diff --git a/src/cli-main.ts b/src/cli-main.ts
index 8891e83..a0dcd8a 100644
--- a/src/cli-main.ts
+++ b/src/cli-main.ts
@@ -67,6 +67,7 @@ export async function main(options: Options = {}) {
       '--silent',
       'Supress non-error logs (excluding "onSuccess" process output)'
     )
+    .option('--pure <express>', 'Mark specific expressions as pure')
     .action(async (files: string[], flags) => {
       const { build } = await import('.')
       Object.assign(options, {
diff --git a/src/index.ts b/src/index.ts
index 0b6a43c..5a0ca88 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -101,6 +101,10 @@ export type Options = {
    * Skip node_modules bundling
    */
   skipNodeModulesBundle?: boolean
+  /**
+   * @see https://esbuild.github.io/api/#pure
+   */
+  pure?: string | string[]
 }
 
 export type NormalizedOptions = MarkRequired<
@@ -204,6 +208,7 @@ export async function runEsbuild(
       minifySyntax: options.minifySyntax,
       keepNames: options.keepNames,
       incremental: !!options.watch,
+      pure: typeof options.pure === 'string' ? [options.pure] : options.pure,
     })
   } catch (error) {
     log(format, 'error', 'Build failed')