diff --git a/packages/workbox-build/src/generate-sw.ts b/packages/workbox-build/src/generate-sw.ts
index b03b4cd33..ba803fb4d 100644
--- a/packages/workbox-build/src/generate-sw.ts
+++ b/packages/workbox-build/src/generate-sw.ts
@@ -8,7 +8,7 @@
 
 import upath from 'upath';
 
-import {BuildResult, GetManifestOptions} from './types';
+import {BuildResult, GetManifestOptions, GenerateSWOptions} from './types';
 import {getFileManifestEntries} from './lib/get-file-manifest-entries';
 import {rebasePath} from './lib/rebase-path';
 import {validateGenerateSWOptions} from './lib/validate-options';
@@ -193,7 +193,9 @@ import {writeSWUsingDefaultTemplate} from './lib/write-sw-using-default-template
  *
  * @memberof workbox-build
  */
-export async function generateSW(config: unknown): Promise<BuildResult> {
+export async function generateSW(
+  config: GenerateSWOptions,
+): Promise<BuildResult> {
   const options = validateGenerateSWOptions(config);
   let entriesResult;
 
diff --git a/packages/workbox-build/src/get-manifest.ts b/packages/workbox-build/src/get-manifest.ts
index 2a66caa22..d9c1fce15 100644
--- a/packages/workbox-build/src/get-manifest.ts
+++ b/packages/workbox-build/src/get-manifest.ts
@@ -7,7 +7,7 @@
 */
 
 import {getFileManifestEntries} from './lib/get-file-manifest-entries';
-import {GetManifestResult} from './types';
+import {GetManifestOptions, GetManifestResult} from './types';
 import {validateGetManifestOptions} from './lib/validate-options';
 
 // eslint-disable-next-line jsdoc/newline-after-description
@@ -88,7 +88,9 @@ import {validateGetManifestOptions} from './lib/validate-options';
  *
  * @memberof workbox-build
  */
-export async function getManifest(config: unknown): Promise<GetManifestResult> {
+export async function getManifest(
+  config: GetManifestOptions,
+): Promise<GetManifestResult> {
   const options = validateGetManifestOptions(config);
 
   return await getFileManifestEntries(options);
diff --git a/packages/workbox-build/src/inject-manifest.ts b/packages/workbox-build/src/inject-manifest.ts
index 8c1a14a81..f31631591 100644
--- a/packages/workbox-build/src/inject-manifest.ts
+++ b/packages/workbox-build/src/inject-manifest.ts
@@ -12,7 +12,7 @@ import fse from 'fs-extra';
 import stringify from 'fast-json-stable-stringify';
 import upath from 'upath';
 
-import {BuildResult} from './types';
+import {BuildResult, InjectManifestOptions} from './types';
 import {errors} from './lib/errors';
 import {escapeRegExp} from './lib/escape-regexp';
 import {getFileManifestEntries} from './lib/get-file-manifest-entries';
@@ -117,7 +117,9 @@ import {validateInjectManifestOptions} from './lib/validate-options';
  *
  * @memberof workbox-build
  */
-export async function injectManifest(config: unknown): Promise<BuildResult> {
+export async function injectManifest(
+  config: InjectManifestOptions,
+): Promise<BuildResult> {
   const options = validateInjectManifestOptions(config);
 
   // Make sure we leave swSrc and swDest out of the precache manifest.
diff --git a/packages/workbox-cli/src/app.ts b/packages/workbox-cli/src/app.ts
index 4199f7c5b..614c92afc 100644
--- a/packages/workbox-cli/src/app.ts
+++ b/packages/workbox-cli/src/app.ts
@@ -34,7 +34,7 @@ interface BuildCommand {
  */
 async function runBuildCommand({command, config, watch}: BuildCommand) {
   const {count, filePaths, size, warnings} = await workboxBuild[command](
-    config,
+    config as any,
   );
 
   for (const warning of warnings) {