diff --git a/src/server/startup.gleam b/src/server/startup.gleam
index 5d0d90b..a8ace40 100644
--- a/src/server/startup.gleam
+++ b/src/server/startup.gleam
@@ -242,6 +242,8 @@ pub fn get_members(
   database: pog.Connection,
   id: uuid.Uuid,
 ) -> Result(List(user.User), StartupError) {
+  use <- ensure_exists(database, id)
+
   use returned <- result.map(
     sql.get_members(database, id)
     |> result.map_error(DatabaseError),
@@ -263,24 +265,41 @@ pub fn get_segments(
   database: pog.Connection,
   id: uuid.Uuid,
 ) -> Result(List(segment.Segment), StartupError) {
-  use returned <- result.try(
+  use <- ensure_exists(database, id)
+
+  use returned <- result.map(
     sql.get_segments(database, id)
     |> result.map_error(DatabaseError),
   )
 
+  use row <- list.map(returned.rows)
+  segment.Segment(id: row.id, name: row.name, description: row.description)
+}
+
+/// Returns `Error(NotFound)` if a startup is not registered in the Database
+///
+/// ## Examples
+///
+/// ```gleam
+/// use <- ensure_exists(database, id)
+///
+/// use returned <- result.map(
+///   sql.get_members(database, id)
+///   |> result.map_error(DatabaseError),
+/// )
+/// ```
+pub fn ensure_exists(
+  database: pog.Connection,
+  id: uuid.Uuid,
+  fun: fn() -> Result(a, StartupError),
+) -> Result(a, StartupError) {
+  use returned <- result.try(
+    sql.ensure_exists(database, id)
+    |> result.map_error(DatabaseError),
+  )
+
   case returned.rows {
     [] -> Error(NotFound)
-    rows -> {
-      let segments =
-        list.map(rows, fn(row) {
-          segment.Segment(
-            id: row.id,
-            name: row.name,
-            description: row.description,
-          )
-        })
-
-      Ok(segments)
-    }
+    _found -> fun()
   }
 }
diff --git a/src/server/startup/sql.gleam b/src/server/startup/sql.gleam
index 5a35239..b87eae3 100644
--- a/src/server/startup/sql.gleam
+++ b/src/server/startup/sql.gleam
@@ -52,6 +52,44 @@ RETURNING
   |> pog.execute(db)
 }
 
+/// A row you get from running the `ensure_exists` query
+/// defined in `./src/server/startup/sql/ensure_exists.sql`.
+///
+/// > 🐿️ This type definition was generated automatically using v4.7.0 of the
+/// > [squirrel package](https://github.com/giacomocavalieri/squirrel).
+///
+pub type EnsureExistsRow {
+  EnsureExistsRow(found: Int)
+}
+
+/// return a single column if the given startup exists
+///
+/// > 🐿️ This function was generated automatically using v4.7.0 of
+/// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
+///
+pub fn ensure_exists(
+  db: pog.Connection,
+  arg_1: Uuid,
+) -> Result(pog.Returned(EnsureExistsRow), pog.QueryError) {
+  let decoder = {
+    use found <- decode.field(0, decode.int)
+    decode.success(EnsureExistsRow(found:))
+  }
+
+  "-- return a single column if the given startup exists
+SELECT
+    1 AS found
+FROM
+    startup AS s
+WHERE
+    s.id = $1::uuid;
+"
+  |> pog.query
+  |> pog.parameter(pog.text(uuid.to_string(arg_1)))
+  |> pog.returning(decoder)
+  |> pog.execute(db)
+}
+
 /// A row you get from running the `get` query
 /// defined in `./src/server/startup/sql/get.sql`.
 ///
diff --git a/src/server/startup/sql/ensure_exists.sql b/src/server/startup/sql/ensure_exists.sql
new file mode 100644
index 0000000..327d4a1
--- /dev/null
+++ b/src/server/startup/sql/ensure_exists.sql
@@ -0,0 +1,7 @@
+-- return a single column if the given startup exists
+SELECT
+    1 AS found
+FROM
+    startup AS s
+WHERE
+    s.id = $1::uuid;
diff --git a/test/server/startup_test.gleam b/test/server/startup_test.gleam
index 3823cef..dfb547a 100644
--- a/test/server/startup_test.gleam
+++ b/test/server/startup_test.gleam
@@ -119,9 +119,15 @@ pub fn assign_startup_members_test() -> Nil {
 pub fn get_startup_members_test() -> Nil {
   use context <- server_test.with_context()
 
-  let cnpj = wisp.random_string(14)
   let assert Ok(startup) =
-    startup.register(context.database, "", cnpj, "", "", "")
+    startup.register(
+      context.database,
+      name: "startup",
+      cnpj: "00000000000000",
+      description: "some description",
+      city: "Recife",
+      state: "PE",
+    )
 
   let members = {
     use acc, i <- int.range(from: 1, to: 8, with: [])
@@ -140,8 +146,8 @@ pub fn get_startup_members_test() -> Nil {
     )
 
   let want = set.from_list(members)
-  let assert Ok(got) =
-    result.map(startup.get_members(context.database, startup.id), set.from_list)
+  let assert Ok(got) = startup.get_members(context.database, startup.id)
+  let got = set.from_list(got)
 
   assert set.difference(want, got) == set.from_list([])
 }