diff --git a/meilidb-data/src/database.rs b/meilidb-data/src/database.rs
index fea4d84d1..ef67227bd 100644
--- a/meilidb-data/src/database.rs
+++ b/meilidb-data/src/database.rs
@@ -19,6 +19,7 @@ use sled::IVec;
 
 use crate::{Schema, SchemaAttr, RankedMap};
 use crate::serde::Deserializer;
+use crate::indexer::Indexer;
 
 #[derive(Debug)]
 pub enum Error {
@@ -240,7 +241,7 @@ impl RawIndex {
         id: DocumentId,
         attr: SchemaAttr,
         value: V,
-    ) -> Result<Option<IVec>, Error>
+    ) -> Result<Option<IVec>, sled::Error>
     where IVec: From<V>,
     {
         let key = document_key(id, attr);
@@ -251,7 +252,7 @@ impl RawIndex {
         &self,
         id: DocumentId,
         attr: SchemaAttr
-    ) -> Result<Option<IVec>, Error>
+    ) -> Result<Option<IVec>, sled::Error>
     {
         let key = document_key(id, attr);
         Ok(self.inner.get(key)?)
@@ -267,7 +268,7 @@ impl RawIndex {
         &self,
         id: DocumentId,
         attr: SchemaAttr
-    ) -> Result<Option<IVec>, Error>
+    ) -> Result<Option<IVec>, sled::Error>
     {
         let key = document_key(id, attr);
         Ok(self.inner.del(key)?)
@@ -358,10 +359,23 @@ impl Index {
     }
 }
 
-pub struct DocumentsAddition(RawIndex);
+pub struct DocumentsAddition {
+    inner: RawIndex,
+    indexer: Indexer,
+}
 
 impl DocumentsAddition {
     pub fn from_raw(inner: RawIndex) -> DocumentsAddition {
+        DocumentsAddition { inner, indexer: Indexer::new() }
+    }
+
+    pub fn update_document<D>(&mut self, document: D) -> Result<(), Error>
+    where D: serde::Serialize,
+    {
+        unimplemented!()
+    }
+
+    pub fn finalize(self) -> sled::Result<()> {
         unimplemented!()
     }
 }
@@ -380,7 +394,7 @@ impl DocumentsDeletion {
         self.documents.push(id);
     }
 
-    pub fn commit(mut self) -> Result<(), Error> {
+    pub fn finalize(mut self) -> Result<(), Error> {
         self.documents.sort_unstable();
         self.documents.dedup();
 
diff --git a/meilidb-data/src/indexer.rs b/meilidb-data/src/indexer.rs
index 82a4ae156..a1be35a93 100644
--- a/meilidb-data/src/indexer.rs
+++ b/meilidb-data/src/indexer.rs
@@ -23,6 +23,13 @@ impl Indexer {
         }
     }
 
+    pub fn with_word_limit(limit: usize) -> Indexer {
+        Indexer {
+            word_limit: limit,
+            indexed: BTreeMap::new(),
+        }
+    }
+
     pub fn index_text(&mut self, id: DocumentId, attr: SchemaAttr, text: &str) {
         for token in Tokenizer::new(text) {
             if token.word_index >= self.word_limit { break }
diff --git a/meilidb-data/src/serde/extract_string.rs b/meilidb-data/src/serde/extract_string.rs
new file mode 100644
index 000000000..9c3ef25e5
--- /dev/null
+++ b/meilidb-data/src/serde/extract_string.rs
@@ -0,0 +1,146 @@
+use serde::Serialize;
+use serde::ser;
+
+use super::SerializerError;
+
+pub struct ExtractString;
+
+impl ser::Serializer for ExtractString {
+    type Ok = String;
+    type Error = SerializerError;
+    type SerializeSeq = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTuple = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTupleStruct = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTupleVariant = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeMap = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeStruct = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeStructVariant = ser::Impossible<Self::Ok, Self::Error>;
+
+    forward_to_unserializable_type! {
+        bool => serialize_bool,
+        char => serialize_char,
+
+        i8  => serialize_i8,
+        i16 => serialize_i16,
+        i32 => serialize_i32,
+        i64 => serialize_i64,
+
+        u8  => serialize_u8,
+        u16 => serialize_u16,
+        u32 => serialize_u32,
+        u64 => serialize_u64,
+
+        f32 => serialize_f32,
+        f64 => serialize_f64,
+    }
+
+    fn serialize_str(self, value: &str) -> Result<Self::Ok, Self::Error> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "&[u8]" })
+    }
+
+    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "Option" })
+    }
+
+    fn serialize_some<T: ?Sized>(self, _value: &T) -> Result<Self::Ok, Self::Error>
+    where T: Serialize,
+    {
+        Err(SerializerError::UnserializableType { name: "Option" })
+    }
+
+    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "()" })
+    }
+
+    fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "unit struct" })
+    }
+
+    fn serialize_unit_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str
+    ) -> Result<Self::Ok, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "unit variant" })
+    }
+
+    fn serialize_newtype_struct<T: ?Sized>(
+        self,
+        _name: &'static str,
+        value: &T
+    ) -> Result<Self::Ok, Self::Error>
+    where T: Serialize,
+    {
+        value.serialize(self)
+    }
+
+    fn serialize_newtype_variant<T: ?Sized>(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _value: &T
+    ) -> Result<Self::Ok, Self::Error>
+    where T: Serialize,
+    {
+        Err(SerializerError::UnserializableType { name: "newtype variant" })
+    }
+
+    fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "sequence" })
+    }
+
+    fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "tuple" })
+    }
+
+    fn serialize_tuple_struct(
+        self,
+        _name: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeTupleStruct, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "tuple struct" })
+    }
+
+    fn serialize_tuple_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeTupleVariant, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "tuple variant" })
+    }
+
+    fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "map" })
+    }
+
+    fn serialize_struct(
+        self,
+        _name: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeStruct, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "struct" })
+    }
+
+    fn serialize_struct_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeStructVariant, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "struct variant" })
+    }
+}
diff --git a/meilidb-data/src/serde/mod.rs b/meilidb-data/src/serde/mod.rs
index beb7660e9..284c970cf 100644
--- a/meilidb-data/src/serde/mod.rs
+++ b/meilidb-data/src/serde/mod.rs
@@ -1,3 +1,73 @@
+macro_rules! forward_to_unserializable_type {
+    ($($ty:ident => $se_method:ident,)*) => {
+        $(
+            fn $se_method(self, _v: $ty) -> Result<Self::Ok, Self::Error> {
+                Err(SerializerError::UnserializableType { name: "$ty" })
+            }
+        )*
+    }
+}
+
 mod deserializer;
+mod serializer;
+mod extract_string;
 
 pub use self::deserializer::Deserializer;
+pub use self::serializer::Serializer;
+pub use self::extract_string::ExtractString;
+
+use std::{fmt, error::Error};
+use rmp_serde::encode::Error as RmpError;
+use serde::ser;
+
+#[derive(Debug)]
+pub enum SerializerError {
+    DocumentIdNotFound,
+    RmpError(RmpError),
+    SledError(sled::Error),
+    UnserializableType { name: &'static str },
+    Custom(String),
+}
+
+impl ser::Error for SerializerError {
+    fn custom<T: fmt::Display>(msg: T) -> Self {
+        SerializerError::Custom(msg.to_string())
+    }
+}
+
+impl fmt::Display for SerializerError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            SerializerError::DocumentIdNotFound => {
+                write!(f, "serialized document does not have an id according to the schema")
+            }
+            SerializerError::RmpError(e) => write!(f, "rmp serde related error: {}", e),
+            SerializerError::SledError(e) => write!(f, "sled related error: {}", e),
+            SerializerError::UnserializableType { name } => {
+                write!(f, "Only struct and map types are considered valid documents and
+                           can be serialized, not {} types directly.", name)
+            },
+            SerializerError::Custom(s) => f.write_str(&s),
+        }
+    }
+}
+
+impl Error for SerializerError {}
+
+impl From<String> for SerializerError {
+    fn from(value: String) -> SerializerError {
+        SerializerError::Custom(value)
+    }
+}
+
+impl From<RmpError> for SerializerError {
+    fn from(error: RmpError) -> SerializerError {
+        SerializerError::RmpError(error)
+    }
+}
+
+impl From<sled::Error> for SerializerError {
+    fn from(error: sled::Error) -> SerializerError {
+        SerializerError::SledError(error)
+    }
+}
diff --git a/meilidb-data/src/serde/serializer.rs b/meilidb-data/src/serde/serializer.rs
new file mode 100644
index 000000000..7a5808cfd
--- /dev/null
+++ b/meilidb-data/src/serde/serializer.rs
@@ -0,0 +1,266 @@
+use std::collections::{HashSet, HashMap};
+use std::fmt;
+use std::error::Error;
+
+use meilidb_core::DocumentId;
+use serde::{de, ser};
+
+use crate::schema::Schema;
+use crate::database::RawIndex;
+use super::{SerializerError, ExtractString};
+
+pub struct Serializer<'a> {
+    pub schema: &'a Schema,
+    pub index: &'a RawIndex,
+    pub document_id: DocumentId,
+}
+
+impl<'a> ser::Serializer for Serializer<'a> {
+    type Ok = ();
+    type Error = SerializerError;
+    type SerializeSeq = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTuple = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTupleStruct = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeTupleVariant = ser::Impossible<Self::Ok, Self::Error>;
+    type SerializeMap = MapSerializer<'a>;
+    type SerializeStruct = StructSerializer<'a>;
+    type SerializeStructVariant = ser::Impossible<Self::Ok, Self::Error>;
+
+    forward_to_unserializable_type! {
+        bool => serialize_bool,
+        char => serialize_char,
+
+        i8  => serialize_i8,
+        i16 => serialize_i16,
+        i32 => serialize_i32,
+        i64 => serialize_i64,
+
+        u8  => serialize_u8,
+        u16 => serialize_u16,
+        u32 => serialize_u32,
+        u64 => serialize_u64,
+
+        f32 => serialize_f32,
+        f64 => serialize_f64,
+    }
+
+    fn serialize_str(self, _v: &str) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "str" })
+    }
+
+    fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "&[u8]" })
+    }
+
+    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "Option" })
+    }
+
+    fn serialize_some<T: ?Sized>(self, _value: &T) -> Result<Self::Ok, Self::Error>
+    where T: ser::Serialize,
+    {
+        Err(SerializerError::UnserializableType { name: "Option" })
+    }
+
+    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "()" })
+    }
+
+    fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "unit struct" })
+    }
+
+    fn serialize_unit_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str
+    ) -> Result<Self::Ok, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "unit variant" })
+    }
+
+    fn serialize_newtype_struct<T: ?Sized>(
+        self,
+        _name: &'static str,
+        value: &T
+    ) -> Result<Self::Ok, Self::Error>
+    where T: ser::Serialize,
+    {
+        value.serialize(self)
+    }
+
+    fn serialize_newtype_variant<T: ?Sized>(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _value: &T
+    ) -> Result<Self::Ok, Self::Error>
+    where T: ser::Serialize,
+    {
+        Err(SerializerError::UnserializableType { name: "newtype variant" })
+    }
+
+    fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "sequence" })
+    }
+
+    fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple, Self::Error> {
+        Err(SerializerError::UnserializableType { name: "tuple" })
+    }
+
+    fn serialize_tuple_struct(
+        self,
+        _name: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeTupleStruct, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "tuple struct" })
+    }
+
+    fn serialize_tuple_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeTupleVariant, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "tuple variant" })
+    }
+
+    fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
+        Ok(MapSerializer {
+            schema: self.schema,
+            document_id: self.document_id,
+            index: self.index,
+            current_key_name: None,
+        })
+    }
+
+    fn serialize_struct(
+        self,
+        _name: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeStruct, Self::Error>
+    {
+        Ok(StructSerializer {
+            schema: self.schema,
+            document_id: self.document_id,
+            index: self.index,
+        })
+    }
+
+    fn serialize_struct_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize
+    ) -> Result<Self::SerializeStructVariant, Self::Error>
+    {
+        Err(SerializerError::UnserializableType { name: "struct variant" })
+    }
+}
+
+pub struct MapSerializer<'a> {
+    pub schema: &'a Schema,
+    pub document_id: DocumentId,
+    pub index: &'a RawIndex,
+    pub current_key_name: Option<String>,
+}
+
+impl<'a> ser::SerializeMap for MapSerializer<'a> {
+    type Ok = ();
+    type Error = SerializerError;
+
+    fn serialize_key<T: ?Sized>(&mut self, key: &T) -> Result<(), Self::Error>
+    where T: ser::Serialize,
+    {
+        let key = key.serialize(ExtractString)?;
+        self.current_key_name = Some(key);
+        Ok(())
+    }
+
+    fn serialize_value<T: ?Sized>(&mut self, value: &T) -> Result<(), Self::Error>
+    where T: ser::Serialize,
+    {
+        let key = self.current_key_name.take().unwrap();
+        self.serialize_entry(&key, value)
+    }
+
+    fn serialize_entry<K: ?Sized, V: ?Sized>(
+        &mut self,
+        key: &K,
+        value: &V,
+    ) -> Result<(), Self::Error>
+    where K: ser::Serialize, V: ser::Serialize,
+    {
+        let key = key.serialize(ExtractString)?;
+
+        serialize_value(
+            self.schema,
+            self.document_id,
+            self.index,
+            &key,
+            value,
+        )
+    }
+
+    fn end(self) -> Result<Self::Ok, Self::Error> {
+        Ok(())
+    }
+}
+
+pub struct StructSerializer<'a> {
+    pub schema: &'a Schema,
+    pub document_id: DocumentId,
+    pub index: &'a RawIndex,
+}
+
+impl<'a> ser::SerializeStruct for StructSerializer<'a> {
+    type Ok = ();
+    type Error = SerializerError;
+
+    fn serialize_field<T: ?Sized>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> Result<(), Self::Error>
+    where T: ser::Serialize,
+    {
+        serialize_value(
+            self.schema,
+            self.document_id,
+            self.index,
+            key,
+            value,
+        )
+    }
+
+    fn end(self) -> Result<Self::Ok, Self::Error> {
+        Ok(())
+    }
+}
+
+fn serialize_value<T: ?Sized>(
+    schema: &Schema,
+    document_id: DocumentId,
+    index: &RawIndex,
+    key: &str,
+    value: &T,
+) -> Result<(), SerializerError>
+where T: ser::Serialize,
+{
+    if let Some(attr) = schema.attribute(key) {
+        let props = schema.props(attr);
+
+        if props.is_stored() {
+            let value = rmp_serde::to_vec_named(value)?;
+            index.set_document_attribute(document_id, attr, value)?;
+        }
+    }
+
+    Ok(())
+}