diff --git a/messages/avoid-write-client-in-browser.md b/messages/avoid-write-client-in-browser.md
index c20834ce..d88dbc9f 100644
--- a/messages/avoid-write-client-in-browser.md
+++ b/messages/avoid-write-client-in-browser.md
@@ -9,7 +9,6 @@ import * as prismic from "@prismicio/client";
 
 const writeClient = prismic.createWriteClient("example-prismic-repo", {
 	writeToken: "xxx"
-	migrationAPIKey: "yyy"
 })
 ```
 
diff --git a/src/WriteClient.ts b/src/WriteClient.ts
index a2e75851..3f42feba 100644
--- a/src/WriteClient.ts
+++ b/src/WriteClient.ts
@@ -224,6 +224,18 @@ const ASSET_CREDITS_MAX_LENGTH = 500
  */
 const ASSET_ALT_MAX_LENGTH = 500
 
+/**
+ * Prismic migration API demo keys.
+ */
+const MIGRATION_API_DEMO_KEYS = [
+	"cSaZlfkQlF9C6CEAM2Del6MNX9WonlV86HPbeEJL",
+	"pZCexCajUQ4jriYwIGSxA1drZrFxDyFf1S0D1K0P",
+	"Yc0mfrkGDw8gaaGKTrzwC3QUZDajv6k73DA99vWN",
+	"ySzSEbVMAb5S1oSCQfbVG4mbh9Cb8wlF7BCvKI0L",
+	"g2DA3EKWvx8uxVYcNFrmT5nJpon1Vi9V4XcOibJD",
+	"CCNIlI0Vz41J66oFwsHUXaZa6NYFIY6z7aDF62Bc",
+]
+
 /**
  * Checks if a string is an asset tag ID.
  *
@@ -297,12 +309,45 @@ export const validateAssetMetadata = ({
  * Configuration for clients that determine how content is queried.
  */
 export type WriteClientConfig = {
+	/**
+	 * A Prismic write token that allows writing content to the repository.
+	 */
 	writeToken: string
 
-	migrationAPIKey: string
+	/**
+	 * An explicit Prismic migration API key that allows working with the
+	 * migration API. If none is provided, the client will pick a random one to
+	 * authenticate your requests.
+	 *
+	 * @remarks
+	 * Those keys are the same for all Prismic users. They are only useful while
+	 * the migration API is in beta to reduce load. It should be one of:
+	 *
+	 * - `cSaZlfkQlF9C6CEAM2Del6MNX9WonlV86HPbeEJL`
+	 * - `pZCexCajUQ4jriYwIGSxA1drZrFxDyFf1S0D1K0P`
+	 * - `Yc0mfrkGDw8gaaGKTrzwC3QUZDajv6k73DA99vWN`
+	 * - `ySzSEbVMAb5S1oSCQfbVG4mbh9Cb8wlF7BCvKI0L`
+	 * - `g2DA3EKWvx8uxVYcNFrmT5nJpon1Vi9V4XcOibJD`
+	 * - `CCNIlI0Vz41J66oFwsHUXaZa6NYFIY6z7aDF62Bc`
+	 */
+	migrationAPIKey?: string
 
+	/**
+	 * The Prismic asset API endpoint.
+	 *
+	 * @defaultValue `"https://asset-api.prismic.io/"`
+	 *
+	 * @see Prismic asset API technical references: {@link https://prismic.io/docs/asset-api-technical-reference}
+	 */
 	assetAPIEndpoint?: string
 
+	/**
+	 * The Prismic migration API endpoint.
+	 *
+	 * @defaultValue `"https://migration.prismic.io/"`
+	 *
+	 * @see Prismic migration API technical references: {@link https://prismic.io/docs/migration-api-technical-reference}
+	 */
 	migrationAPIEndpoint?: string
 } & ClientConfig
 
@@ -349,7 +394,11 @@ export class WriteClient<
 		}
 
 		this.writeToken = options.writeToken
-		this.migrationAPIKey = options.migrationAPIKey
+		this.migrationAPIKey =
+			options.migrationAPIKey ||
+			MIGRATION_API_DEMO_KEYS[
+				Math.floor(Math.random() * MIGRATION_API_DEMO_KEYS.length)
+			]
 
 		if (options.assetAPIEndpoint) {
 			this.assetAPIEndpoint = `${options.assetAPIEndpoint}/`
diff --git a/test/__testutils__/createWriteClient.ts b/test/__testutils__/createWriteClient.ts
index 962d8ceb..32ebde3b 100644
--- a/test/__testutils__/createWriteClient.ts
+++ b/test/__testutils__/createWriteClient.ts
@@ -21,7 +21,6 @@ export const createTestWriteClient = (
 	return prismic.createWriteClient(repositoryName, {
 		fetch,
 		writeToken: "xxx",
-		migrationAPIKey: "yyy",
 		// We create unique endpoints so we can run tests concurrently
 		assetAPIEndpoint: `https://${repositoryName}.asset-api.prismic.io`,
 		migrationAPIEndpoint: `https://${repositoryName}.migration.prismic.io`,
diff --git a/test/writeClient.test.ts b/test/writeClient.test.ts
index b2ba0466..55381e7c 100644
--- a/test/writeClient.test.ts
+++ b/test/writeClient.test.ts
@@ -6,7 +6,6 @@ it("`createWriteClient` creates a write client", () => {
 	const client = prismic.createWriteClient("qwerty", {
 		fetch: vi.fn(),
 		writeToken: "xxx",
-		migrationAPIKey: "yyy",
 	})
 
 	expect(client).toBeInstanceOf(prismic.WriteClient)
@@ -23,7 +22,6 @@ it("constructor warns if running in a browser-like environment", () => {
 	prismic.createWriteClient("qwerty", {
 		fetch: vi.fn(),
 		writeToken: "xxx",
-		migrationAPIKey: "yyy",
 	})
 	expect(consoleWarnSpy).toHaveBeenCalledWith(
 		expect.stringMatching(/avoid-write-client-in-browser/i),
@@ -39,7 +37,6 @@ it("uses provided asset API endpoint and adds `/` suffix", () => {
 		fetch: vi.fn(),
 		assetAPIEndpoint: "https://example.com",
 		writeToken: "xxx",
-		migrationAPIKey: "yyy",
 	})
 
 	expect(client.assetAPIEndpoint).toBe("https://example.com/")
@@ -50,8 +47,17 @@ it("uses provided migration API endpoint and adds `/` suffix", () => {
 		fetch: vi.fn(),
 		migrationAPIEndpoint: "https://example.com",
 		writeToken: "xxx",
-		migrationAPIKey: "yyy",
 	})
 
 	expect(client.migrationAPIEndpoint).toBe("https://example.com/")
 })
+
+it("uses provided migration API key", () => {
+	const client = prismic.createWriteClient("qwerty", {
+		fetch: vi.fn(),
+		writeToken: "xxx",
+		migrationAPIKey: "yyy",
+	})
+
+	expect(client.migrationAPIKey).toBe("yyy")
+})