diff --git a/src/common.ts b/src/common.ts
index 1e958d2..4016be2 100644
--- a/src/common.ts
+++ b/src/common.ts
@@ -6,6 +6,7 @@ import { ZqField } from 'ffjavascript'
 
 import poseidon from 'poseidon-lite'
 import { Identity } from '@semaphore-protocol/identity'
+import axios from 'axios'
 
 /*
   This is the "Baby Jubjub" curve described here:
@@ -61,3 +62,37 @@ export function shamirRecovery(x1: bigint, x2: bigint, y1: bigint, y2: bigint):
 export function calculateIdentityCommitment(identitySecret: bigint) {
   return poseidon([identitySecret])
 }
+
+export function isValidUrl(str: string): boolean {
+  try {
+    new URL(str)
+    return true
+  } catch (_) {
+    return false
+  }
+}
+
+export async function checkFileExistsOnWeb(url: string): Promise<boolean> {
+  try {
+    await axios.head(url)
+    return true
+  } catch (error) {
+    return false
+  }
+}
+
+export async function checkFileExists(path: string): Promise<boolean> {
+  if (isValidUrl(path)) {
+    return checkFileExistsOnWeb(path)
+  } else {
+
+    if (typeof process === 'undefined' && typeof window !== 'undefined') {
+      throw new Error(
+        'not allowed to read local files from browser',
+      )
+    }
+
+    const fs = await import('fs')
+    return fs.existsSync(path)
+  }
+}
diff --git a/src/rln.ts b/src/rln.ts
index f73a79e..8ffef06 100644
--- a/src/rln.ts
+++ b/src/rln.ts
@@ -1,6 +1,6 @@
 import { Identity } from '@semaphore-protocol/identity'
 import { VerificationKey } from './types'
-import { DEFAULT_MERKLE_TREE_DEPTH, calculateIdentitySecret, calculateSignalHash } from './common'
+import { DEFAULT_MERKLE_TREE_DEPTH, calculateIdentitySecret, calculateSignalHash, checkFileExists } from './common'
 import { IRLNRegistry, ContractRLNRegistry } from './registry'
 import { MemoryCache, EvaluatedProof, ICache, Status } from './cache'
 import { IMessageIDCounter, MemoryMessageIDCounter } from './message-id-counter'
@@ -224,6 +224,19 @@ export class RLN implements IRLN {
     let wasmFilePath: string | Uint8Array | undefined
     let finalZkeyPath: string | Uint8Array | undefined
     let verificationKey: VerificationKey | undefined
+
+    if (typeof args.wasmFilePath === 'string' && !await checkFileExists(args.wasmFilePath)) {
+      throw new Error(
+        `the file does not exist at the path for \`wasmFilePath\`: wasmFilePath=${args.wasmFilePath}`,
+      )
+    }
+
+    if (typeof args.finalZkeyPath === 'string' && !await checkFileExists(args.finalZkeyPath)) {
+      throw new Error(
+        `the file does not exist at the path for \`finalZkeyPath\`: finalZkeyPath=${args.finalZkeyPath}`,
+      )
+    }
+
     // If `args.wasmFilePath`, `args.finalZkeyPath`, and `args.verificationKey` are not given, see if we have defaults that can be used
     if (args.wasmFilePath === undefined && args.finalZkeyPath === undefined && args.verificationKey === undefined) {
       const defaultParams = await getDefaultRLNParams(treeDepth)
@@ -346,6 +359,19 @@ export class RLN implements IRLN {
     // If all params are not given, use the default
     let withdrawWasmFilePath: string | Uint8Array | undefined
     let withdrawFinalZkeyPath: string | Uint8Array | undefined
+
+    if (typeof args.withdrawWasmFilePath === 'string' && !await checkFileExists(args.withdrawWasmFilePath)) {
+      throw new Error(
+        `the file does not exist at the path for \`withdrawWasmFilePath\`: withdrawWasmFilePath=${args.withdrawWasmFilePath}`,
+      )
+    }
+
+    if (typeof args.withdrawFinalZkeyPath === 'string' && !await checkFileExists(args.withdrawFinalZkeyPath)) {
+      throw new Error(
+        `the file does not exist at the path for \`withdrawFinalZkeyPath\`: withdrawFinalZkeyPath=${args.withdrawFinalZkeyPath}`,
+      )
+    }
+
     // If `args.withdrawWasmFilePath`, `args.finalZkeyPath`, see if we have defaults that can be used
     if (args.withdrawWasmFilePath === undefined && args.withdrawFinalZkeyPath === undefined) {
       const defaultParams = await getDefaultWithdrawParams()
diff --git a/tests/rln.test.ts b/tests/rln.test.ts
index 2049c81..5debc2e 100644
--- a/tests/rln.test.ts
+++ b/tests/rln.test.ts
@@ -74,6 +74,74 @@ describe("RLN", function () {
             );
         });
 
+        test("should fail when wasmFilePath doesn't exist on the web", async function () {
+            const wasmFilePath = "https://rln-trusted-setup-ceremony-pse-p0tion-production.s3.eu-central-1.amazonaws.com/404"
+            const finalZkeyPath = "https://rln-trusted-setup-ceremony-pse-p0tion-production.s3.eu-central-1.amazonaws.com/404"
+            await expect(async () => {
+                await RLN.createWithContractRegistry({
+                    rlnIdentifier: rlnIdentifierA,
+                    treeDepth: treeDepthWithoutDefaultParams,
+                    provider: fakeProvider,
+                    contractAddress: fakeContractAddress,
+                    wasmFilePath: wasmFilePath,
+                    finalZkeyPath: finalZkeyPath
+                });
+            }).rejects.toThrow(
+                `the file does not exist at the path for \`wasmFilePath\`: wasmFilePath=${wasmFilePath}`
+            );
+        });
+
+        test("should fail when finalZkeyPath doesn't exist on the web", async function () {
+            const wasmFilePath = "https://rln-trusted-setup-ceremony-pse-p0tion-production.s3.eu-central-1.amazonaws.com/circuits/rln-20/RLN-20.wasm"
+            const finalZkeyPath = "https://rln-trusted-setup-ceremony-pse-p0tion-production.s3.eu-central-1.amazonaws.com/404"
+            await expect(async () => {
+                await RLN.createWithContractRegistry({
+                    rlnIdentifier: rlnIdentifierA,
+                    treeDepth: treeDepthWithoutDefaultParams,
+                    provider: fakeProvider,
+                    contractAddress: fakeContractAddress,
+                    wasmFilePath: wasmFilePath,
+                    finalZkeyPath: finalZkeyPath
+                });
+            }).rejects.toThrow(
+                `the file does not exist at the path for \`finalZkeyPath\`: finalZkeyPath=${finalZkeyPath}`
+            );
+        });
+
+        test("should fail when wasmFilePath doesn't exist on local", async function () {
+            const wasmFilePath = "./404"
+            const finalZkeyPath = "./404"
+            await expect(async () => {
+                await RLN.createWithContractRegistry({
+                    rlnIdentifier: rlnIdentifierA,
+                    treeDepth: treeDepthWithoutDefaultParams,
+                    provider: fakeProvider,
+                    contractAddress: fakeContractAddress,
+                    wasmFilePath: wasmFilePath,
+                    finalZkeyPath: finalZkeyPath
+                });
+            }).rejects.toThrow(
+                `the file does not exist at the path for \`wasmFilePath\`: wasmFilePath=${wasmFilePath}`
+            );
+        });
+
+        test("should fail when finalZkeyPath doesn't exist on local", async function () {
+            const wasmFilePath = "./package.json"
+            const finalZkeyPath = "./404"
+            await expect(async () => {
+                await RLN.createWithContractRegistry({
+                    rlnIdentifier: rlnIdentifierA,
+                    treeDepth: treeDepthWithoutDefaultParams,
+                    provider: fakeProvider,
+                    contractAddress: fakeContractAddress,
+                    wasmFilePath: wasmFilePath,
+                    finalZkeyPath: finalZkeyPath
+                });
+            }).rejects.toThrow(
+                `the file does not exist at the path for \`finalZkeyPath\`: finalZkeyPath=${finalZkeyPath}`
+            );
+        });
+
         test("should fail to prove if no proving params is given as constructor arguments", async function () {
             const rln = await RLN.createWithContractRegistry({
                 rlnIdentifier: rlnIdentifierA,
diff --git a/tsconfig.json b/tsconfig.json
index 5a87121..299440c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "target": "ES5",
-    "module": "ES6",
+    "module": "ES2020",
     "moduleResolution": "node",
     "allowJs": true,
     "allowSyntheticDefaultImports": true,