diff --git a/src/subcommand/serve.rs b/src/subcommand/serve.rs
index 9b2a17ed0..c4965491c 100644
--- a/src/subcommand/serve.rs
+++ b/src/subcommand/serve.rs
@@ -224,8 +224,9 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
                     let mut builder = update_builder.index_documents(&mut wtxn, &index_cloned);
 
                     match format.as_str() {
-                        "json" => builder.update_format(UpdateFormat::Json),
                         "csv" => builder.update_format(UpdateFormat::Csv),
+                        "json" => builder.update_format(UpdateFormat::Json),
+                        "json-stream" => builder.update_format(UpdateFormat::JsonStream),
                         otherwise => panic!("invalid update format {:?}", otherwise),
                     };
 
@@ -491,6 +492,7 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
         let format = match update_format {
             UpdateFormat::Csv => String::from("csv"),
             UpdateFormat::Json => String::from("json"),
+            UpdateFormat::JsonStream => String::from("json-stream"),
         };
 
         let meta = UpdateMeta::DocumentsAddition { method, format };
@@ -540,6 +542,23 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
             )
         });
 
+    let update_store_cloned = update_store.clone();
+    let update_status_sender_cloned = update_status_sender.clone();
+    let indexing_route_json_stream = warp::filters::method::post()
+        .and(warp::path!("documents"))
+        .and(warp::header::exact_ignore_case("content-type", "application/x-ndjson"))
+        .and(warp::filters::query::query())
+        .and(warp::body::stream())
+        .and_then(move |params: QueryUpdate, stream| {
+            buf_stream(
+                update_store_cloned.clone(),
+                update_status_sender_cloned.clone(),
+                params.method,
+                UpdateFormat::JsonStream,
+                stream,
+            )
+        });
+
     let update_status_sender_cloned = update_status_sender.clone();
     let clearing_route = warp::filters::method::post()
         .and(warp::path!("clear-documents"))
@@ -595,6 +614,7 @@ pub fn run(opt: Opt) -> anyhow::Result<()> {
         .or(query_route)
         .or(indexing_route_csv)
         .or(indexing_route_json)
+        .or(indexing_route_json_stream)
         .or(clearing_route)
         .or(update_ws_route);
 
diff --git a/src/update/index_documents/mod.rs b/src/update/index_documents/mod.rs
index 8a1571328..e79190679 100644
--- a/src/update/index_documents/mod.rs
+++ b/src/update/index_documents/mod.rs
@@ -187,6 +187,8 @@ pub enum UpdateFormat {
     Csv,
     /// The given update is a JSON array with documents inside.
     Json,
+    /// The given update is a JSON stream with a document on each line.
+    JsonStream,
 }
 
 pub struct IndexDocuments<'t, 'u, 'i> {
@@ -306,6 +308,7 @@ impl<'t, 'u, 'i> IndexDocuments<'t, 'u, 'i> {
         let output = match self.update_format {
             UpdateFormat::Csv => transform.from_csv(reader)?,
             UpdateFormat::Json => transform.from_json(reader)?,
+            UpdateFormat::JsonStream => transform.from_json_stream(reader)?,
         };
 
         let TransformOutput {
@@ -844,4 +847,30 @@ mod tests {
         assert_eq!(count, 0);
         drop(rtxn);
     }
+
+    #[test]
+    fn json_stream_documents() {
+        let path = tempfile::tempdir().unwrap();
+        let mut options = EnvOpenOptions::new();
+        options.map_size(10 * 1024 * 1024); // 10 MB
+        let index = Index::new(options, &path).unwrap();
+
+        // First we send 3 documents with an id for only one of them.
+        let mut wtxn = index.write_txn().unwrap();
+        let content = &br#"
+        { "name": "kevin" }
+        { "name": "kevina", "id": 21 }
+        { "name": "benoit" }
+        "#[..];
+        let mut builder = IndexDocuments::new(&mut wtxn, &index);
+        builder.update_format(UpdateFormat::JsonStream);
+        builder.execute(content, |_, _| ()).unwrap();
+        wtxn.commit().unwrap();
+
+        // Check that there is 3 documents now.
+        let rtxn = index.read_txn().unwrap();
+        let count = index.number_of_documents(&rtxn).unwrap();
+        assert_eq!(count, 3);
+        drop(rtxn);
+    }
 }
diff --git a/src/update/index_documents/transform.rs b/src/update/index_documents/transform.rs
index 1a4c599eb..3fd7170dd 100644
--- a/src/update/index_documents/transform.rs
+++ b/src/update/index_documents/transform.rs
@@ -2,6 +2,7 @@ use std::borrow::Cow;
 use std::convert::TryFrom;
 use std::fs::File;
 use std::io::{Read, Seek, SeekFrom};
+use std::iter::Peekable;
 
 use anyhow::{anyhow, Context};
 use fst::{IntoStreamer, Streamer};
@@ -24,6 +25,12 @@ pub struct TransformOutput {
     pub documents_file: File,
 }
 
+/// Extract the users ids, deduplicate and compute the new internal documents ids
+/// and fields ids, writing all the documents under their internal ids into a final file.
+///
+/// Outputs the new `FieldsIdsMap`, the new `UsersIdsDocumentsIds` map, the new documents ids,
+/// the replaced documents ids, the number of documents in this update and the file
+/// containing all those documents.
 pub struct Transform<'t, 'i> {
     pub rtxn: &'t heed::RoTxn<'i>,
     pub index: &'i Index,
@@ -37,26 +44,41 @@ pub struct Transform<'t, 'i> {
 }
 
 impl Transform<'_, '_> {
-    /// Extract the users ids, deduplicate and compute the new internal documents ids
-    /// and fields ids, writing all the documents under their internal ids into a final file.
-    ///
-    /// Outputs the new `FieldsIdsMap`, the new `UsersIdsDocumentsIds` map, the new documents ids,
-    /// the replaced documents ids, the number of documents in this update and the file
-    /// containing all those documents.
     pub fn from_json<R: Read>(self, reader: R) -> anyhow::Result<TransformOutput> {
+        self.from_generic_json(reader, false)
+    }
+
+    pub fn from_json_stream<R: Read>(self, reader: R) -> anyhow::Result<TransformOutput> {
+        self.from_generic_json(reader, true)
+    }
+
+    fn from_generic_json<R: Read>(self, reader: R, is_stream: bool) -> anyhow::Result<TransformOutput> {
         let mut fields_ids_map = self.index.fields_ids_map(self.rtxn)?;
         let users_ids_documents_ids = self.index.users_ids_documents_ids(self.rtxn).unwrap();
         let primary_key = self.index.primary_key(self.rtxn)?;
 
         // Deserialize the whole batch of documents in memory.
-        let documents: Vec<Map<String, Value>> = serde_json::from_reader(reader)?;
+        let mut documents: Peekable<Box<dyn Iterator<Item=serde_json::Result<Map<String, Value>>>>> = if is_stream {
+            let iter = serde_json::Deserializer::from_reader(reader).into_iter();
+            let iter = Box::new(iter) as Box<dyn Iterator<Item=_>>;
+            iter.peekable()
+        } else {
+            let vec: Vec<_> = serde_json::from_reader(reader)?;
+            let iter = vec.into_iter().map(Ok);
+            let iter = Box::new(iter) as Box<dyn Iterator<Item=_>>;
+            iter.peekable()
+        };
 
         // We extract the primary key from the first document in
         // the batch if it hasn't already been defined in the index.
         let primary_key = match primary_key {
             Some(primary_key) => primary_key,
             None => {
-                match documents.get(0).and_then(|doc| doc.keys().find(|k| k.contains("id"))) {
+                // We ignore a potential error here as we can't early return it now,
+                // the peek method gives us only a reference on the next item,
+                // we will eventually return it in the iteration just after.
+                let first = documents.peek().and_then(|r| r.as_ref().ok());
+                match first.and_then(|doc| doc.keys().find(|k| k.contains("id"))) {
                     Some(key) => fields_ids_map.insert(&key).context("field id limit reached")?,
                     None => {
                         if !self.autogenerate_docids {
@@ -70,7 +92,7 @@ impl Transform<'_, '_> {
             },
         };
 
-        if documents.is_empty() {
+        if documents.peek().is_none() {
             return Ok(TransformOutput {
                 primary_key,
                 fields_ids_map,
@@ -110,7 +132,9 @@ impl Transform<'_, '_> {
         let mut obkv_buffer = Vec::new();
         let mut uuid_buffer = [0; uuid::adapter::Hyphenated::LENGTH];
 
-        for mut document in documents {
+        for result in documents {
+            let mut document = result?;
+
             obkv_buffer.clear();
             let mut writer = obkv::KvWriter::new(&mut obkv_buffer);
 
@@ -155,12 +179,6 @@ impl Transform<'_, '_> {
         self.from_sorter(sorter, primary_key, fields_ids_map, users_ids_documents_ids)
     }
 
-    /// Extract the users ids, deduplicate and compute the new internal documents ids
-    /// and fields ids, writing all the documents under their internal ids into a final file.
-    ///
-    /// Outputs the new `FieldsIdsMap`, the new `UsersIdsDocumentsIds` map, the new documents ids,
-    /// the replaced documents ids, the number of documents in this update and the file
-    /// containing all those documents.
     pub fn from_csv<R: Read>(self, reader: R) -> anyhow::Result<TransformOutput> {
         let mut fields_ids_map = self.index.fields_ids_map(self.rtxn)?;
         let users_ids_documents_ids = self.index.users_ids_documents_ids(self.rtxn).unwrap();
@@ -261,8 +279,8 @@ impl Transform<'_, '_> {
         self.from_sorter(sorter, primary_key_field_id, fields_ids_map, users_ids_documents_ids)
     }
 
-    /// Generate the TransformOutput based on the given sorter that can be generated from any
-    /// format like CSV, JSON or JSON lines. This sorter must contain a key that is the document
+    /// Generate the `TransformOutput` based on the given sorter that can be generated from any
+    /// format like CSV, JSON or JSON stream. This sorter must contain a key that is the document
     /// id for the user side and the value must be an obkv where keys are valid fields ids.
     fn from_sorter(
         self,