diff --git a/.github/workflows/server-tests.yaml b/.github/workflows/server-tests.yaml
new file mode 100644
index 00000000..5bb4653a
--- /dev/null
+++ b/.github/workflows/server-tests.yaml
@@ -0,0 +1,30 @@
+name: Server Tests
+
+on:
+  pull_request:
+    paths:
+      - "server/**"
+      - "proto/**"
+
+jobs:
+  run_tests:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python
+        uses: actions/setup-python@v1
+        with:
+          python-version: 3.9
+      - name: Loading cache.
+        uses: actions/cache@v2
+        id: model_cache
+        with:
+          path: ~/.cache/huggingface/
+          key: models
+      - name: Install server dependencies
+        run: |
+          make install-server
+      - name: Run tests
+        run: |
+          pip install pytest
+          pytest -sv server/tests
diff --git a/README.md b/README.md
index 92879707..8496ce8f 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@ to power Bloom, BloomZ and MT0-XXL api-inference widgets.
 - 45ms per token generation for BLOOM with 8xA100 80GB
 - Logits warpers (temperature scaling, topk ...)
 - Stop sequences
+- Log probabilities
 
 ## Officially supported models
 
diff --git a/proto/generate.proto b/proto/generate.proto
index 0c67de03..16539f8b 100644
--- a/proto/generate.proto
+++ b/proto/generate.proto
@@ -27,7 +27,7 @@ message ClearCacheRequest {}
 /// Empty response
 message ClearCacheResponse {}
 
-message LogitsWarperParameters {
+message NextTokenChooserParameters {
     /// exponential scaling output probability distribution
     float temperature = 1;
     /// restricting to the k highest probability elements
@@ -52,8 +52,8 @@ message Request {
     string inputs = 2;
     /// The number of tokens inside inputs
     uint32 input_length = 3;
-    /// Logits Warper Parameters
-    LogitsWarperParameters parameters = 4;
+    /// Next Token Chooser Parameters
+    NextTokenChooserParameters parameters = 4;
     /// Stopping Criteria Parameters
     StoppingCriteriaParameters stopping_parameters = 5;
 }
@@ -71,11 +71,17 @@ message GeneratedText {
     /// Request
     Request request = 1;
     /// Output
-    string output = 2;
+    string output_text = 2;
     /// Number of generated tokens
-    uint32 tokens = 3;
+    uint32 generated_tokens = 3;
+    /// Tokens
+    repeated string tokens = 4;
+    /// Token IDs
+    repeated uint32 token_ids = 5;
+    /// Logprobs
+    repeated float logprobs = 6;
     /// Finish reason
-    string finish_reason = 4;
+    string finish_reason = 7;
 }
 
 message GenerateRequest {
diff --git a/router/client/src/lib.rs b/router/client/src/lib.rs
index ae337dd6..295b009b 100644
--- a/router/client/src/lib.rs
+++ b/router/client/src/lib.rs
@@ -7,7 +7,7 @@ mod sharded_client;
 
 pub use client::Client;
 pub use pb::generate::v1::{
-    Batch, GeneratedText, LogitsWarperParameters, Request, StoppingCriteriaParameters,
+    Batch, GeneratedText, NextTokenChooserParameters, Request, StoppingCriteriaParameters,
 };
 pub use sharded_client::ShardedClient;
 use thiserror::Error;
diff --git a/router/src/batcher.rs b/router/src/batcher.rs
index a72a6e44..1484434c 100644
--- a/router/src/batcher.rs
+++ b/router/src/batcher.rs
@@ -187,9 +187,13 @@ fn send_generated(finished: Vec<GeneratedText>, db: &Db) {
         let entry = db
             .remove(&output.request.unwrap().id)
             .expect("ID not found in db. This is a bug.");
+
         let response = InferResponse {
-            output: output.output,
+            output_text: output.output_text,
+            generated_tokens: output.generated_tokens,
+            token_ids: output.token_ids,
             tokens: output.tokens,
+            logprobs: output.logprobs,
             finish_reason: output.finish_reason,
             queued: entry.time,
             start: entry.batch_time.unwrap(), // unwrap is always valid
@@ -202,8 +206,11 @@ fn send_generated(finished: Vec<GeneratedText>, db: &Db) {
 
 #[derive(Debug)]
 pub(crate) struct InferResponse {
-    pub(crate) output: String,
-    pub(crate) tokens: u32,
+    pub(crate) output_text: String,
+    pub(crate) generated_tokens: u32,
+    pub(crate) token_ids: Vec<u32>,
+    pub(crate) tokens: Vec<String>,
+    pub(crate) logprobs: Vec<f32>,
     pub(crate) finish_reason: String,
     pub(crate) queued: Instant,
     pub(crate) start: Instant,
diff --git a/router/src/db.rs b/router/src/db.rs
index 24fb7a09..df9f2b8e 100644
--- a/router/src/db.rs
+++ b/router/src/db.rs
@@ -5,7 +5,7 @@ use parking_lot::Mutex;
 use std::collections::BTreeMap;
 use std::sync::Arc;
 use text_generation_client::{
-    Batch, ClientError, LogitsWarperParameters, Request, StoppingCriteriaParameters,
+    Batch, ClientError, NextTokenChooserParameters, Request, StoppingCriteriaParameters,
 };
 use tokio::sync::oneshot::Sender;
 use tokio::time::Instant;
@@ -71,7 +71,7 @@ impl State {
                 id: *id,
                 inputs: entry.request.inputs.clone(),
                 input_length: entry.input_length as u32,
-                parameters: Some(LogitsWarperParameters::from(
+                parameters: Some(NextTokenChooserParameters::from(
                     entry.request.parameters.clone(),
                 )),
                 stopping_parameters: Some(StoppingCriteriaParameters::from(
@@ -162,7 +162,7 @@ impl Db {
     }
 }
 
-impl From<GenerateParameters> for LogitsWarperParameters {
+impl From<GenerateParameters> for NextTokenChooserParameters {
     fn from(parameters: GenerateParameters) -> Self {
         Self {
             temperature: parameters.temperature,
diff --git a/router/src/lib.rs b/router/src/lib.rs
index b6c694ee..03711580 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -21,7 +21,10 @@ pub(crate) struct GenerateParameters {
     pub do_sample: bool,
     #[serde(default = "default_max_new_tokens")]
     pub max_new_tokens: u32,
+    #[serde(default)]
     pub stop: Vec<String>,
+    #[serde(default)]
+    pub details: bool,
 }
 
 fn default_temperature() -> f32 {
@@ -52,6 +55,7 @@ fn default_parameters() -> GenerateParameters {
         do_sample: default_do_sample(),
         max_new_tokens: default_max_new_tokens(),
         stop: vec![],
+        details: false,
     }
 }
 
@@ -62,10 +66,18 @@ pub(crate) struct GenerateRequest {
     pub parameters: GenerateParameters,
 }
 
+#[derive(Serialize)]
+pub(crate) struct Details {
+    pub finish_reason: String,
+    pub generated_tokens: u32,
+    pub tokens: Vec<(u32, String, f32)>,
+}
+
 #[derive(Serialize)]
 pub(crate) struct GeneratedText {
     pub generated_text: String,
-    pub finish_reason: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub details: Option<Details>,
 }
 
 #[derive(Serialize)]
diff --git a/router/src/server.rs b/router/src/server.rs
index 59296269..2e6c473f 100644
--- a/router/src/server.rs
+++ b/router/src/server.rs
@@ -1,5 +1,5 @@
 use crate::{
-    Batcher, ErrorResponse, GenerateParameters, GenerateRequest, GeneratedText, Validation,
+    Batcher, Details, ErrorResponse, GenerateParameters, GenerateRequest, GeneratedText, Validation,
 };
 use axum::extract::Extension;
 use axum::http::{HeaderMap, StatusCode};
@@ -54,6 +54,7 @@ async fn health(state: Extension<ServerState>) -> Result<(), (StatusCode, Json<E
                     do_sample: false,
                     max_new_tokens: 1,
                     stop: vec![],
+                    details: false,
                 },
             },
         )
@@ -89,6 +90,7 @@ async fn generate(
     })?;
 
     // Validate request
+    let details = req.0.parameters.details;
     let (input_length, validated_request) =
         state.validation.validate(req.0).await.map_err(|err| {
             tracing::error!("{}", err.to_string());
@@ -105,12 +107,31 @@ async fn generate(
             err
         })?;
 
+    // Token details
+    let details = match details {
+        true => {
+            let tokens = response
+                .token_ids
+                .into_iter()
+                .zip(response.tokens.into_iter())
+                .zip(response.logprobs.into_iter())
+                .map(|((id, text), logprob)| (id, text, logprob))
+                .collect();
+            Some(Details {
+                finish_reason: response.finish_reason,
+                generated_tokens: response.generated_tokens,
+                tokens,
+            })
+        }
+        false => None,
+    };
+
     // Timings
     let total_time = start_time.elapsed();
     let validation_time = response.queued - start_time;
     let queue_time = response.start - response.queued;
     let inference_time = response.end - response.start;
-    let time_per_token = inference_time / response.tokens;
+    let time_per_token = inference_time / response.generated_tokens;
 
     // Headers
     let mut headers = HeaderMap::new();
@@ -141,12 +162,12 @@ async fn generate(
     tracing::Span::current().record("queue_time", format!("{:?}", queue_time));
     tracing::Span::current().record("inference_time", format!("{:?}", inference_time));
     tracing::Span::current().record("time_per_token", format!("{:?}", time_per_token));
-    tracing::info!("Output: {}", response.output);
+    tracing::info!("Output: {}", response.output_text);
 
     // Send response
     let response = vec![GeneratedText {
-        generated_text: response.output,
-        finish_reason: response.finish_reason,
+        generated_text: response.output_text,
+        details,
     }];
     Ok((headers, Json(response)))
 }
diff --git a/server/tests/conftest.py b/server/tests/conftest.py
index 24cdafac..eb72b8a2 100644
--- a/server/tests/conftest.py
+++ b/server/tests/conftest.py
@@ -7,7 +7,7 @@ from text_generation.pb import generate_pb2
 
 @pytest.fixture
 def default_pb_parameters():
-    return generate_pb2.LogitsWarperParameters(
+    return generate_pb2.NextTokenChooserParameters(
         temperature=1.0,
         top_k=0,
         top_p=1.0,
diff --git a/server/tests/models/test_bloom.py b/server/tests/models/test_bloom.py
index c5dbaa3e..2a6e670e 100644
--- a/server/tests/models/test_bloom.py
+++ b/server/tests/models/test_bloom.py
@@ -128,10 +128,12 @@ def test_causal_lm_generate_token_completion(default_bloom, default_bloom_batch)
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTestTestTestTestTestTest"
+    assert (
+        generated_texts[0].output_text == "TestTestTestTestTestTestTestTestTestTestTest"
+    )
     assert generated_texts[0].request == default_bloom_batch.requests[0]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_bloom_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -151,10 +153,10 @@ def test_causal_lm_generate_token_completion_multi(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTest"
+    assert generated_texts[0].output_text == "TestTestTestTestTestTest"
     assert generated_texts[0].request == default_multi_requests_bloom_batch.requests[1]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_bloom_batch.stopping_criterias[1].max_new_tokens
     )
 
@@ -170,10 +172,12 @@ def test_causal_lm_generate_token_completion_multi(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTestTestTestTestTestTest"
+    assert (
+        generated_texts[0].output_text == "TestTestTestTestTestTestTestTestTestTestTest"
+    )
     assert generated_texts[0].request == default_multi_requests_bloom_batch.requests[0]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_bloom_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -240,10 +244,10 @@ def test_batch_concatenate(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTest"
+    assert generated_texts[0].output_text == "TestTestTestTestTestTest"
     assert generated_texts[0].request == default_multi_requests_bloom_batch.requests[1]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_bloom_batch.stopping_criterias[1].max_new_tokens
     )
 
@@ -259,10 +263,12 @@ def test_batch_concatenate(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTestTestTestTestTestTest"
+    assert (
+        generated_texts[0].output_text == "TestTestTestTestTestTestTestTestTestTestTest"
+    )
     assert generated_texts[0].request == default_bloom_batch.requests[0]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_bloom_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -279,9 +285,11 @@ def test_batch_concatenate(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "TestTestTestTestTestTestTestTestTestTestTest"
+    assert (
+        generated_texts[0].output_text == "TestTestTestTestTestTestTestTestTestTestTest"
+    )
     assert generated_texts[0].request == default_multi_requests_bloom_batch.requests[0]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_bloom_batch.stopping_criterias[0].max_new_tokens
     )
diff --git a/server/tests/models/test_causal_lm.py b/server/tests/models/test_causal_lm.py
index f38776cc..683d9fdd 100644
--- a/server/tests/models/test_causal_lm.py
+++ b/server/tests/models/test_causal_lm.py
@@ -127,10 +127,11 @@ def test_causal_lm_generate_token_completion(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784) at net.minecraft."
+    assert generated_texts[0].output_text == "Test.java:784) at net.minecraft."
     assert generated_texts[0].request == default_causal_lm_batch.requests[0]
+    assert len(generated_texts[0].tokens) == len(generated_texts[0].logprobs)
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_causal_lm_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -150,12 +151,12 @@ def test_causal_lm_generate_token_completion_multi(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784)"
+    assert generated_texts[0].output_text == "Test.java:784)"
     assert (
         generated_texts[0].request == default_multi_requests_causal_lm_batch.requests[1]
     )
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_causal_lm_batch.stopping_criterias[1].max_new_tokens
     )
 
@@ -171,12 +172,12 @@ def test_causal_lm_generate_token_completion_multi(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784) at net.minecraft."
+    assert generated_texts[0].output_text == "Test.java:784) at net.minecraft."
     assert (
         generated_texts[0].request == default_multi_requests_causal_lm_batch.requests[0]
     )
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_causal_lm_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -242,12 +243,12 @@ def test_batch_concatenate(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784)"
+    assert generated_texts[0].output_text == "Test.java:784)"
     assert (
         generated_texts[0].request == default_multi_requests_causal_lm_batch.requests[1]
     )
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_causal_lm_batch.stopping_criterias[1].max_new_tokens
     )
 
@@ -263,10 +264,10 @@ def test_batch_concatenate(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784) at net.minecraft."
+    assert generated_texts[0].output_text == "Test.java:784) at net.minecraft."
     assert generated_texts[0].request == default_causal_lm_batch.requests[0]
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_causal_lm_batch.stopping_criterias[0].max_new_tokens
     )
 
@@ -283,11 +284,11 @@ def test_batch_concatenate(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "Test.java:784) at net.minecraft."
+    assert generated_texts[0].output_text == "Test.java:784) at net.minecraft."
     assert (
         generated_texts[0].request == default_multi_requests_causal_lm_batch.requests[0]
     )
     assert (
-        generated_texts[0].tokens
+        generated_texts[0].generated_tokens
         == default_multi_requests_causal_lm_batch.stopping_criterias[0].max_new_tokens
     )
diff --git a/server/tests/models/test_seq2seq_lm.py b/server/tests/models/test_seq2seq_lm.py
index 94ec70d5..f1b11bc2 100644
--- a/server/tests/models/test_seq2seq_lm.py
+++ b/server/tests/models/test_seq2seq_lm.py
@@ -148,9 +148,9 @@ def test_seq2seq_lm_generate_token_completion(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few weeks"
+    assert generated_texts[0].output_text == "a few weeks"
     assert generated_texts[0].request == default_seq2seq_lm_batch.requests[0]
-    assert generated_texts[0].tokens == 7
+    assert generated_texts[0].generated_tokens == 7
 
 
 def test_seq2seq_lm_generate_token_completion_multi(
@@ -166,12 +166,12 @@ def test_seq2seq_lm_generate_token_completion_multi(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few "
+    assert generated_texts[0].output_text == "a few "
     assert (
         generated_texts[0].request
         == default_multi_requests_seq2seq_lm_batch.requests[1]
     )
-    assert generated_texts[0].tokens == 5
+    assert generated_texts[0].generated_tokens == 5
 
     generated_texts, next_batch = default_seq2seq_lm.generate_token(next_batch)
     assert generated_texts == []
@@ -180,12 +180,12 @@ def test_seq2seq_lm_generate_token_completion_multi(
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few weeks"
+    assert generated_texts[0].output_text == "a few weeks"
     assert (
         generated_texts[0].request
         == default_multi_requests_seq2seq_lm_batch.requests[0]
     )
-    assert generated_texts[0].tokens == 7
+    assert generated_texts[0].generated_tokens == 7
 
 
 def test_batch_concatenate(
@@ -287,28 +287,28 @@ def test_batch_concatenate(
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few "
+    assert generated_texts[0].output_text == "a few "
     assert (
         generated_texts[0].request
         == default_multi_requests_seq2seq_lm_batch.requests[1]
     )
-    assert generated_texts[0].tokens == 5
+    assert generated_texts[0].generated_tokens == 5
 
     generated_texts, next_batch = default_seq2seq_lm.generate_token(next_batch)
     assert next_batch is not None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few weeks"
+    assert generated_texts[0].output_text == "a few weeks"
     assert generated_texts[0].request == default_seq2seq_lm_batch.requests[0]
-    assert generated_texts[0].tokens == 7
+    assert generated_texts[0].generated_tokens == 7
 
     generated_texts, next_batch = default_seq2seq_lm.generate_token(next_batch)
     assert next_batch is None
 
     assert len(generated_texts) == 1
-    assert generated_texts[0].output == "a few weeks"
+    assert generated_texts[0].output_text == "a few weeks"
     assert (
         generated_texts[0].request
         == default_multi_requests_seq2seq_lm_batch.requests[0]
     )
-    assert generated_texts[0].tokens == 7
+    assert generated_texts[0].generated_tokens == 7
diff --git a/server/text_generation/models/bloom.py b/server/text_generation/models/bloom.py
index 20e26419..3561a8ea 100644
--- a/server/text_generation/models/bloom.py
+++ b/server/text_generation/models/bloom.py
@@ -246,12 +246,8 @@ class BLOOMSharded(BLOOM):
         )
 
         # Logits are sharded, so we need to gather them
-        logits_shard = outputs.logits[:, -1, :].contiguous()
-
-        batch_size, vocab_shard_size = logits_shard.shape
-        vocab_size = self.world_size * vocab_shard_size
-        logits = [torch.empty_like(logits_shard) for _ in range(self.world_size)]
-        torch.distributed.all_gather(logits, logits_shard, group=self.process_group)
-        logits = torch.cat(logits, dim=1).view(batch_size, 1, vocab_size)
+        logits = [torch.empty_like(outputs.logits) for _ in range(self.world_size)]
+        torch.distributed.all_gather(logits, outputs.logits, group=self.process_group)
+        logits = torch.cat(logits, dim=2)
 
         return logits, outputs.past_key_values
diff --git a/server/text_generation/models/causal_lm.py b/server/text_generation/models/causal_lm.py
index 72095858..5d62137f 100644
--- a/server/text_generation/models/causal_lm.py
+++ b/server/text_generation/models/causal_lm.py
@@ -22,6 +22,7 @@ class CausalLMBatch:
 
     # All tokens
     all_input_ids: List[torch.Tensor]
+    all_logprobs: List[Optional[torch.Tensor]]
 
     # Lengths of all generations present in the batch
     input_lengths: List[int]
@@ -52,6 +53,7 @@ class CausalLMBatch:
         next_token_choosers = []
         stopping_criterias = []
         input_lengths = []
+        all_logprobs = []
 
         # Parse batch
         for r in pb.requests:
@@ -61,6 +63,7 @@ class CausalLMBatch:
             stopping_criterias.append(
                 StoppingCriteria.from_pb(r.stopping_parameters, tokenizer)
             )
+            all_logprobs.append(None)
 
         pad_to_multiple_of = 8 if "gpu" in str(device) else None
         tokenized_inputs = tokenizer(
@@ -78,6 +81,7 @@ class CausalLMBatch:
             attention_mask=tokenized_inputs["attention_mask"],
             past_key_values=None,
             all_input_ids=all_input_ids,
+            all_logprobs=all_logprobs,
             input_lengths=input_lengths,
             next_token_choosers=next_token_choosers,
             stopping_criterias=stopping_criterias,
@@ -95,6 +99,7 @@ class CausalLMBatch:
         requests = []
         input_lengths = []
         all_input_ids = []
+        all_logprobs = []
         next_token_choosers = []
         stopping_criterias = []
 
@@ -110,6 +115,7 @@ class CausalLMBatch:
             requests.extend(batch.requests)
             input_lengths.extend(batch.input_lengths)
             all_input_ids.extend(batch.all_input_ids)
+            all_logprobs.extend(batch.all_logprobs)
             next_token_choosers.extend(batch.next_token_choosers)
             stopping_criterias.extend(batch.stopping_criterias)
 
@@ -217,6 +223,7 @@ class CausalLMBatch:
             attention_mask=attention_mask,
             past_key_values=past_key_values,
             all_input_ids=all_input_ids,
+            all_logprobs=all_logprobs,
             input_lengths=input_lengths,
             next_token_choosers=next_token_choosers,
             stopping_criterias=stopping_criterias,
@@ -291,6 +298,7 @@ class CausalLM(Model):
         next_batch_input_lengths = []
         next_batch_input_ids = []
         next_batch_all_input_ids = []
+        next_batch_all_logprobs = []
 
         # Metadata
         next_batch_size = 0
@@ -307,6 +315,7 @@ class CausalLM(Model):
             batch.next_token_choosers,
             batch.stopping_criterias,
             batch.all_input_ids,
+            batch.all_logprobs,
         )
 
         # For each member of the batch
@@ -316,34 +325,59 @@ class CausalLM(Model):
             logits,
             next_token_chooser,
             stopping_criteria,
-            all_tokens,
+            all_input_ids,
+            all_logprobs,
         ) in enumerate(iterator):
             # Select next token
-            next_token = next_token_chooser(all_tokens, logits.unsqueeze(0)[:, -1])
+            tokens, logprobs = next_token_chooser(all_input_ids, logits)
+            next_token = tokens[-1].view(1, 1)
 
             # Append next token to all tokens
-            all_tokens = torch.cat([all_tokens, next_token])
+            all_input_ids = torch.cat([all_input_ids, next_token])
+            new_input_length = input_length + 1
+
+            if all_logprobs is None:
+                # logprobs of all prompt tokens (except the first one) and the generated token
+                all_logprobs = logprobs.gather(1, all_input_ids[1:])
+            else:
+                # logprob of the generated token
+                next_token_logprob = logprobs[-1, next_token]
+                all_logprobs = torch.cat([all_logprobs, next_token_logprob])
 
             # Evaluate stopping criteria
-            stop, reason = stopping_criteria(all_tokens)
+            stop, reason = stopping_criteria(all_input_ids)
             if stop:
                 # Decode all tokens
-                output = self.tokenizer.decode(
-                    all_tokens.squeeze(-1), skip_special_tokens=True
+                output_text = self.tokenizer.decode(
+                    all_input_ids.squeeze(-1), skip_special_tokens=True
                 )
+                # Slice with input_length to remove padding
+                token_ids = all_input_ids[-new_input_length:]
+                tokens = self.tokenizer.batch_decode(token_ids)
+                # Add NaN for the first prompt token
+                logprobs = [float("nan")] + all_logprobs[-new_input_length:].squeeze(
+                    1
+                ).tolist()
+
                 # Add to the list of finished generations with the original request
                 generated_texts.append(
                     GeneratedText(
-                        request, output, stopping_criteria.current_tokens, reason
+                        request=request,
+                        output_text=output_text,
+                        generated_tokens=stopping_criteria.current_tokens,
+                        tokens=tokens,
+                        token_ids=token_ids.squeeze(1).tolist(),
+                        logprobs=logprobs,
+                        reason=reason,
                     )
                 )
             # add to the next batch
             else:
                 next_batch_keep_indices.append(i)
                 next_batch_input_ids.append(next_token)
-                next_batch_all_input_ids.append(all_tokens)
+                next_batch_all_input_ids.append(all_input_ids)
+                next_batch_all_logprobs.append(all_logprobs)
                 next_batch_size += 1
-                new_input_length = input_length + 1
                 next_batch_input_lengths.append(new_input_length)
                 next_batch_max_sequence_length = max(
                     next_batch_max_sequence_length, new_input_length
@@ -397,6 +431,7 @@ class CausalLM(Model):
             attention_mask=next_batch_attention_mask,
             past_key_values=next_batch_past_key_values,
             all_input_ids=next_batch_all_input_ids,
+            all_logprobs=next_batch_all_logprobs,
             input_lengths=next_batch_input_lengths,
             next_token_choosers=next_batch_next_token_choosers,
             stopping_criterias=next_batch_stopping_criterias,
diff --git a/server/text_generation/models/galactica.py b/server/text_generation/models/galactica.py
index 680ea43e..a713e69e 100644
--- a/server/text_generation/models/galactica.py
+++ b/server/text_generation/models/galactica.py
@@ -321,12 +321,8 @@ class GalacticaSharded(Galactica):
         )
 
         # Logits are sharded, so we need to gather them
-        logits_shard = outputs.logits[:, -1, :].contiguous()
-
-        batch_size, vocab_shard_size = logits_shard.shape
-        vocab_size = self.world_size * vocab_shard_size
-        logits = [torch.empty_like(logits_shard) for _ in range(self.world_size)]
-        torch.distributed.all_gather(logits, logits_shard, group=self.process_group)
-        logits = torch.cat(logits, dim=1).view(batch_size, 1, vocab_size)
+        logits = [torch.empty_like(outputs.logits) for _ in range(self.world_size)]
+        torch.distributed.all_gather(logits, outputs.logits, group=self.process_group)
+        logits = torch.cat(logits, dim=2)
 
         return logits, outputs.past_key_values
diff --git a/server/text_generation/models/seq2seq_lm.py b/server/text_generation/models/seq2seq_lm.py
index 93e31b4a..e51ce60b 100644
--- a/server/text_generation/models/seq2seq_lm.py
+++ b/server/text_generation/models/seq2seq_lm.py
@@ -30,6 +30,7 @@ class Seq2SeqLMBatch:
     # Lengths of all generations present in the batch
     input_lengths: List[int]
     decoder_input_lengths: List[int]
+    decoder_logprobs: List[Optional[torch.Tensor]]
 
     # Generation helpers
     next_token_choosers: List[NextTokenChooser]
@@ -60,6 +61,7 @@ class Seq2SeqLMBatch:
 
         decoder_input_ids = []
         decoder_input_lengths = []
+        decoder_logprobs = []
 
         # Parse batch
         for r in pb.requests:
@@ -72,6 +74,7 @@ class Seq2SeqLMBatch:
             stopping_criterias.append(
                 StoppingCriteria.from_pb(r.stopping_parameters, tokenizer)
             )
+            decoder_logprobs.append(None)
 
         # Tokenize batch
         pad_to_multiple_of = 8 if "gpu" in str(device) else None
@@ -95,6 +98,7 @@ class Seq2SeqLMBatch:
             past_key_values=None,
             input_lengths=input_lengths,
             decoder_input_lengths=decoder_input_lengths,
+            decoder_logprobs=decoder_logprobs,
             next_token_choosers=next_token_choosers,
             stopping_criterias=stopping_criterias,
             size=len(pb.requests),
@@ -117,6 +121,7 @@ class Seq2SeqLMBatch:
         requests = []
         input_lengths = []
         decoder_input_lengths = []
+        decoder_logprobs = []
         next_token_choosers = []
         stopping_criterias = []
 
@@ -137,6 +142,7 @@ class Seq2SeqLMBatch:
             requests.extend(batch.requests)
             input_lengths.extend(batch.input_lengths)
             decoder_input_lengths.extend(batch.decoder_input_lengths)
+            decoder_logprobs.extend(batch.decoder_logprobs)
             next_token_choosers.extend(batch.next_token_choosers)
             stopping_criterias.extend(batch.stopping_criterias)
 
@@ -286,6 +292,7 @@ class Seq2SeqLMBatch:
             past_key_values=past_key_values,
             input_lengths=input_lengths,
             decoder_input_lengths=decoder_input_lengths,
+            decoder_logprobs=decoder_logprobs,
             next_token_choosers=next_token_choosers,
             stopping_criterias=stopping_criterias,
             size=total_batch_size,
@@ -385,6 +392,7 @@ class Seq2SeqLM(Model):
         next_batch_input_lengths = []
         next_batch_decoder_input_ids = []
         next_batch_decoder_input_lengths = []
+        next_batch_decoder_logprobs = []
 
         # Metadata
         next_batch_size = 0
@@ -399,6 +407,7 @@ class Seq2SeqLM(Model):
             batch.requests,
             batch.input_lengths,
             batch.decoder_input_lengths,
+            batch.decoder_logprobs,
             logits,
             batch.next_token_choosers,
             batch.stopping_criterias,
@@ -411,38 +420,58 @@ class Seq2SeqLM(Model):
             request,
             input_length,
             decoder_input_length,
+            decoder_logprobs,
             logits,
             next_token_chooser,
             stopping_criteria,
             input_tokens,
-            decoder_tokens,
+            decoder_input_ids,
         ) in enumerate(iterator):
-            all_tokens = torch.cat([input_tokens, decoder_tokens])
             # Select next token
-            next_token = next_token_chooser(all_tokens, logits.unsqueeze(0)[:, -1])
+            next_token, logprobs = next_token_chooser(decoder_input_ids, logits)
 
             # Append next token to decoder tokens
-            decoder_tokens = torch.cat([decoder_tokens, next_token.squeeze(1)])
+            decoder_input_ids = torch.cat([decoder_input_ids, next_token])
+            new_decoder_input_length = decoder_input_length + 1
+
+            next_token_logprob = logprobs[-1, next_token]
+            if decoder_logprobs is None:
+                decoder_logprobs = next_token_logprob
+            else:
+                decoder_logprobs = torch.cat([decoder_logprobs, next_token_logprob])
 
             # Evaluate stopping criteria
-            stop, reason = stopping_criteria(decoder_tokens)
+            stop, reason = stopping_criteria(decoder_input_ids)
             if stop:
-                # Decode tokens
-                output = self.tokenizer.decode(decoder_tokens, skip_special_tokens=True)
+                # Slice with decoder_input_length to remove padding
+                # Decode all tokens
+                token_ids = decoder_input_ids[-new_decoder_input_length:]
+                output_text = self.tokenizer.decode(token_ids, skip_special_tokens=True)
+                tokens = self.tokenizer.batch_decode(token_ids)
+                # Add NaN for the bos token
+                logprobs = [float("nan")] + decoder_logprobs[
+                    -new_decoder_input_length:
+                ].tolist()
                 # Add to the list of finished generations with the original request
                 generated_texts.append(
                     GeneratedText(
-                        request, output, stopping_criteria.current_tokens, reason
+                        request=request,
+                        output_text=output_text,
+                        generated_tokens=stopping_criteria.current_tokens,
+                        tokens=tokens,
+                        token_ids=token_ids.tolist(),
+                        logprobs=logprobs,
+                        reason=reason,
                     )
                 )
             # add to the next batch
             else:
                 next_batch_keep_indices.append(i)
-                next_batch_decoder_input_ids.append(decoder_tokens.unsqueeze(0))
+                next_batch_decoder_input_ids.append(decoder_input_ids.unsqueeze(0))
                 next_batch_size += 1
-                new_decoder_input_length = decoder_input_length + 1
                 next_batch_input_lengths.append(input_length)
                 next_batch_decoder_input_lengths.append(new_decoder_input_length)
+                next_batch_decoder_logprobs.append(decoder_logprobs)
                 next_batch_max_input_length = max(
                     next_batch_max_input_length, input_length
                 )
@@ -515,6 +544,7 @@ class Seq2SeqLM(Model):
             past_key_values=next_batch_past_key_values,
             input_lengths=next_batch_input_lengths,
             decoder_input_lengths=next_batch_decoder_input_lengths,
+            decoder_logprobs=next_batch_decoder_logprobs,
             next_token_choosers=next_batch_next_token_choosers,
             stopping_criterias=next_batch_stopping_criterias,
             size=next_batch_size,
diff --git a/server/text_generation/models/types.py b/server/text_generation/models/types.py
index 91ec75d0..e76cf697 100644
--- a/server/text_generation/models/types.py
+++ b/server/text_generation/models/types.py
@@ -30,14 +30,20 @@ class Batch(ABC):
 @dataclass
 class GeneratedText:
     request: generate_pb2.Request
-    output: str
-    tokens: int
+    output_text: str
+    generated_tokens: int
+    tokens: List[str]
+    token_ids: List[int]
+    logprobs: List[float]
     reason: str
 
     def to_pb(self) -> generate_pb2.GeneratedText:
         return generate_pb2.GeneratedText(
             request=self.request,
-            output=self.output,
+            output_text=self.output_text,
+            generated_tokens=self.generated_tokens,
             tokens=self.tokens,
+            token_ids=self.token_ids,
+            logprobs=self.logprobs,
             finish_reason=self.reason,
         )
diff --git a/server/text_generation/utils.py b/server/text_generation/utils.py
index 661df05e..9dd91151 100644
--- a/server/text_generation/utils.py
+++ b/server/text_generation/utils.py
@@ -55,12 +55,16 @@ class NextTokenChooser:
         self.choice = Sampling() if sampling else Greedy()
 
     def __call__(self, input_ids, scores):
+        # Warp logits
         scores = self.warpers(input_ids, scores)
+        # Compute logprobs
+        logprobs = torch.log_softmax(scores, -1)
+        # Choose tokens
         next_ids = self.choice(scores)
-        return next_ids.unsqueeze(-1)
+        return next_ids, logprobs
 
     @classmethod
-    def from_pb(cls, pb: generate_pb2.LogitsWarperParameters) -> "NextTokenChooser":
+    def from_pb(cls, pb: generate_pb2.NextTokenChooserParameters) -> "NextTokenChooser":
         return NextTokenChooser(
             temperature=pb.temperature,
             top_k=pb.top_k,