diff --git a/src/api/apiUtils.js b/src/api/apiUtils.js
new file mode 100644
index 0000000..a97e14f
--- /dev/null
+++ b/src/api/apiUtils.js
@@ -0,0 +1,17 @@
+export async function handleResponse(response) {
+  if (response.ok) return response.json();
+  if (response.status === 400) {
+    // So, a server-side validation error occurred.
+    // Server side validation returns a string error message, so parse as text instead of json.
+    const error = await response.text();
+    throw new Error(error);
+  }
+  throw new Error("Network response was not ok.");
+}
+
+// In a real app, would likely call an error logging service.
+export function handleError(error) {
+  // eslint-disable-next-line no-console
+  console.error("API call failed. " + error);
+  throw error;
+}
diff --git a/src/api/authorApi.js b/src/api/authorApi.js
new file mode 100644
index 0000000..6c8ba73
--- /dev/null
+++ b/src/api/authorApi.js
@@ -0,0 +1,22 @@
+import { handleResponse, handleError } from "./apiUtils";
+const baseUrl = process.env.REACT_APP_API_URL + "/authors/";
+
+export function getAuthors() {
+  return fetch(baseUrl).then(handleResponse).catch(handleError);
+}
+
+export function saveAuthor(author) {
+  return fetch(baseUrl + (author.id || ""), {
+    method: author.id ? "PUT" : "POST", // POST for create, PUT to update when id already exists.
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify(author),
+  })
+    .then(handleResponse)
+    .catch(handleError);
+}
+
+export function deleteAuthor(authorId) {
+  return fetch(baseUrl + authorId, { method: "DELETE" })
+    .then(handleResponse)
+    .catch(handleError);
+}
diff --git a/src/api/courseApi.js b/src/api/courseApi.js
new file mode 100644
index 0000000..eabadcc
--- /dev/null
+++ b/src/api/courseApi.js
@@ -0,0 +1,39 @@
+import { handleResponse, handleError } from "./apiUtils";
+
+const baseUrl = process.env.REACT_APP_API_URL + "/courses/";
+
+export function getCourses() {
+  return fetch(baseUrl).then(handleResponse).catch(handleError);
+}
+
+export function getCourseBySlug(slug) {
+  return fetch(baseUrl + "?slug=" + slug)
+    .then((response) => {
+      if (!response.ok) throw new Error("Network response was not ok.");
+      return response.json().then((courses) => {
+        if (courses.length !== 1) throw new Error("Course not found: " + slug);
+        return courses[0]; // should only find one course for a given slug, so return it.
+      });
+    })
+    .catch(handleError);
+}
+
+export function saveCourse(course) {
+  return fetch(baseUrl + (course.id || ""), {
+    method: course.id ? "PUT" : "POST", // POST for create, PUT to update when id already exists.
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify({
+      ...course,
+      // Parse authorId to a number (in case it was sent as a string).
+      authorId: parseInt(course.authorId, 10),
+    }),
+  })
+    .then(handleResponse)
+    .catch(handleError);
+}
+
+export function deleteCourse(courseId) {
+  return fetch(baseUrl + courseId, { method: "DELETE" })
+    .then(handleResponse)
+    .catch(handleError);
+}
diff --git a/src/api/userApi.js b/src/api/userApi.js
new file mode 100644
index 0000000..cd25ac6
--- /dev/null
+++ b/src/api/userApi.js
@@ -0,0 +1,39 @@
+import { handleResponse, handleError } from "./apiUtils";
+
+const baseUrl = process.env.REACT_APP_API_URL + "/users/";
+
+export function getUsers() {
+  return fetch(baseUrl).then(handleResponse).catch(handleError);
+}
+
+export function getUserBySlug(slug) {
+  return fetch(baseUrl + "?slug=" + slug)
+    .then((response) => {
+      if (!response.ok) throw new Error("Network response was not ok.");
+      return response.json().then((users) => {
+        if (users.length !== 1) throw new Error("User not found: " + slug);
+        return users[0]; // should only find one user for a given slug, so return it.
+      });
+    })
+    .catch(handleError);
+}
+
+export function saveUser(user) {
+  return fetch(baseUrl + (user.id || ""), {
+    method: user.id ? "PUT" : "POST", // POST for create, PUT to update when id already exists.
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify({
+      ...user,
+      // Parse authorId to a number (in case it was sent as a string).
+      id: parseInt(user.id, 10),
+    }),
+  })
+    .then(handleResponse)
+    .catch(handleError);
+}
+
+export function deleteUser(userId) {
+  return fetch(baseUrl + userId, { method: "DELETE" })
+    .then(handleResponse)
+    .catch(handleError);
+}