diff --git a/src/cli/generateSpec.ts b/src/cli/generateSpec.ts
index 3701b5b..0f2a08a 100644
--- a/src/cli/generateSpec.ts
+++ b/src/cli/generateSpec.ts
@@ -1,6 +1,7 @@
 import { writeFile } from 'node:fs/promises'
 import path from 'node:path'
 
+import type { CLICommand } from 'payload'
 import { strictObject, z } from 'payload'
 import { defineCLICommand } from 'payload/cli'
 
@@ -10,7 +11,7 @@ import type { ResolvedOptions } from '@/shared/types/index.js'
 
 const optionalString = (description: string) => z.optional(z.string()).check(z.describe(description))
 
-export const generateSpecCommand = defineCLICommand({
+export const generateSpecCommand: CLICommand = defineCLICommand({
   description: 'Write the OpenAPI document to a file.',
   input: strictObject({
     lang: optionalString(
diff --git a/src/index.ts b/src/index.ts
index f95f9ca..7984425 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,6 @@
 import { fileURLToPath } from 'node:url'
 
+import type { Plugin } from 'payload'
 import { definePlugin } from 'payload'
 
 import { interactiveAuthHandler } from '@/server/endpoints/interactiveAuth.js'
@@ -19,7 +20,7 @@ const resolveCommandPath = (): string => {
   return `${fileURLToPath(new URL(`./cli/generateSpec${ext}`, selfUrl))}#generateSpecCommand`
 }
 
-export const openapi = definePlugin<OpenApiPluginOptions>({
+export const openapi: (options: OpenApiPluginOptions) => Plugin = definePlugin<OpenApiPluginOptions>({
   slug: PLUGIN_NAME,
   plugin: ({ config, options, plugins }) => {
     const resolved = resolveOptions(options)
diff --git a/src/server/spec/fields.ts b/src/server/spec/fields.ts
index 218eef9..553ca35 100644
--- a/src/server/spec/fields.ts
+++ b/src/server/spec/fields.ts
@@ -2,7 +2,7 @@ import type { Field, NamedTab } from 'payload'
 
 export const isHiddenField = (field: Field): boolean => 'hidden' in field && field.hidden === true
 
-export const AUTH_FIELDS = new Set([
+export const AUTH_FIELDS: Set<string> = new Set([
   'salt',
   'hash',
   'password',
diff --git a/src/server/ui/createUiPlugin.ts b/src/server/ui/createUiPlugin.ts
index 3aec3e2..8c1a29f 100644
--- a/src/server/ui/createUiPlugin.ts
+++ b/src/server/ui/createUiPlugin.ts
@@ -1,3 +1,4 @@
+import type { Plugin } from 'payload'
 import { definePlugin, Forbidden } from 'payload'
 
 import { assertNoRemovedKeys } from '@/server/options/resolveOptions.js'
@@ -19,7 +20,7 @@ export interface UiPluginSpec {
   render: (args: UiRenderArgs) => string
 }
 
-export const createUiPlugin = (spec: UiPluginSpec) =>
+export const createUiPlugin = (spec: UiPluginSpec): ((options?: UiPluginOptions) => Plugin) =>
   definePlugin<UiPluginOptions | undefined>({
     slug: spec.slug,
     plugin: ({ config, options = {} }) => {
diff --git a/src/server/ui/scalar.ts b/src/server/ui/scalar.ts
index 52ed1a9..31cd279 100644
--- a/src/server/ui/scalar.ts
+++ b/src/server/ui/scalar.ts
@@ -1,11 +1,14 @@
+import type { Plugin } from 'payload'
+
 import { SCALAR_PLUGIN_NAME } from '@/shared/constants.js'
+import type { UiPluginOptions } from '@/shared/types/index.js'
 
 import { createUiPlugin } from './createUiPlugin.js'
 import { escapeHtml, htmlPage, integrityAttrs, jsonForScript, specUrlExpr } from './html.js'
 
 const SCRIPT_INTEGRITY = 'sha384-omTRdD9MbjA1vm12DqRUVvqJlr3VzSixvAdF1Jruu9AJOiJKyTKraIB6DyX+m10M'
 
-export const scalar = createUiPlugin({
+export const scalar: (options?: UiPluginOptions) => Plugin = createUiPlugin({
   slug: SCALAR_PLUGIN_NAME,
   defaultDocsUrl: '/docs',
   defaultCdnBase: 'https://cdn.jsdelivr.net/npm/@scalar/api-reference@1.72.4/dist/browser/standalone.js',
diff --git a/src/server/ui/swagger.ts b/src/server/ui/swagger.ts
index 2189d9d..ae41ec2 100644
--- a/src/server/ui/swagger.ts
+++ b/src/server/ui/swagger.ts
@@ -1,4 +1,7 @@
+import type { Plugin } from 'payload'
+
 import { SWAGGER_UI_PLUGIN_NAME } from '@/shared/constants.js'
+import type { UiPluginOptions } from '@/shared/types/index.js'
 
 import { createUiPlugin } from './createUiPlugin.js'
 import { escapeHtml, htmlPage, integrityAttrs, jsonForScript, specUrlExpr } from './html.js'
@@ -6,7 +9,7 @@ import { escapeHtml, htmlPage, integrityAttrs, jsonForScript, specUrlExpr } from
 const STYLE_INTEGRITY = 'sha384-Ov4/wv3j2bmct8cDc5X4ngJZohVPzEmc6uDPH8WeljUxO5vtoykvMEfbu9Vh6RaW'
 const SCRIPT_INTEGRITY = 'sha384-ZPehFMQommnnuaZ4rpxgkgTT2DKFVp4hZC/7pLit+9Lek9T1YGSo23eHFbvNkXkw'
 
-export const swaggerUi = createUiPlugin({
+export const swaggerUi: (options?: UiPluginOptions) => Plugin = createUiPlugin({
   slug: SWAGGER_UI_PLUGIN_NAME,
   defaultDocsUrl: '/docs',
   defaultCdnBase: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.33.1',
diff --git a/src/shared/constants.ts b/src/shared/constants.ts
index 021aeb2..188081d 100644
--- a/src/shared/constants.ts
+++ b/src/shared/constants.ts
@@ -1,3 +1,3 @@
 export const PLUGIN_NAME = '@seshuk/payload-plugin-openapi'
-export const SCALAR_PLUGIN_NAME = `${PLUGIN_NAME}/scalar`
-export const SWAGGER_UI_PLUGIN_NAME = `${PLUGIN_NAME}/swagger-ui`
+export const SCALAR_PLUGIN_NAME: `${typeof PLUGIN_NAME}/scalar` = `${PLUGIN_NAME}/scalar`
+export const SWAGGER_UI_PLUGIN_NAME: `${typeof PLUGIN_NAME}/swagger-ui` = `${PLUGIN_NAME}/swagger-ui`
diff --git a/tsconfig.build.json b/tsconfig.build.json
index a89dd00..69d4592 100644
--- a/tsconfig.build.json
+++ b/tsconfig.build.json
@@ -4,7 +4,10 @@
     "jsx": "react-jsx",
     "rootDir": "./src",
     "outDir": "./dist",
-    "noEmit": false
+    "noEmit": false,
+    "declaration": true,
+    "isolatedDeclarations": true,
+    "allowJs": false
   },
   "include": ["./src/**/*.ts", "./src/**/*.tsx"],
   "exclude": ["./tests"]