diff --git a/milli/src/vector/mod.rs b/milli/src/vector/mod.rs
index 306c1c1e9..d3d05a1c1 100644
--- a/milli/src/vector/mod.rs
+++ b/milli/src/vector/mod.rs
@@ -13,6 +13,7 @@ pub mod error;
 pub mod hf;
 pub mod manual;
 pub mod openai;
+pub mod parsed_vectors;
 pub mod settings;
 
 pub mod ollama;
diff --git a/milli/src/vector/parsed_vectors.rs b/milli/src/vector/parsed_vectors.rs
new file mode 100644
index 000000000..bf4b9ea83
--- /dev/null
+++ b/milli/src/vector/parsed_vectors.rs
@@ -0,0 +1,149 @@
+use std::collections::BTreeMap;
+
+use obkv::KvReader;
+use serde_json::{from_slice, Value};
+
+use super::Embedding;
+use crate::update::del_add::{DelAdd, KvReaderDelAdd};
+use crate::{FieldId, InternalError, UserError};
+
+pub const RESERVED_VECTORS_FIELD_NAME: &str = "_vectors";
+
+#[derive(serde::Serialize, serde::Deserialize, Debug)]
+#[serde(untagged)]
+pub enum Vectors {
+    ImplicitlyUserProvided(VectorOrArrayOfVectors),
+    Explicit(ExplicitVectors),
+}
+
+impl Vectors {
+    pub fn into_array_of_vectors(self) -> Vec<Embedding> {
+        match self {
+            Vectors::ImplicitlyUserProvided(embeddings)
+            | Vectors::Explicit(ExplicitVectors { embeddings, user_provided: _ }) => {
+                embeddings.into_array_of_vectors().unwrap_or_default()
+            }
+        }
+    }
+}
+
+#[derive(serde::Serialize, serde::Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct ExplicitVectors {
+    pub embeddings: VectorOrArrayOfVectors,
+    pub user_provided: bool,
+}
+
+pub struct ParsedVectorsDiff {
+    pub old: Option<BTreeMap<String, Vectors>>,
+    pub new: Option<BTreeMap<String, Vectors>>,
+}
+
+impl ParsedVectorsDiff {
+    pub fn new(
+        documents_diff: KvReader<'_, FieldId>,
+        old_vectors_fid: Option<FieldId>,
+        new_vectors_fid: Option<FieldId>,
+    ) -> Result<Self, Error> {
+        let old = match old_vectors_fid
+            .and_then(|vectors_fid| documents_diff.get(vectors_fid))
+            .map(KvReaderDelAdd::new)
+            .map(|obkv| to_vector_map(obkv, DelAdd::Deletion))
+            .transpose()
+        {
+            Ok(del) => del,
+            // ignore wrong shape for old version of documents, use an empty map in this case
+            Err(Error::InvalidMap(value)) => {
+                tracing::warn!(%value, "Previous version of the `_vectors` field had a wrong shape");
+                Default::default()
+            }
+            Err(error) => {
+                return Err(error);
+            }
+        }
+        .flatten();
+        let new = new_vectors_fid
+            .and_then(|vectors_fid| documents_diff.get(vectors_fid))
+            .map(KvReaderDelAdd::new)
+            .map(|obkv| to_vector_map(obkv, DelAdd::Addition))
+            .transpose()?
+            .flatten();
+        Ok(Self { old, new })
+    }
+
+    pub fn remove(&mut self, embedder_name: &str) -> (Option<Vectors>, Option<Vectors>) {
+        let old = self.old.as_mut().and_then(|old| old.remove(embedder_name));
+        let new = self.new.as_mut().and_then(|new| new.remove(embedder_name));
+        (old, new)
+    }
+}
+
+pub struct ParsedVectors(pub BTreeMap<String, Vectors>);
+
+impl ParsedVectors {
+    pub fn from_bytes(value: &[u8]) -> Result<Self, Error> {
+        let Ok(value) = from_slice(value) else {
+            let value = from_slice(value).map_err(Error::InternalSerdeJson)?;
+            return Err(Error::InvalidMap(value));
+        };
+        Ok(ParsedVectors(value))
+    }
+
+    pub fn retain_user_provided_vectors(&mut self) {
+        self.0.retain(|_k, v| match v {
+            Vectors::ImplicitlyUserProvided(_) => true,
+            Vectors::Explicit(ExplicitVectors { embeddings: _, user_provided }) => *user_provided,
+        });
+    }
+}
+
+pub enum Error {
+    InvalidMap(Value),
+    InternalSerdeJson(serde_json::Error),
+}
+
+impl Error {
+    pub fn to_crate_error(self, document_id: String) -> crate::Error {
+        match self {
+            Error::InvalidMap(value) => {
+                crate::Error::UserError(UserError::InvalidVectorsMapType { document_id, value })
+            }
+            Error::InternalSerdeJson(error) => {
+                crate::Error::InternalError(InternalError::SerdeJson(error))
+            }
+        }
+    }
+}
+
+fn to_vector_map(
+    obkv: KvReaderDelAdd,
+    side: DelAdd,
+) -> Result<Option<BTreeMap<String, Vectors>>, Error> {
+    Ok(if let Some(value) = obkv.get(side) {
+        let ParsedVectors(parsed_vectors) = ParsedVectors::from_bytes(value)?;
+        Some(parsed_vectors)
+    } else {
+        None
+    })
+}
+
+/// Represents either a vector or an array of multiple vectors.
+#[derive(serde::Serialize, serde::Deserialize, Debug)]
+#[serde(transparent)]
+pub struct VectorOrArrayOfVectors {
+    #[serde(with = "either::serde_untagged_optional")]
+    inner: Option<either::Either<Embedding, Vec<Embedding>>>,
+}
+
+impl VectorOrArrayOfVectors {
+    pub fn into_array_of_vectors(self) -> Option<Vec<Embedding>> {
+        match self.inner? {
+            either::Either::Left(vector) => Some(vec![vector]),
+            either::Either::Right(vectors) => Some(vectors),
+        }
+    }
+
+    pub fn from_array_of_vectors(array_of_vec: Vec<Embedding>) -> Self {
+        Self { inner: Some(either::Either::Right(array_of_vec)) }
+    }
+}