Wails3 dev cannot connect to frontend server that is already running
Author: MrkouhadiCreated Jan 25, 2026Updated Sep 10, 2026
LabelsBugWIPv3P1
DESCRIPTION
When running wails3 dev on a freshly created Wails v3 project, the application fails to start. Despite the frontend being live and reachable, Wails it cannot connect to the frontend server.
I believe it's related to ESBUILD
SYSTEM HEALTH
wails3 doctor
Wails (v3.0.0-alpha.62) Wails Doctor
# System
┌─────────────────────────────────────────────────┐
| Name | MacOS |
| Version | 14.7.4 |
| ID | 23H420 |
| Branding | Sonoma |
| Platform | darwin |
| Architecture | arm64 |
| Apple Silicon | true |
| CPU | Apple M1 |
| CPU 1 | Apple M1 |
| CPU 2 | Apple M1 |
| GPU | 8 cores, Metal Support: Metal 3 |
| Memory | 16 GB |
└─────────────────────────────────────────────────┘
# Build Environment
┌────────────────────────────────┐
| Wails CLI | v3.0.0-alpha.62 |
| Go Version | go1.25.4 |
| -buildmode | exe |
| -compiler | gc |
| CGO_CFLAGS | |
| CGO_CPPFLAGS | |
| CGO_CXXFLAGS | |
| CGO_ENABLED | 1 |
| CGO_LDFLAGS | |
| GOARCH | arm64 |
| GOARM64 | v8.0 |
| GOOS | darwin |
└────────────────────────────────┘
# Dependencies
┌──────────────────────────────────────────────────────────────────────────────┐
| Xcode cli tools | 2408 |
| npm | 10.2.3 |
| *NSIS | v3.11 |
| docker | *Docker version 27.4.0, build bde2b89 (daemon not running) |
| |
└────────────────────────── * - Optional Dependency ───────────────────────────┘
# Checking for issues
SUCCESS No issues found
# Diagnosis
SUCCESS Your system is ready for Wails development!
Need documentation? Run: wails3 docs
♥ If Wails is useful to you or your company, please consider sponsoring the project: wails3 sponsorERROR LOG
4:21PM INF Build Info: Wails=v3.0.0-alpha.62 Compiler=go1.25.4 -gcflags="all=-l" CGO_ENABLED=1 CGO_CPPFLAGS="" CGO_CXXFLAGS="" GOARCH=arm64 -buildmode=exe CGO_CFLAGS="-mmacosx-version-min=10.15" CGO_LDFLAGS="-mmacosx-version-min=10.15" GOOS=darwin GOARM64=v8.0 -compiler=gc
4:21PM INF Platform Info: ID=23H420 Name=MacOS Version=14.7.4 Branding=Sonoma
4:21PM INF AssetServer Info: middleware=true handler=true devServerURL=http://localhost:9245
4:21PM INF Waiting for frontend dev server to start... url=http://localhost:9245
task: [common:install:frontend:deps] npm install
4:21PM INF Retrying... reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
4:21PM INF Retrying... reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
4:21PM INF Retrying... reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
4:21PM INF Retrying... reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
4:21PM INF Retrying... reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
4:21PM ERR ########) ⠋ reify:@esbuild/aix-ppc64: timing reifyNode:node_modules/
******************************** FATAL *********************************
* There has been a catastrophic failure in your application. *
**************************** Error Details *****************************
unable to connect to frontend server. Please check it is running - FRONTEND_DEVSERVER_URL='http://localhost:9245'
************************************************************************
ERROR task: Failed to run task "run": exit status 1
2026/01/25 16:21:17 ERROR Could not refresh processes due to execution errors
task: [common:dev:frontend] npm run dev -- --port 9245 --strictPortSource: wailsapp/wails