diff --git a/quickwit/quickwit-cli/src/index.rs b/quickwit/quickwit-cli/src/index.rs
index 38fca8a0f1b..1a2e72f0e66 100644
--- a/quickwit/quickwit-cli/src/index.rs
+++ b/quickwit/quickwit-cli/src/index.rs
@@ -28,7 +28,6 @@ use std::time::{Duration, Instant};
 use std::{fmt, io};
 
 use anyhow::{anyhow, bail, Context};
-use bytes::Bytes;
 use bytesize::ByteSize;
 use clap::{arg, Arg, ArgAction, ArgMatches, Command};
 use colored::{ColoredString, Colorize};
@@ -466,6 +465,9 @@ pub async fn create_index_cli(args: CreateIndexArgs) -> anyhow::Result<()> {
     println!("❯ Creating index...");
     let storage_resolver = StorageResolver::unconfigured();
     let file_content = load_file(&storage_resolver, &args.index_config_uri).await?;
+    let index_config_str: String = std::str::from_utf8(&file_content)
+        .with_context(|| format!("Invalid utf8: `{}`", args.index_config_uri))?
+        .to_string();
     let config_format = ConfigFormat::sniff_from_uri(&args.index_config_uri)?;
     let qw_client = args.client_args.client();
     // TODO: nice to have: check first if the index exists by send a GET request, if we get a 404,
@@ -479,10 +481,9 @@ pub async fn create_index_cli(args: CreateIndexArgs) -> anyhow::Result<()> {
             return Ok(());
         }
     }
-    let bytes = Bytes::from(file_content.to_vec());
     qw_client
         .indexes()
-        .create(bytes, config_format, args.overwrite)
+        .create(&index_config_str, config_format, args.overwrite)
         .await?;
     println!("{} Index successfully created.", "✔".color(GREEN_COLOR));
     Ok(())
diff --git a/quickwit/quickwit-cli/src/source.rs b/quickwit/quickwit-cli/src/source.rs
index cecb7586434..175ea7fc4c6 100644
--- a/quickwit/quickwit-cli/src/source.rs
+++ b/quickwit/quickwit-cli/src/source.rs
@@ -20,7 +20,6 @@
 use std::str::FromStr;
 
 use anyhow::{bail, Context};
-use bytes::Bytes;
 use clap::{arg, ArgMatches, Command};
 use colored::Colorize;
 use itertools::Itertools;
@@ -330,11 +329,13 @@ async fn create_source_cli(args: CreateSourceArgs) -> anyhow::Result<()> {
     println!("❯ Creating source...");
     let storage_resolver = StorageResolver::unconfigured();
     let source_config_content = load_file(&storage_resolver, &args.source_config_uri).await?;
+    let source_config_str: &str = std::str::from_utf8(&source_config_content)
+        .with_context(|| format!("source config is not utf-8: {}", args.source_config_uri))?;
     let config_format = ConfigFormat::sniff_from_uri(&args.source_config_uri)?;
     let qw_client = args.client_args.client();
     qw_client
         .sources(&args.index_id)
-        .create(Bytes::from(source_config_content.to_vec()), config_format)
+        .create(source_config_str, config_format)
         .await?;
     println!("{} Source successfully created.", "✔".color(GREEN_COLOR));
     Ok(())
diff --git a/quickwit/quickwit-common/src/rate_limiter.rs b/quickwit/quickwit-common/src/rate_limiter.rs
index ddcb3c1baae..a1e1e2e2d37 100644
--- a/quickwit/quickwit-common/src/rate_limiter.rs
+++ b/quickwit/quickwit-common/src/rate_limiter.rs
@@ -101,6 +101,21 @@ impl RateLimiter {
         }
     }
 
+    /// Acquires some permits from the rate limiter.
+    /// If the permits are not available, returns the duration to wait before trying again.
+    pub fn acquire_with_duration(&mut self, num_permits: u64) -> Result<(), Duration> {
+        if self.acquire_inner(num_permits) {
+            return Ok(());
+        }
+        self.refill(Instant::now());
+        if self.acquire_inner(num_permits) {
+            return Ok(());
+        }
+        let missing = num_permits - self.available_permits;
+        let wait = Duration::from_micros(missing * self.refill_period_micros / self.refill_amount);
+        Err(wait)
+    }
+
     pub fn acquire_bytes(&mut self, bytes: ByteSize) -> bool {
         self.acquire(bytes.as_u64())
     }
diff --git a/quickwit/quickwit-integration-tests/src/test_utils/cluster_sandbox.rs b/quickwit/quickwit-integration-tests/src/test_utils/cluster_sandbox.rs
index 0f1cb22ef59..9466bcbaf32 100644
--- a/quickwit/quickwit-integration-tests/src/test_utils/cluster_sandbox.rs
+++ b/quickwit/quickwit-integration-tests/src/test_utils/cluster_sandbox.rs
@@ -104,7 +104,7 @@ fn transport_url(addr: SocketAddr) -> Url {
 #[macro_export]
 macro_rules! ingest_json {
     ($($json:tt)+) => {
-        quickwit_rest_client::models::IngestSource::Bytes(json!($($json)+).to_string().into())
+        quickwit_rest_client::models::IngestSource::Str(json!($($json)+).to_string())
     };
 }
 
diff --git a/quickwit/quickwit-integration-tests/src/tests/basic_tests.rs b/quickwit/quickwit-integration-tests/src/tests/basic_tests.rs
index 15cb0abc04f..f0264c7368b 100644
--- a/quickwit/quickwit-integration-tests/src/tests/basic_tests.rs
+++ b/quickwit/quickwit-integration-tests/src/tests/basic_tests.rs
@@ -106,8 +106,7 @@ async fn test_standalone_server() {
                   field_mappings:
                   - name: body
                     type: text
-                "#
-                .into(),
+                "#,
                 quickwit_config::ConfigFormat::Yaml,
                 false,
             )
@@ -178,8 +177,7 @@ async fn test_multi_nodes_cluster() {
                 type: text
             indexing_settings:
               commit_timeout_secs: 1
-            "#
-            .into(),
+            "#,
             quickwit_config::ConfigFormat::Yaml,
             false,
         )
diff --git a/quickwit/quickwit-integration-tests/src/tests/index_tests.rs b/quickwit/quickwit-integration-tests/src/tests/index_tests.rs
index 688114cdb98..4eeaf7c53b5 100644
--- a/quickwit/quickwit-integration-tests/src/tests/index_tests.rs
+++ b/quickwit/quickwit-integration-tests/src/tests/index_tests.rs
@@ -20,7 +20,6 @@
 use std::collections::HashSet;
 use std::time::Duration;
 
-use bytes::Bytes;
 use quickwit_common::test_utils::wait_until_predicate;
 use quickwit_config::service::QuickwitService;
 use quickwit_config::ConfigFormat;
@@ -40,7 +39,7 @@ async fn test_restarting_standalone_server() {
     quickwit_common::setup_logging_for_tests();
     let sandbox = ClusterSandbox::start_standalone_node().await.unwrap();
     let index_id = "test-index-with-restarting";
-    let index_config = Bytes::from(format!(
+    let index_config = format!(
         r#"
             version: 0.6
             index_id: {}
@@ -56,7 +55,7 @@ async fn test_restarting_standalone_server() {
                     max_merge_factor: 3
             "#,
         index_id
-    ));
+    );
 
     // Create the index.
     sandbox
@@ -287,7 +286,7 @@ async fn test_ingest_v2_happy_path() {
     sandbox
         .indexer_rest_client
         .indexes()
-        .create(TEST_INDEX_CONFIG.into(), ConfigFormat::Yaml, false)
+        .create(TEST_INDEX_CONFIG, ConfigFormat::Yaml, false)
         .await
         .unwrap();
     sandbox
@@ -330,7 +329,7 @@ async fn test_commit_modes() {
     sandbox
         .indexer_rest_client
         .indexes()
-        .create(TEST_INDEX_CONFIG.into(), ConfigFormat::Yaml, false)
+        .create(TEST_INDEX_CONFIG, ConfigFormat::Yaml, false)
         .await
         .unwrap();
 
@@ -475,8 +474,7 @@ async fn test_very_large_index_name() {
                     - name: body
                       type: text
                 "#,
-            )
-            .into(),
+            ),
             ConfigFormat::Yaml,
             false,
         )
@@ -531,8 +529,7 @@ async fn test_very_large_index_name() {
                         - name: body
                           type: text
                     "#,
-            )
-            .into(),
+            ),
             ConfigFormat::Yaml,
             false,
         )
@@ -568,8 +565,7 @@ async fn test_shutdown() {
                 type: text
             indexing_settings:
               commit_timeout_secs: 1
-            "#
-            .into(),
+            "#,
             ConfigFormat::Yaml,
             false,
         )
diff --git a/quickwit/quickwit-rest-client/src/lib.rs b/quickwit/quickwit-rest-client/src/lib.rs
index 6c6d442d188..12f8faac537 100644
--- a/quickwit/quickwit-rest-client/src/lib.rs
+++ b/quickwit/quickwit-rest-client/src/lib.rs
@@ -29,6 +29,10 @@ pub mod error;
 pub mod models;
 pub mod rest_client;
 
+// re-exports
+pub use quickwit_config::ConfigFormat;
+pub use reqwest::Url;
+
 pub(crate) struct BatchLineReader {
     buf_reader: BufReader<Box<dyn AsyncRead + Send + Sync + Unpin>>,
     buffer: Vec<u8>,
@@ -107,10 +111,11 @@ impl BatchLineReader {
         self.has_next
     }
 
-    fn from_bytes(bytes: Bytes, max_batch_num_bytes: usize) -> Self {
-        use std::io::Cursor;
-
-        Self::new(Box::new(Cursor::new(bytes.to_vec())), max_batch_num_bytes)
+    fn from_string(payload: impl ToString, max_batch_num_bytes: usize) -> Self {
+        Self::new(
+            Box::new(std::io::Cursor::new(payload.to_string().into_bytes())),
+            max_batch_num_bytes,
+        )
     }
 }
 
@@ -121,12 +126,12 @@ mod tests {
     #[tokio::test]
     async fn test_batch_reader() {
         {
-            let mut batch_reader = BatchLineReader::from_bytes("".into(), 10);
+            let mut batch_reader = BatchLineReader::from_string("".to_string(), 10);
             assert!(batch_reader.next_batch().await.unwrap().is_none());
             assert!(batch_reader.next_batch().await.unwrap().is_none());
         }
         {
-            let mut batch_reader = BatchLineReader::from_bytes("foo\n".into(), 10);
+            let mut batch_reader = BatchLineReader::from_string("foo\n", 10);
             assert_eq!(
                 &batch_reader.next_batch().await.unwrap().unwrap()[..],
                 b"foo\n"
@@ -135,7 +140,7 @@ mod tests {
             assert!(batch_reader.next_batch().await.unwrap().is_none());
         }
         {
-            let mut batch_reader = BatchLineReader::from_bytes("foo\nbar\nqux\n".into(), 10);
+            let mut batch_reader = BatchLineReader::from_string("foo\nbar\nqux\n", 10);
             assert_eq!(
                 &batch_reader.next_batch().await.unwrap().unwrap()[..],
                 b"foo\nbar\n"
@@ -148,7 +153,7 @@ mod tests {
             assert!(batch_reader.next_batch().await.unwrap().is_none());
         }
         {
-            let mut batch_reader = BatchLineReader::from_bytes("fooo\nbaar\nqux\n".into(), 10);
+            let mut batch_reader = BatchLineReader::from_string("fooo\nbaar\nqux\n", 10);
             assert_eq!(
                 &batch_reader.next_batch().await.unwrap().unwrap()[..],
                 b"fooo\nbaar\n"
@@ -162,7 +167,7 @@ mod tests {
         }
         {
             let mut batch_reader =
-                BatchLineReader::from_bytes("foobarquxbaz\nfoo\nbar\nqux\n".into(), 10);
+                BatchLineReader::from_string("foobarquxbaz\nfoo\nbar\nqux\n", 10);
             assert_eq!(
                 &batch_reader.next_batch().await.unwrap().unwrap()[..],
                 b"foo\nbar\n"
@@ -176,7 +181,7 @@ mod tests {
         }
         {
             let mut batch_reader =
-                BatchLineReader::from_bytes("foo\nbar\nfoobarquxbaz\nqux\n".into(), 10);
+                BatchLineReader::from_string("foo\nbar\nfoobarquxbaz\nqux\n", 10);
             assert_eq!(
                 &batch_reader.next_batch().await.unwrap().unwrap()[..],
                 b"foo\nbar\n"
diff --git a/quickwit/quickwit-rest-client/src/models.rs b/quickwit/quickwit-rest-client/src/models.rs
index dd1577abd25..4ed8d7d92c9 100644
--- a/quickwit/quickwit-rest-client/src/models.rs
+++ b/quickwit/quickwit-rest-client/src/models.rs
@@ -20,7 +20,6 @@
 use std::path::PathBuf;
 use std::time::Duration;
 
-use bytes::Bytes;
 use reqwest::StatusCode;
 use serde::de::DeserializeOwned;
 
@@ -79,7 +78,7 @@ impl ApiResponse {
 
 #[derive(Clone)]
 pub enum IngestSource {
-    Bytes(Bytes),
+    Str(String),
     File(PathBuf),
     Stdin,
 }
diff --git a/quickwit/quickwit-rest-client/src/rest_client.rs b/quickwit/quickwit-rest-client/src/rest_client.rs
index 6b333131b93..109c0b7c15e 100644
--- a/quickwit/quickwit-rest-client/src/rest_client.rs
+++ b/quickwit/quickwit-rest-client/src/rest_client.rs
@@ -232,11 +232,11 @@ impl QuickwitClient {
         IndexClient::new(&self.transport, self.timeout)
     }
 
-    pub fn splits<'a, 'b: 'a>(&'a self, index_id: &'b str) -> SplitClient {
+    pub fn splits<'a>(&'a self, index_id: &'a str) -> SplitClient {
         SplitClient::new(&self.transport, self.timeout, index_id)
     }
 
-    pub fn sources<'a, 'b: 'a>(&'a self, index_id: &'b str) -> SourceClient {
+    pub fn sources<'a>(&'a self, index_id: &'a str) -> SourceClient {
         SourceClient::new(&self.transport, self.timeout, index_id)
     }
 
@@ -271,7 +271,9 @@ impl QuickwitClient {
                 BatchLineReader::from_file(&filepath, batch_size_limit).await?
             }
             IngestSource::Stdin => BatchLineReader::from_stdin(batch_size_limit),
-            IngestSource::Bytes(bytes) => BatchLineReader::from_bytes(bytes, batch_size_limit),
+            IngestSource::Str(ingest_payload) => {
+                BatchLineReader::from_string(ingest_payload, batch_size_limit)
+            }
         };
         while let Some(batch) = batch_reader.next_batch().await? {
             loop {
@@ -329,11 +331,12 @@ impl<'a> IndexClient<'a> {
 
     pub async fn create(
         &self,
-        body: Bytes,
+        index_config: impl ToString,
         config_format: ConfigFormat,
         overwrite: bool,
     ) -> Result<IndexMetadata, Error> {
         let header_map = header_from_config_format(config_format);
+        let body = Bytes::from(index_config.to_string());
         let response = self
             .transport
             .send(
@@ -449,14 +452,14 @@ impl<'a, 'b> SplitClient<'a, 'b> {
 }
 
 /// Client for source APIs.
-pub struct SourceClient<'a, 'b> {
+pub struct SourceClient<'a> {
     transport: &'a Transport,
     timeout: Timeout,
-    index_id: &'b str,
+    index_id: &'a str,
 }
 
-impl<'a, 'b> SourceClient<'a, 'b> {
-    fn new(transport: &'a Transport, timeout: Timeout, index_id: &'b str) -> Self {
+impl<'a> SourceClient<'a> {
+    fn new(transport: &'a Transport, timeout: Timeout, index_id: &'a str) -> Self {
         Self {
             transport,
             timeout,
@@ -470,10 +473,11 @@ impl<'a, 'b> SourceClient<'a, 'b> {
 
     pub async fn create(
         &self,
-        body: Bytes,
+        source_config_input: impl ToString,
         config_format: ConfigFormat,
     ) -> Result<SourceConfig, Error> {
         let header_map = header_from_config_format(config_format);
+        let source_config_bytes: Bytes = Bytes::from(source_config_input.to_string());
         let response = self
             .transport
             .send::<()>(
@@ -481,7 +485,7 @@ impl<'a, 'b> SourceClient<'a, 'b> {
                 &self.sources_root_url(),
                 Some(header_map),
                 None,
-                Some(body),
+                Some(source_config_bytes),
                 self.timeout,
             )
             .await?;
@@ -651,7 +655,6 @@ mod test {
     use std::path::PathBuf;
     use std::str::FromStr;
 
-    use bytes::Bytes;
     use quickwit_config::{ConfigFormat, SourceConfig};
     use quickwit_indexing::mock_split;
     use quickwit_ingest::CommitType;
@@ -886,7 +889,7 @@ mod test {
             .up_to_n_times(1)
             .mount(&mock_server)
             .await;
-        let post_body = Bytes::from(serde_json::to_vec(&index_config_to_create).unwrap());
+        let post_body = serde_json::to_string(&index_config_to_create).unwrap();
         assert_eq!(
             qw_client
                 .indexes()
@@ -909,7 +912,7 @@ mod test {
         assert_eq!(
             qw_client
                 .indexes()
-                .create(Bytes::from("".as_bytes()), ConfigFormat::Yaml, false)
+                .create("", ConfigFormat::Yaml, false)
                 .await
                 .unwrap(),
             index_metadata
@@ -1044,7 +1047,7 @@ mod test {
         assert_eq!(
             qw_client
                 .sources("my-index")
-                .create(Bytes::from("".as_bytes()), ConfigFormat::Toml)
+                .create("", ConfigFormat::Toml)
                 .await
                 .unwrap(),
             source_config