { version = "0.6", optional = true }
+
+[lints.rust]
+# src/allocator.rs is shared with the binary, which has these too
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(feature, values("alloc-mimalloc", "alloc-snmalloc"))'] }
diff --git a/ffi/src/lib.rs b/ffi/src/lib.rs
index 766ef94..eb0b947 100644
--- a/ffi/src/lib.rs
+++ b/ffi/src/lib.rs
@@ -16,6 +16,9 @@ use hydrant::config::Config;
 use hydrant::control::{ApiBinds, Hydrant};
 use hydrant::deps::futures::FutureExt;
 
+#[path = "../../src/allocator.rs"]
+mod allocator;
+
 /// a hydrant started by `hydrant_start`, until `hydrant_free`.
 pub struct HydrantHandle {
     exit: Arc<Exit>,
diff --git a/src/allocator.rs b/src/allocator.rs
index 10f52d3..a9a05f4 100644
--- a/src/allocator.rs
+++ b/src/allocator.rs
@@ -1,5 +1,5 @@
-//! the global allocator, picked by the `alloc-*` features. the hydrant binary and the benches
-//! both include this file, so benchmarks allocate the way production does.
+//! the global allocator, picked by the `alloc-*` features. the hydrant binary, the benches and
+//! hydrant-ffi all include this file, so benchmarks allocate the way production does.
 
 #[cfg(feature = "alloc-mimalloc")]
 #[global_allocator]