diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000000..5cb534cc8e
--- /dev/null
+++ b/.envrc
@@ -0,0 +1,7 @@
+if ! has nix_direnv_version || ! nix_direnv_version 3.0.5; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.5/direnvrc" "sha256-RuwIS+QKFj/T9M2TFXScjBsLR6V3A17YVoEW/Q6AZ1w="
+fi
+
+use nix
+watch_file flake.nix
+watch_file flake.lock
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000000..86ed220ac2
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,25 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1721379653,
+        "narHash": "sha256-8MUgifkJ7lkZs3u99UDZMB4kbOxvMEXQZ31FO3SopZ0=",
+        "rev": "1d9c2c9b3e71b9ee663d11c5d298727dace8d374",
+        "revCount": 655136,
+        "type": "tarball",
+        "url": "https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.655136%2Brev-1d9c2c9b3e71b9ee663d11c5d298727dace8d374/0190cd4f-c0eb-72cb-834b-ac854aa282dc/source.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://flakehub.com/f/NixOS/nixpkgs/0.1.%2A.tar.gz"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000000..1154860a30
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,25 @@
+{
+  description = "A Nix-flake-based Node.js development environment";
+
+  inputs.nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0.1.*.tar.gz";
+
+  outputs = { self, nixpkgs }:
+    let
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      forEachSupportedSystem = f: nixpkgs.lib.genAttrs supportedSystems (system: f {
+        pkgs = import nixpkgs { inherit system; overlays = [ self.overlays.default ]; };
+      });
+    in
+    {
+      overlays.default = final: prev: rec {
+        nodejs = prev.nodejs;
+        yarn = (prev.yarn.override { inherit nodejs; });
+      };
+
+      devShells = forEachSupportedSystem ({ pkgs }: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [ node2nix nodejs nodePackages.pnpm yarn ];
+        };
+      });
+    };
+}
diff --git a/package.json b/package.json
index b826dc8d2c..a69ccda794 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,8 @@
   "resolutions": {
     "**/@walletconnect/ethereum-provider": "2.13.1",
     "**/@ethersproject/providers/ws": "7.5.10",
-    "**/@synthetixio/synpress/ws": "8.17.1"
+    "**/@synthetixio/synpress/ws": "8.17.1",
+    "**/@arbitrum/sdk": "https://github.com/EspressoSystems/arbitrum-sdk/releases/download/v5.0.0-pre/espressosystems-arbitrum-sdk-v4.0.1.tgz"
   },
   "keywords": [],
   "author": "",
diff --git a/packages/arb-token-bridge-ui/src/util/networks.ts b/packages/arb-token-bridge-ui/src/util/networks.ts
index 1ffc2ffede..92763c4ffe 100644
--- a/packages/arb-token-bridge-ui/src/util/networks.ts
+++ b/packages/arb-token-bridge-ui/src/util/networks.ts
@@ -285,7 +285,7 @@ export const defaultL2Network: ArbitrumNetwork = {
     outbox: '0x50143333b44Ea46255BEb67255C9Afd35551072F',
     rollup: process.env.NEXT_PUBLIC_IS_E2E_TEST
       ? '0xE8A8F50F2a237D06D0087D14E690f6Ff0556259D'
-      : '0x46966d871d29e1772c2809459469f849d8AAb1A3',
+      : '0x9E7027f19AE93681f5A2cb2d87841a7e1E3Cdbe7',
     sequencerInbox: '0x18d19C5d3E685f5be5b9C86E097f0E439285D216'
   },
   isCustom: true,
diff --git a/yarn.lock b/yarn.lock
index a84ce59fbe..af4ac799f2 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -44,10 +44,9 @@
     tslib "^2.3.0"
     zen-observable-ts "^1.2.5"
 
-"@arbitrum/sdk@^4.0.1":
+"@arbitrum/sdk@^4.0.1", "@arbitrum/sdk@https://github.com/EspressoSystems/arbitrum-sdk/releases/download/v5.0.0-pre/espressosystems-arbitrum-sdk-v4.0.1.tgz":
   version "4.0.1"
-  resolved "https://registry.yarnpkg.com/@arbitrum/sdk/-/sdk-4.0.1.tgz#b51c7bb8ecef0143a35b7f3ab8538031bb1830d2"
-  integrity sha512-uW0Pe/oICbmlHpIpYOaHHWsNQRG+3UbCa3s0SJsp2O1Kt9b0M0CX/fEdFOFLyAi3OxHonNEfzhfvQrALy9C3Yw==
+  resolved "https://github.com/EspressoSystems/arbitrum-sdk/releases/download/v5.0.0-pre/espressosystems-arbitrum-sdk-v4.0.1.tgz#42eb09129d1deab205e235be0c7dd7a19ce29418"
   dependencies:
     "@ethersproject/address" "^5.0.8"
     "@ethersproject/bignumber" "^5.1.1"