diff --git a/http-ui/src/main.rs b/http-ui/src/main.rs
index a29eb8895..2ce7f8bd1 100644
--- a/http-ui/src/main.rs
+++ b/http-ui/src/main.rs
@@ -225,6 +225,7 @@ enum UpdateMeta {
     ClearDocuments,
     Settings(Settings),
     Facets(Facets),
+    WordsPrefixes(WordsPrefixes),
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -275,6 +276,14 @@ struct Facets {
     min_level_size: Option<NonZeroUsize>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+#[serde(rename_all = "camelCase")]
+struct WordsPrefixes {
+    threshold: Option<f64>,
+    max_prefix_length: Option<usize>,
+}
+
 // Any value that is present is considered Some value, including null.
 fn deserialize_some<'de, T, D>(deserializer: D) -> Result<Option<T>, D::Error>
 where T: Deserialize<'de>,
@@ -467,6 +476,21 @@ async fn main() -> anyhow::Result<()> {
                         Ok(()) => wtxn.commit().map_err(Into::into),
                         Err(e) => Err(e.into())
                     }
+                },
+                UpdateMeta::WordsPrefixes(settings) => {
+                    // We must use the write transaction of the update here.
+                    let mut wtxn = index_cloned.write_txn()?;
+                    let mut builder = update_builder.words_prefixes(&mut wtxn, &index_cloned);
+                    if let Some(value) = settings.threshold {
+                        builder.threshold(value);
+                    }
+                    if let Some(value) = settings.max_prefix_length {
+                        builder.max_prefix_length(value);
+                    }
+                    match builder.execute() {
+                        Ok(()) => wtxn.commit().map_err(Into::into),
+                        Err(e) => Err(e.into())
+                    }
                 }
             };
 
@@ -884,6 +908,19 @@ async fn main() -> anyhow::Result<()> {
             warp::reply()
         });
 
+    let update_store_cloned = update_store.clone();
+    let update_status_sender_cloned = update_status_sender.clone();
+    let change_words_prefixes_route = warp::filters::method::post()
+        .and(warp::path!("words-prefixes"))
+        .and(warp::body::json())
+        .map(move |settings: WordsPrefixes| {
+            let meta = UpdateMeta::WordsPrefixes(settings);
+            let update_id = update_store_cloned.register_update(&meta, &[]).unwrap();
+            let _ = update_status_sender_cloned.send(UpdateStatus::Pending { update_id, meta });
+            eprintln!("update {} registered", update_id);
+            warp::reply()
+        });
+
     let update_store_cloned = update_store.clone();
     let update_status_sender_cloned = update_status_sender.clone();
     let abort_update_id_route = warp::filters::method::delete()
@@ -958,6 +995,7 @@ async fn main() -> anyhow::Result<()> {
         .or(clearing_route)
         .or(change_settings_route)
         .or(change_facet_levels_route)
+        .or(change_words_prefixes_route)
         .or(update_ws_route);
 
     let addr = SocketAddr::from_str(&opt.http_listen_addr)?;
diff --git a/milli/src/update/update_builder.rs b/milli/src/update/update_builder.rs
index 8d6eb034d..c966f72d2 100644
--- a/milli/src/update/update_builder.rs
+++ b/milli/src/update/update_builder.rs
@@ -2,7 +2,7 @@ use grenad::CompressionType;
 use rayon::ThreadPool;
 
 use crate::Index;
-use super::{ClearDocuments, DeleteDocuments, IndexDocuments, Settings, Facets};
+use super::{ClearDocuments, DeleteDocuments, IndexDocuments, Settings, Facets, WordsPrefixes};
 
 pub struct UpdateBuilder<'a> {
     pub(crate) log_every_n: Option<usize>,
@@ -135,4 +135,19 @@ impl<'a> UpdateBuilder<'a> {
 
         builder
     }
+
+    pub fn words_prefixes<'t, 'u, 'i>(
+        self,
+        wtxn: &'t mut heed::RwTxn<'i, 'u>,
+        index: &'i Index,
+    ) -> WordsPrefixes<'t, 'u, 'i>
+    {
+        let mut builder = WordsPrefixes::new(wtxn, index, self.update_id);
+
+        builder.chunk_compression_type = self.chunk_compression_type;
+        builder.chunk_compression_level = self.chunk_compression_level;
+        builder.chunk_fusing_shrink_size = self.chunk_fusing_shrink_size;
+
+        builder
+    }
 }