diff --git a/src/build/build-options.ts b/src/build/build-options.ts
index 8e959c8..06b5581 100644
--- a/src/build/build-options.ts
+++ b/src/build/build-options.ts
@@ -1,10 +1,12 @@
 import {IPolyfillFeature} from "../polyfill/i-polyfill-feature";
 import {PolyfillContext} from "../polyfill/polyfill-context";
+import {EcmaVersion} from "../util/type/ecma-version";
 
 export interface BuildOptions {
 	context: PolyfillContext;
 	features: IPolyfillFeature[];
 	featuresRequested: IPolyfillFeature[];
+	ecmaVersion: EcmaVersion;
 	paths: string[];
 	sourcemap?: boolean;
 	minify?: boolean;
diff --git a/src/build/build.ts b/src/build/build.ts
index 0ab2ecf..81604dd 100644
--- a/src/build/build.ts
+++ b/src/build/build.ts
@@ -1,6 +1,5 @@
 import {BuildOptions} from "./build-options";
 import {BuildResult} from "./build-result";
-import {generateBrowserslistFromUseragent, getAppropriateEcmaVersionForBrowserslist} from "@wessberg/browserslist-generator";
 import {brotliEncode, gzipEncode} from "./util/encoding";
 import {BROTLI_OPTIONS} from "./options/brotli-options";
 import {ZLIB_OPTIONS} from "./options/zlib-options";
@@ -49,7 +48,7 @@ function stringifyPolyfillFeature(feature: IPolyfillFeature): string {
 	return `${feature.name}${metaEntriesText.length === 0 ? "" : ` (${metaEntriesText})`}`;
 }
 
-export async function build({paths, features, featuresRequested, userAgent, context, sourcemap = false, minify = false}: BuildOptions): Promise<BuildResult> {
+export async function build({paths, features, featuresRequested, ecmaVersion, context, sourcemap = false, minify = false}: BuildOptions): Promise<BuildResult> {
 	const entryText = paths.map(path => `import "${path}";`).join("\n");
 
 	// Generate the intro text
@@ -69,13 +68,12 @@ export async function build({paths, features, featuresRequested, userAgent, cont
 
 	writeFileSync(tempInputFileLocation, entryText);
 
-	let ecmaVersion = userAgent == null ? "es3" : getAppropriateEcmaVersionForBrowserslist(generateBrowserslistFromUseragent(userAgent));
-
 	// esbuild only supports transforming down to es2015
 	const canUseOnlyEsbuild = ecmaVersion !== "es3" && ecmaVersion !== "es5";
 
 	try {
 		const result = await esbuild({
+			banner,
 			write: false,
 			format: "iife",
 			outfile: virtualOutputFileName,
@@ -127,10 +125,6 @@ export async function build({paths, features, featuresRequested, userAgent, cont
 			}));
 		}
 
-		if (!sourcemap) {
-			code = `${banner}${code}`;
-		}
-
 		// Apply encoding based on the given options
 		const raw = Buffer.from(code);
 		const brotli = await brotliEncode(raw, BROTLI_OPTIONS);
diff --git a/src/polyfill/i-polyfill-request.ts b/src/polyfill/i-polyfill-request.ts
index a533e42..f0c1a45 100644
--- a/src/polyfill/i-polyfill-request.ts
+++ b/src/polyfill/i-polyfill-request.ts
@@ -1,9 +1,11 @@
 import {IPolyfillFeatureInput} from "./i-polyfill-feature";
 import {ContentEncodingKind} from "../encoding/content-encoding-kind";
 import {PolyfillContext} from "./polyfill-context";
+import {EcmaVersion} from "../util/type/ecma-version";
 
 export interface IPolyfillRequest {
 	userAgent: string;
+	ecmaVersion: EcmaVersion;
 	encoding?: ContentEncodingKind;
 	features: Set<IPolyfillFeatureInput>;
 	sourcemap: boolean;
diff --git a/src/service/polyfill-builder/polyfill-builder-service.ts b/src/service/polyfill-builder/polyfill-builder-service.ts
index 45920bd..be53e52 100644
--- a/src/service/polyfill-builder/polyfill-builder-service.ts
+++ b/src/service/polyfill-builder/polyfill-builder-service.ts
@@ -215,6 +215,7 @@ export class PolyfillBuilderService implements IPolyfillBuilderService {
 		const {brotli, zlib, raw} = await build({
 			context: request.context,
 			userAgent: request.userAgent,
+			ecmaVersion: request.ecmaVersion,
 			featuresRequested: [...request.features],
 			paths: [...new Set(paths)],
 			features: [...polyfillSet],
diff --git a/src/util/polyfill/polyfill-util.ts b/src/util/polyfill/polyfill-util.ts
index 16db084..85d2db9 100644
--- a/src/util/polyfill/polyfill-util.ts
+++ b/src/util/polyfill/polyfill-util.ts
@@ -10,7 +10,7 @@ import {polyfillRawForceName} from "../../polyfill/polyfill-raw-force-name";
 import {polyfillOptionValueSeparator} from "../../polyfill/polyfill-option-value-separator";
 import {createHash} from "crypto";
 import {constant} from "../../constant/constant";
-import {userAgentSupportsFeatures} from "@wessberg/browserslist-generator";
+import {generateBrowserslistFromUseragent, getAppropriateEcmaVersionForBrowserslist, userAgentSupportsFeatures} from "@wessberg/browserslist-generator";
 import {truncate} from "@wessberg/stringutil";
 import {IPolyfillLibraryDictEntry, IPolyfillLocalDictEntry} from "../../polyfill/polyfill-dict";
 // eslint-disable-next-line @typescript-eslint/ban-ts-ignore
@@ -22,9 +22,6 @@ import {PolyfillCachingContext} from "../../service/registry/polyfill-registry/i
 /**
  * Traces all polyfill names that matches the given name. It may be an alias, and it may refer to additional aliases
  * within the given features
- *
- * @param name
- * @returns
  */
 export function traceAllPolyfillNamesForPolyfillName(name: PolyfillName): Set<PolyfillDealiasedName> {
 	// Get the PolyfillDict that matches the given name
@@ -55,7 +52,7 @@ export function getPolyfillIdentifier(
 	const normalizedName = name instanceof Set ? name : new Set([name]);
 	const sortedName = [...normalizedName].sort((a, b) => (a.name < b.name ? -1 : a.name > b.name ? 1 : 0));
 	const namePart = sortedName.map(part => `${part.name}${JSON.stringify(part.meta)}${context}`).join(",");
-	shasum.update(`[${namePart}].${context.sourcemap}.${context.minify}.${context.encoding || "none"}`);
+	shasum.update(`[${namePart}].${context.sourcemap}.${context.minify}.${context.ecmaVersion}.${context.encoding || "none"}`);
 	return shasum.digest("hex");
 }
 
@@ -181,11 +178,6 @@ export async function getOrderedPolyfillsWithDependencies(polyfillSet: Set<IPoly
 
 /**
  * Generates an IPolyfillRequest from the given URL
- *
- * @param url
- * @param userAgent
- * @param [encoding]
- * @returns
  */
 export function getPolyfillRequestFromUrl(url: URL, userAgent: string, encoding?: ContentEncodingKind): IPolyfillRequest {
 	const featuresRaw = url.searchParams.get("features");
@@ -243,6 +235,7 @@ export function getPolyfillRequestFromUrl(url: URL, userAgent: string, encoding?
 	// Return the IPolyfillRequest
 	return {
 		userAgent,
+		ecmaVersion: getAppropriateEcmaVersionForBrowserslist(generateBrowserslistFromUseragent(userAgent)),
 		encoding,
 		features: featureSet,
 		context,
diff --git a/src/util/type/ecma-version.ts b/src/util/type/ecma-version.ts
new file mode 100644
index 0000000..4c7344c
--- /dev/null
+++ b/src/util/type/ecma-version.ts
@@ -0,0 +1 @@
+export type EcmaVersion = "es3" | "es5" | "es2015" | "es2016" | "es2017" | "es2018" | "es2019" | "es2020";