diff --git a/src/bin/trainee-tracker.rs b/src/bin/trainee-tracker.rs
index acbe439..5239e0c 100644
--- a/src/bin/trainee-tracker.rs
+++ b/src/bin/trainee-tracker.rs
@@ -100,6 +100,10 @@ async fn main() {
             "/groups/slack.csv",
             get(trainee_tracker::frontend::list_slack_groups_csv),
         )
+        .route(
+            "/api/attendance",
+            get(trainee_tracker::endpoints::fetch_attendance),
+        )
         .layer(session_layer)
         .with_state(server_state);
 
diff --git a/src/endpoints.rs b/src/endpoints.rs
index 1d5ebdb..56f3f73 100644
--- a/src/endpoints.rs
+++ b/src/endpoints.rs
@@ -1,3 +1,5 @@
+use std::collections::BTreeMap;
+
 use ::octocrab::models::{teams::RequestedTeam, Author};
 use anyhow::Context;
 use axum::{
@@ -15,6 +17,7 @@ use crate::{
     newtypes::GithubLogin,
     octocrab::{all_pages, octocrab},
     prs::{fill_in_reviewers, get_prs, PrWithReviews},
+    register::{get_register, Attendance},
     sheets::sheets_client,
     Error, ServerState,
 };
@@ -207,3 +210,76 @@ pub async fn get_region(
             .map(|trainee| trainee.region.clone()),
     }))
 }
+
+type SprintAttendance = BTreeMap<String, Vec<Attendance>>;
+type ModuleAttendance = BTreeMap<String, SprintAttendance>;
+type BatchAttendance = BTreeMap<String, ModuleAttendance>;
+type CourseAttendance = BTreeMap<String, BatchAttendance>;
+
+#[derive(Serialize)]
+pub struct AttendanceResponse {
+    courses: CourseAttendance,
+}
+
+pub async fn fetch_attendance(
+    session: Session,
+    State(server_state): State<ServerState>,
+    OriginalUri(original_uri): OriginalUri,
+) -> Result<Json<AttendanceResponse>, Error> {
+    let all_courses = &server_state.config.courses;
+    let sheets_client = sheets_client(&session, server_state.clone(), original_uri.clone()).await?;
+
+    let mut courses: CourseAttendance = BTreeMap::new();
+    let mut register_futures = Vec::new();
+    for (course_name, course_info) in all_courses {
+        for batch_name in course_info.batches.keys() {
+            let course_schedule = server_state
+                .config
+                .get_course_schedule_with_register_sheet_id(course_name.clone(), batch_name)
+                .ok_or_else(|| Error::Fatal(anyhow::anyhow!("Course not found: {course_name}")))?;
+            let register_future = get_register(
+                sheets_client.clone(),
+                course_schedule.register_sheet_id.clone(),
+                course_schedule.course_schedule.start,
+                course_schedule.course_schedule.end,
+            );
+            register_futures.push(async move {
+                (
+                    course_name.clone(),
+                    batch_name.clone(),
+                    register_future.await,
+                )
+            });
+        }
+    }
+    let register_info = join_all(register_futures).await;
+
+    for (course_name, batch_name, register_result) in register_info {
+        let register = register_result?;
+        let modules = register
+            .modules
+            .into_iter()
+            .map(|(module_name, sprint_info)| {
+                (
+                    module_name,
+                    sprint_info
+                        .attendance
+                        .into_iter()
+                        .enumerate()
+                        .map(|(sprint_number, sprint_info)| {
+                            (
+                                format!("Sprint-{}", sprint_number + 1),
+                                sprint_info.into_values().collect(),
+                            )
+                        })
+                        .collect(),
+                )
+            })
+            .collect();
+        courses
+            .entry(course_name)
+            .or_default()
+            .insert(batch_name, modules);
+    }
+    Ok(Json(AttendanceResponse { courses }))
+}
diff --git a/src/register.rs b/src/register.rs
index e904295..97918a3 100644
--- a/src/register.rs
+++ b/src/register.rs
@@ -4,6 +4,7 @@ use anyhow::Context;
 use chrono::{DateTime, NaiveDate, Utc};
 use email_address::EmailAddress;
 use indexmap::IndexMap;
+use serde::Serialize;
 use sheets::types::{CellData, GridData};
 use tracing::warn;
 
@@ -24,7 +25,7 @@ pub struct ModuleAttendance {
     pub attendance: Vec<IndexMap<EmailAddress, Attendance>>,
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize)]
 pub struct Attendance {
     pub name: String,
     pub email: EmailAddress,