diff --git a/astroplant-api/src/bin/astroplant-api.rs b/astroplant-api/src/bin/astroplant-api.rs
index acf5ac7..56d9aee 100644
--- a/astroplant-api/src/bin/astroplant-api.rs
+++ b/astroplant-api/src/bin/astroplant-api.rs
@@ -65,6 +65,7 @@ async fn main() -> anyhow::Result<()> {
         .route("/kits/:kit_serial", patch(kit::patch_kit))
         .route("/kits/:kit_serial", delete(kit::delete_kit))
         .route("/kits/:kit_serial/members", get(kit::get_members))
+        .route("/kits/:kit_serial/members", post(kit::add_member))
         .route(
             "/kits/:kit_serial/member-suggestions",
             get(kit::get_member_suggestions),
diff --git a/astroplant-api/src/controllers/kit/mod.rs b/astroplant-api/src/controllers/kit/mod.rs
index 2468d50..a5f3756 100644
--- a/astroplant-api/src/controllers/kit/mod.rs
+++ b/astroplant-api/src/controllers/kit/mod.rs
@@ -1,5 +1,6 @@
 use axum::extract::Path;
 use axum::Extension;
+use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 
 use crate::authorization::KitAction;
@@ -291,6 +292,90 @@ pub async fn get_members(
     Ok(ResponseBuilder::ok().body(v))
 }
 
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AddMember {
+    username: String,
+    access_configure: bool,
+    access_super: bool,
+}
+
+/// Handles the `POST /kits/{kitSerial}/members` route.
+pub async fn add_member(
+    Extension(pg): Extension<PgPool>,
+    Path(kit_serial): Path<String>,
+    user_id: Option<models::UserId>,
+    crate::extract::Json(member): crate::extract::Json<AddMember>,
+) -> Result<Response, Problem> {
+    let action = if member.access_super {
+        crate::authorization::KitAction::EditSuperMembers
+    } else {
+        crate::authorization::KitAction::EditMembers
+    };
+    let (_, _, kit) =
+        helpers::fut_kit_permission_or_forbidden(pg.clone(), user_id, kit_serial, action).await?;
+
+    let conn = pg.get().await?;
+
+    let kit_id = kit.id;
+    let membership = conn
+        .interact_flatten_err(move |conn| {
+            use diesel::prelude::*;
+            use schema::kit_memberships;
+            use schema::users;
+
+            conn.build_transaction().serializable().run(move |conn| {
+                let user: User = users::table
+                    .filter(users::username.eq(&member.username))
+                    .first(conn)?;
+
+                let existing_membership: Option<KitMembership> = kit_memberships::table
+                    .filter(kit_memberships::kit_id.eq(kit_id))
+                    .filter(kit_memberships::user_id.eq(user.id))
+                    .get_result(conn)
+                    .optional()?;
+
+                if let Some(existing_membership) = existing_membership {
+                    // This membership already exists, do nothing
+                    return Ok::<_, Problem>(
+                        views::KitMembership::from(existing_membership)
+                            .with_user(views::User::from(user))
+                            .with_kit(views::Kit::from(kit)),
+                    );
+                }
+
+                #[derive(Insertable)]
+                #[diesel(table_name = kit_memberships)]
+                struct NewKitMembership {
+                    user_id: i32,
+                    kit_id: i32,
+                    access_super: bool,
+                    access_configure: bool,
+                    datetime_linked: DateTime<Utc>,
+                }
+
+                let membership = NewKitMembership {
+                    user_id: user.id,
+                    kit_id,
+                    access_super: member.access_super,
+                    access_configure: member.access_configure,
+                    datetime_linked: Utc::now(),
+                };
+                let membership: KitMembership = membership
+                    .insert_into(kit_memberships::table)
+                    .get_result(conn)?;
+
+                Ok::<_, Problem>(
+                    views::KitMembership::from(membership)
+                        .with_user(views::User::from(user))
+                        .with_kit(views::Kit::from(kit)),
+                )
+            })
+        })
+        .await?;
+
+    Ok(ResponseBuilder::ok().body(membership))
+}
 
 #[derive(Deserialize)]
 pub struct MemberSuggestions {
diff --git a/openapi.yaml b/openapi.yaml
index e42ab5b..3498c28 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -258,6 +258,42 @@ paths:
           description: The serial of the kit to get the members of.
           schema:
             type: string
+      responses:
+        '200':
+          description: The kit's members.
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/KitMembership"
+        '401':
+          $ref: "#/components/responses/ErrorUnauthorized"
+        '429':
+          $ref: "#/components/responses/ErrorRateLimit"
+        '500':
+          $ref: "#/components/responses/ErrorInternalServer"
+    post:
+      summary: Add a membership to a kit.
+      operationId: addKitMember
+      security:
+        - bearerAuth: []
+      tags:
+        - kits
+      parameters:
+        - name: kitSerial
+          in: path
+          required: true
+          description: The serial of the kit to add a membership to.
+          schema:
+            type: string
+      requestBody:
+        description: The membership to add.
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/NewKitMembership"
       responses:
         '200':
           description: The kit's members.
@@ -1406,6 +1442,19 @@ components:
         datetimeLinked:
           type: string
           format: "date-time"
+    NewKitMembership:
+      type: object
+      required:
+        - username
+        - accessConfigure
+        - accessSuper
+      properties:
+        username:
+          type: string
+        accessConfigure:
+          type: boolean
+        accessSuper:
+          type: boolean
     PatchKitMembership:
       type: object
       properties: