3x-ui — Architecture & Code Map

Navigation map for contributors and AI coding agents (referenced from CLAUDE.md). Goal: jump to the right file in one hop instead of grepping the whole tree. Tracks the main branch — paths reflect the latest changes, so verify against the live tree rather than a pinned release (Go module github.com/mhsanaei/3x-ui/v3).

How to use this file: read "Mental model" + "Request lifecycle" first, then use the Symptom → File index to locate work. Respect the Layering rules when adding code. Verify with the commands in Build / Test / Lint.

1. Mental model (the 30-second version)

3x-ui is a web control panel for Xray-core. The Go backend is the source of truth: it stores inbounds/clients/settings in a DB, renders an Xray JSON config from that state, supervises the Xray child process, and exposes a REST + WebSocket API. A React SPA (built by Vite, embedded into the Go binary) is the UI. A second, separate HTTP server serves subscription links to end users.

The panel supervises two managed child processes: Xray-core itself and — when MTProto inbounds exist — the mtg Telegram-proxy binary (internal/mtproto/).

Servers and processes, all launched from main.go:

Server / process	Package	Purpose	Default port
Panel	`internal/web`	Admin REST/WS API + serves the embedded SPA	2053
Subscription	`internal/sub`	Public endpoint that hands out client configs (raw / JSON / Clash)	`subPort` setting
Xray-core	supervised via `internal/xray`	The actual proxy engine; a child process, not Go code	`inbounds[].port`
mtg	supervised via `internal/mtproto`	MTProto proxy child process for MTProto inbounds	per inbound

Two key ideas that explain most of the complexity:

The DB → Xray config pipeline. Inbounds/clients live in the DB. On every change the backend regenerates the Xray config and applies it — preferring a hot diff (live gRPC API mutation) over a full process restart. See §5.1.
The Runtime abstraction (multi-node). A panel can manage remote "nodes" (other 3x-ui instances). Every state-changing inbound/client operation is dispatched through a runtime.Runtime interface that is either Local (this box's Xray gRPC API) or Remote (HTTPS call to a child node, with verify/skip/pin/mtls TLS modes). This is the single most important abstraction in the project. See §5.2.

2. Tech stack

Backend (Go 1.26):

Web framework: Gin (gin-gonic/gin) + sessions (cookie store), gzip.
ORM: GORM with SQLite (default) or PostgreSQL (XUI_DB_TYPE=postgres).
Scheduler: robfig/cron/v3 (seconds-precision) for all background jobs.
Xray: xtls/xray-core vendored as a library; the panel talks to the running core over its gRPC API and also shells out to manage the process.
Telegram bot: mymmrac/telego. i18n: nicksnyder/go-i18n.
Misc: gorilla/websocket, gopsutil (system stats), go-qrcode, gotp (2FA TOTP).

Frontend (frontend/):

React 19 + Ant Design 6 + Vite 8 + TypeScript.
Data layer: TanStack Query (@tanstack/react-query) over axios; Zod 4 schemas.
Router: react-router-dom 7. Charts: recharts. Editor: CodeMirror 6.
Build output goes to internal/web/dist/ (see vite.config.js → outDir) and is embedded into the Go binary with go:embed. Three HTML entries: index.html (panel SPA), login.html, subpage.html. The Go server serves the SPA; there is no separate frontend deployment.

Important: the legacy Go-template UI and web/assets/ are gone. All HTML/JS comes from the embedded Vite dist/. Don't look for .html templates in internal/web.

3. Request lifecycle (follow the data)

3.1 Admin API request (e.g. "add a client")

Browser (React, axios)
  → POST {basePath}/panel/api/...
    → Gin engine (internal/web/web.go: initRouter)
      → middleware chain: SecurityHeaders → MaxBodyBytes (10 MiB; importDB exempt)
                          → [DomainValidator, if webDomain set] → gzip → sessions("3x-ui")
                          → base-path/cache-control context → Localizer
                          → API routes add: ConfigEnvelope (zstd + SHA-256) → CSRF
        → Controller (internal/web/controller/*.go)   // HTTP concerns only: bind, validate, respond
          → Service (internal/web/service/*.go)        // business logic + transactions
            → GORM → DB (internal/database)            // persistence
            → runtime.Runtime dispatch                 // apply to Xray (Local) or node (Remote)
              → Local:  internal/xray (gRPC API or config regen + restart)
              → Remote: internal/web/runtime/remote.go → HTTPS → child node's API

The controller layer is thin. Business logic lives in services. When something is wrong with behavior, the bug is almost always in a service file, not a controller.

3.2 Subscription request (end-user fetching their config)

End user → GET {subPath}/{subId}   (separate server, internal/sub)
  → internal/sub/controller.go (routes: raw / JSON / Clash variants, feature-flagged)
    → internal/sub/service.go (~2.5k lines — the link/config builder)
      → reads inbounds+clients+hosts from DB, renders per-protocol share links /
        Clash YAML / JSON (Host rows can override address/SNI/path per inbound)

3.3 Background work (cron jobs)

Scheduled in internal/web/web.go → startTask(). Each job is a struct in internal/web/job/. Examples: poll Xray traffic every 5s, check client IP limits every 10s, node heartbeat every 5s, periodic traffic resets (hourly/daily/weekly/monthly). See §5.4.

4. Directory map (what lives where)

3x-ui/
├── main.go                     # Entry point: CLI (run / migrate / migrate-db / setting / cert),
│                               #   bootstrap, signal handling, restart loop
├── go.mod / go.sum             # Go deps (module path ends in /v3)
│
├── internal/                   # ALL backend Go code (private packages)
│   ├── config/                 # Env-var config: paths, DB kind/DSN, log level, version
│   │                           #   Every XUI_* env var is read here (config.go)
│   ├── database/
│   │   ├── db.go               # InitDB: connect, AutoMigrate, seeders (~1.4k lines). DB hotspot.
│   │   ├── migrate_data.go     # Data migrations (seeders/normalizers beyond AutoMigrate)
│   │   ├── dialect.go          # SQLite vs Postgres SQL differences
│   │   ├── dump_sqlite.go      # DB export/backup
│   │   └── model/              # **ALL GORM models** (model.go ~1.1k lines + siblings:
│   │                           #   node_client_traffic.go, node_client_ip.go,
│   │                           #   client_global_traffic.go). ⭐ Start here for data shape.
│   ├── eventbus/               # In-process pub/sub (buffered channel): outbound.down|up,
│   │                           #   xray.crash, node.down|up, cpu.high, memory.high, login.attempt
│   ├── tunnelmonitor/          # Optional tunnel health probe (XUI_TUNNEL_HEALTH_* env vars):
│   │                           #   HTTP probe (default Cloudflare trace); repeated failures
│   │                           #   trigger an Xray restart hook. Independent of panel settings.
│   ├── xray/                   # Xray-core integration (the proxy engine wrapper)
│   │   ├── process.go          # Spawn/supervise the Xray child process (~750 lines)
│   │   ├── api.go              # gRPC client to a running Xray (add/remove user, stats) (~800 lines)
│   │   ├── hot_diff.go         # ⭐ Compute minimal live changes to avoid full restart (~500 lines)
│   │   ├── config.go           # Xray config object model
│   │   ├── inbound.go          # Inbound JSON shaping
│   │   ├── client_traffic.go   # ClientTraffic model (persisted as client_traffics)
│   │   ├── traffic.go          # Traffic type helpers
│   │   └── log_writer.go       # Pipe Xray stdout/stderr into the panel logger
│   │
│   ├── web/                    # The panel server
│   │   ├── web.go              # ⭐ Server bootstrap: initRouter (all routes) + startTask (all cron jobs)
│   │   ├── controller/         # HTTP handlers (thin). One file per resource:
│   │   │   ├── inbound.go      #   /panel/api/inbounds
│   │   │   ├── client.go       #   /panel/api/clients (CRUD + bulk + ips + onlines)
│   │   │   ├── group.go        #   client-group endpoints
│   │   │   ├── node.go         #   /panel/api/nodes   (multi-node management)
│   │   │   ├── host.go         #   /panel/api/hosts   (per-inbound subscription host overrides)
│   │   │   ├── server.go       #   /panel/api/server  (status, xray version, certs, logs, DB import/export)
│   │   │   ├── setting.go      #   /panel/api/setting (settings + API tokens)
│   │   │   ├── xray_setting.go #   /panel/api/xray    (raw Xray config editor, WARP/Nord)
│   │   │   ├── api.go          #   /panel/api gateway (token auth, envelope + CSRF wiring)
│   │   │   ├── index.go        #   login/logout/csrf/2FA
│   │   │   ├── spa.go          #   SPA fallback for /panel UI routes
│   │   │   └── websocket.go    #   WS upgrade endpoint
│   │   ├── service/            # ⭐⭐ Business logic. This is where most real work happens.
│   │   │   ├── inbound.go              # Inbound CRUD core (~1.4k lines)
│   │   │   ├── inbound_node.go         # ⭐ Node sync for inbounds: reconcile, traffic merge (~1.1k lines)
│   │   │   ├── inbound_traffic.go      # Per-client traffic accounting (~1.1k lines)
│   │   │   ├── inbound_clients.go      # Client-within-inbound operations
│   │   │   ├── inbound_sublink.go      # Inbound-level subscription link helpers
│   │   │   ├── inbound_migration.go    # Inbound schema/format migrations
│   │   │   ├── client_crud.go          # Client create/read/update/delete
│   │   │   ├── client_bulk.go          # Bulk client ops (~1.6k lines)
│   │   │   ├── client_inbound_apply.go # ⭐ Apply client changes to runtime (Local/Remote) (~1.2k lines)
│   │   │   ├── client_groups.go        # Client grouping
│   │   │   ├── client_link.go          # Per-client share-link generation
│   │   │   ├── client_external_link.go # External links attached to clients
│   │   │   ├── client_wireguard.go     # WireGuard client specifics
│   │   │   ├── client_paging.go        # Server-side pagination/sort/filter for client lists
│   │   │   ├── node.go                 # ⭐ NodeService: CRUD, probe, heartbeat, dirty-tracking (~1.1k lines)
│   │   │   ├── node_mtls.go            # Node mTLS certificate management (master side)
│   │   │   ├── node_tree.go            # Node hierarchy / descendants
│   │   │   ├── host.go                 # Host rows (subscription output overrides)
│   │   │   ├── server.go               # ServerService: status, certs, xray install, DB ops (~2.2k lines)
│   │   │   ├── setting.go              # SettingService: all panel settings + defaults (~1.3k lines)
│   │   │   ├── setting_mtls.go         # mTLS settings (node hardening)
│   │   │   ├── traffic_writer.go       # Batched persistence of traffic deltas to the DB
│   │   │   ├── xray.go                 # ⭐ XrayService: config gen + restart/hot-apply (~1.2k lines)
│   │   │   ├── xray_setting.go         # Raw Xray config persistence
│   │   │   ├── xray_metrics.go         # Xray observability metrics
│   │   │   ├── metric_history.go       # Historical system/xray metrics
│   │   │   ├── reality_scan.go         # REALITY target scanner
│   │   │   ├── url_safety.go           # Outbound URL validation (SSRF guards)
│   │   │   ├── outbound_subscription.go# Outbound subscription (e.g. Warp/Nord provider configs)
│   │   │   ├── port_conflict.go        # Detect inbound port collisions
│   │   │   ├── fallback.go             # Xray fallback (SNI/ALPN routing on shared port)
│   │   │   ├── email/                  # Email notification service (SMTP)
│   │   │   ├── integration/            # External providers: warp.go (Cloudflare WARP), nord.go (NordVPN)
│   │   │   ├── outbound/               # Outbound config service
│   │   │   ├── panel/                  # Cross-cutting panel services:
│   │   │   │   ├── panel.go            #   panel-level helpers
│   │   │   │   ├── user.go             #   admin user auth (bcrypt)
│   │   │   │   ├── api_token.go        #   API token CRUD (SHA-256 hashed)
│   │   │   │   └── websocket.go        #   WS hub / push service
│   │   │   └── tgbot/                  # Telegram bot command handlers
│   │   ├── runtime/            # ⭐⭐ The Local/Remote node abstraction (see §5.2)
│   │   │   ├── runtime.go      #   the Runtime interface (the contract)
│   │   │   ├── local.go        #   Local impl → this box's Xray gRPC API
│   │   │   ├── remote.go       #   Remote impl → HTTPS calls to a child node
│   │   │   ├── tls_client.go   #   per-node HTTP client: verify / skip / pin / mtls
│   │   │   └── manager.go      #   RuntimeFor(nodeID) → picks Local or Remote
│   │   ├── job/               # Cron job structs (one file per job — see §5.4)
│   │   ├── middleware/        # Gin middleware: security.go (headers/HSTS), bodylimit.go,
│   │   │                      #   domainValidator.go, validate.go (CSRF), config_envelope.go
│   │   ├── global/           # Global singletons: web server + sub server handles, restart hook
│   │   ├── network/          # Custom net listeners (e.g. proxy-protocol aware)
│   │   ├── session/          # Session/cookie helpers
│   │   ├── websocket/        # WS hub implementation
│   │   ├── locale/ + translation/  # i18n middleware + 13 locale JSON catalogs
│   │   ├── entity/           # Shared request/response DTOs
│   │   └── dist/             # ⚠️ Vite build output, embedded via go:embed (generated — do not hand-edit)
│   │
│   ├── sub/                   # The subscription server (separate from panel)
│   │   ├── sub.go             #   server bootstrap
│   │   ├── controller.go      #   routes for raw / JSON / Clash subscription formats
│   │   ├── service.go         # ⭐ The link/config builder (~2.5k lines — share-link logic lives here)
│   │   ├── json_service.go    #   JSON subscription format
│   │   ├── clash_service.go   #   Clash/Mihomo YAML format
│   │   ├── clash_external.go  #   external Clash config integration
│   │   ├── external_subscription.go / external_config.go  # external sub import/aggregation
│   │   ├── host_sub.go        #   Host-row overrides applied to subscription output
│   │   ├── endpoint.go        #   subscription endpoint configuration
│   │   ├── vless_route.go     #   VLESS route shaping
│   │   ├── remark_vars.go     #   remark variable expansion
│   │   └── links.go           #   link helpers
│   │
│   ├── mtproto/              # Embedded MTProto (Telegram) proxy: manager.go + per-OS
│   │                         #   process supervision + orphan cleanup
│   ├── logger/              # App logger (op/go-logging + lumberjack rotation)
│   └── util/                # Leaf helpers (no business logic):
│       ├── common/          #   errors, misc
│       ├── crypto/          #   key/cert generation (x25519, ML-KEM/ML-DSA, ECH)
│       ├── link/            #   outbound share-link building primitives
│       ├── wirecodec/ + wireguard/  # WireGuard codec + integration helpers
│       └── random/, json_util/, reflect_util/, sys/, netproxy/, netsafe/, ldap/
│
├── frontend/                 # React SPA (built into internal/web/dist)
│   ├── vite.config.js        # ⭐ Build config: outDir → ../internal/web/dist, dev on :5173
│   │                         #   (strict) proxying to :2053, entries index/login/subpage.html
│   ├── package.json          # scripts: dev / build / preview / lint / typecheck / test / gen
│   └── src/
│       ├── main.tsx / routes.tsx / queryClient.ts   # SPA entry, router, query client
│       ├── entries/          # Extra HTML entry points: login.tsx, subpage.tsx
│       ├── pages/            # ⭐ Route screens. Mirrors the panel's feature areas:
│       │   ├── inbounds/     #   inbound list + the big inbound form (protocols/security/transport)
│       │   ├── clients/      #   client management screens
│       │   ├── nodes/        #   multi-node UI
│       │   ├── hosts/        #   subscription host-override UI
│       │   ├── xray/         #   raw Xray config UI (routing, dns, outbounds, balancers, overrides)
│       │   ├── index/        #   dashboard/home
│       │   └── settings/, groups/, sub/, login/, api-docs/
│       ├── api/              # ⭐ Data layer: axios-init, QueryProvider, queryKeys, websocket bridge
│       │   └── queries/      #   TanStack Query hooks (useNodesQuery, useStatusQuery, …)
│       ├── schemas/          # Zod schemas: protocols, forms, api, primitives
│       ├── generated/        # ⚠️ GENERATED from Go (see §5.5): schemas.ts, types.ts, zod.ts, examples.ts
│       ├── components/       # Reusable UI (clients/ form/ ui/ viz/ feedback/ utility/)
│       ├── lib/              # Frontend domain logic (xray/ inbounds/ clients/)
│       ├── hooks/, models/, layouts/, i18n/, utils/, styles/
│       └── test/             # Vitest + golden fixtures (config-generation snapshot tests)
│
├── tools/openapigen/         # ⭐ Go program that emits frontend/src/generated/* from Go types (§5.5)
├── docs/                     # Markdown docs (this file, custom-subscription-templates.md, …)
├── media/                    # README images
│
├── Dockerfile / docker-compose.yml / DockerEntrypoint.sh / DockerInit.sh   # Container build/run
├── install.sh / update.sh / x-ui.sh                        # VPS install + management CLI
├── x-ui.service.*  / x-ui.rc                               # systemd units (debian/rhel/arch) + rc script
├── windows_files/                                          # Windows service support
└── .github/workflows/        # CI: ci.yml, codeql.yml, docker.yml, release.yml, smoke.yml,
                              #     mutation.yml, cleanup_caches.yml, claude-bot.yml

5. Cross-cutting subsystems (the parts that span many files)

5.1 DB → Xray config pipeline (config generation & application)

The panel never edits Xray's running config directly from controllers. The flow is:

A service mutates DB state (inbound/client/setting).
XrayService (service/xray.go) builds a fresh xray.Config from DB state (GetXrayConfig).
It tries a hot apply (tryHotApply → xray/hot_diff.go): diff old vs new config and push only the deltas over the Xray gRPC API (add/remove inbound, add/remove user) — no process restart, so live connections survive.
If the diff isn't hot-applicable (structural change), it falls back to a full restart of the Xray process (xray/process.go).

Restart is debounced via an atomic "need restart" flag (SetToNeedRestart / IsNeedRestartAndSetFalse), consumed by a @every 30s cron task registered in startTask() — any number of mutations inside the window causes at most one restart.

Key files: service/xray.go (orchestration), xray/hot_diff.go (the diff algorithm), xray/process.go (process lifecycle), xray/api.go (gRPC calls), xray/config.go (config model).

5.2 Runtime abstraction — Local vs Remote (multi-node) ⭐ most important

A "node" (model.Node) is another 3x-ui instance this panel controls. Every state-changing inbound/client operation goes through the runtime.Runtime interface so the same service code works whether the target is the local Xray or a remote node.

Interface: internal/web/runtime/runtime.go — Name, AddInbound, DelInbound, UpdateInbound, AddUser, RemoveUser, UpdateUser, DeleteUser, AddClient, RestartXray, ResetClientTraffic, ResetInboundTraffic, ResetAllTraffics.
Local (local.go): calls this box's Xray gRPC API directly.
Remote (remote.go): serializes the operation and sends it over HTTPS to the child node's API.
TLS modes (tls_client.go, per-node TlsVerifyMode): verify (system CAs, default) / skip (no validation) / pin (leaf cert SHA-256 must match PinnedCertSha256) / mtls (master presents a client certificate; node cert checked against system roots; API token optional). Master-side cert management: service/node_mtls.go + service/setting_mtls.go.
Dispatch: manager.go → Manager.RuntimeFor(nodeID *int); nil nodeID → Local, otherwise a cached/lazy-loaded Remote. InvalidateNode(id) drops a cached remote client.

Node identity & attribution (the hard part). Inbounds carry a NodeID and an OriginNodeGuid. Because inbounds can be pushed across hops, the panel attributes traffic and online clients back to the originating panel using stable GUIDs rather than local IDs. Relevant logic: service/inbound_node.go (ReconcileNode, SetRemoteTraffic, GUID merge, synthNodeGuid, panelGuid) and service/node.go (effectiveNodeGuid, heartbeat, dirty tracking). Node "dirty" flags drive an anti-entropy reconciliation so an offline node's inbound edits converge once it reconnects.

Where to look for node bugs:

Operation not reaching a node → runtime/remote.go + runtime/manager.go.
Wrong traffic/online attribution across hops → service/inbound_node.go (GUID merge paths).
Node shown offline / stale status → job/node_heartbeat_job.go + service/node.go (Probe, UpdateHeartbeat).
Edits to an offline node not applying on reconnect → dirty/reconcile logic in service/inbound_node.go + service/node.go (MarkNodeDirty/ClearNodeDirty/NodeSyncState).
TLS/mTLS handshake failures → runtime/tls_client.go, service/node_mtls.go, service/node.go (FetchCertFingerprint).

5.3 Traffic accounting

Per-client and per-inbound up/down counters originate from Xray's stats API and are persisted to the DB. The Xray traffic job polls the core; node traffic is pulled from child nodes and merged with GUID-based baselines to avoid double counting after resets.

Key files: service/inbound_traffic.go, service/traffic_writer.go, job/xray_traffic_job.go, job/node_traffic_sync_job.go, service/inbound_node.go (SetRemoteTraffic / upsertNodeBaseline), models xray.ClientTraffic, model.NodeClientTraffic, model.ClientGlobalTraffic (cross-master totals). Periodic resets: job/periodic_traffic_reset_job.go (keyed off Inbound.TrafficReset).

5.4 Background jobs (cron)

All registered in web.go → startTask(). Each is a struct with a Run() method in internal/web/job/:

Schedule	Job	Purpose / condition
`@every 1s`	`check_xray_running_job`	Restart Xray if it died (2 consecutive down checks)
`@every 30s`	(inline func in `startTask`)	Debounced Xray restart — consumes the "need restart" flag (§5.1)
`@every 5s`	`xray_traffic_job`	Pull traffic stats from Xray (5s start delay)
`@every 5s`	`node_heartbeat_job`	Probe child nodes (online/offline)
`@every 5s`	`node_traffic_sync_job`	Pull + merge node traffic; push reconciliation
`@every 10s`	`check_client_ip_job`	Enforce per-client IP limits
`@every 10s`	`mtproto_job`	Reconcile `mtg` sidecars against enabled MTProto inbounds
`@every 5m`	`outbound_subscription_job`	Refresh outbound provider configs
`@hourly`	`warp_ip_job`, `periodic_traffic_reset_job("hourly")`	WARP IP rotation; traffic resets
`@daily`	`clear_logs_job`, `periodic_traffic_reset_job("daily")`	Log cleanup; resets
`@weekly` / `@monthly`	`periodic_traffic_reset_job(...)`	Weekly/monthly traffic resets
default `@every 1m`	`ldap_sync_job`	Only if LDAP enabled; schedule configurable
default `@daily`	`stats_notify_job`	Only if TG bot enabled; schedule configurable
`@every 2m`	`check_hash_storage`	Only if TG bot enabled; expires bot callback hashes
`@every 1m`	`check_cpu_usage`	Only if a CPU alarm is configured (TG or email); publishes `cpu.high`
`@every 1m`	`check_memory_usage`	Only if a memory alarm is configured; publishes `memory.high`
configurable	`free_os_memory`	Only if `sys.MemoryReleaseIntervalMinutes() > 0`; returns heap to OS

To change when something runs, edit startTask(). To change what it does, edit the job file.

5.5 Type generation (Go → TypeScript) ⚠️ don't hand-edit generated files

The Go backend is the schema source of truth. tools/openapigen (a Go program, with a StructAllow allowlist of exported types) emits frontend/src/generated/{schemas,types,zod,examples}.ts. The frontend build runs this first:

npm run gen:zod → go run ./tools/openapigen (regenerate from Go)
npm run gen:api → builds the OpenAPI doc (scripts/build-openapi.mjs, driven by the hand-maintained endpoint registry src/pages/api-docs/endpoints.ts)
npm run build runs gen:api then vite build.

Implication: if you change a Go model/DTO that crosses the API boundary, regenerate the frontend types (cd frontend && npm run gen) instead of editing src/generated/ by hand.

5.6 Share-link / subscription generation

Two distinct code paths produce client configs:

Per-client links in the panel (the "copy link" / QR in the UI): service/client_link.go
- util/link/outbound.go.
Subscription endpoint (what a client app polls): internal/sub/service.go (raw links), internal/sub/json_service.go (JSON), internal/sub/clash_service.go (Clash YAML). Host rows (model.Host, edited under /panel/api/hosts) override address/SNI/path/ security per inbound in subscription output — applied in sub/host_sub.go.

Both paths must agree per protocol. A malformed link for a specific protocol/transport combo (e.g. XHTTP + Reality) is usually a field-lookup mismatch in internal/sub/service.go (and its tests service_test.go / golden fixtures), or in util/link/outbound.go. The frontend also has protocol schemas under frontend/src/schemas/protocols/ and frontend/src/lib/xray/.

5.7 Event bus (in-process pub/sub)

internal/eventbus/ is a minimal buffered-channel pub/sub. Producers call a non-blocking Publish(Event); all subscribers receive every event. Event types: outbound.down|up, xray.crash, node.down|up, cpu.high, memory.high, login.attempt, with structured payloads (OutboundHealthData, NodeHealthData, LoginEventData, SystemMetricData). Producers include the CPU/memory jobs, node heartbeat, and login handling; consumers include the Telegram bot and the email notifier (service/email/). Use it for cross-cutting notifications instead of importing notification services into producers.

5.8 Tunnel health monitor

internal/tunnelmonitor/ is an optional watchdog configured only via env vars (XUI_TUNNEL_HEALTH_*, read in internal/config/), deliberately independent of panel settings so it can be enabled from a systemd EnvironmentFile even when the panel is unreachable. It periodically probes an HTTP URL (default: Cloudflare trace endpoint) through the tunnel; after N successive failures (default 3) it fires a recovery callback wired to an Xray restart.

6. Data model cheat-sheet

GORM models in internal/database/model/ (main file model.go + siblings); all registered for AutoMigrate in internal/database/db.go.

Model	Table role	Notable fields
`User`	Admin login	bcrypt password, `LoginEpoch` (invalidates sessions)
`Inbound`	An Xray inbound	`Tag` (unique), `Port`, `Protocol`, `Settings`/`StreamSettings`/`Sniffing` (JSON), `Enable`, `TrafficReset`, `NodeID`, `OriginNodeGuid`, `ClientStats` (assoc)
`Client`	In-memory client view	UUID/email/flow/limits (parsed from inbound JSON; not persisted)
`ClientRecord`	Persisted client (`clients`)	`Email` (unique), `SubID`, `UUID`, `TotalGB`, `ExpiryTime`, `LimitIP`, `Group`, `Reset`
`ClientGroup` / `ClientInbound`	Grouping + client↔inbound join	many-to-many wiring, `FlowOverride`
`ClientExternalLink`	Extra links attached to a client	`Kind`, `Value`, `Remark`, `SortIndex`
`Host`	Subscription host overrides (per inbound)	`Address`, `Port`, `Sni`, `Path`, `Security`, `Fingerprint`, `SortOrder`, visibility/exclusion flags
`Node`	A managed child panel	`Guid`, `Address`, `Status`, `TlsVerifyMode`, `PinnedCertSha256`, `ConfigDirty`, version/heartbeat/metric fields
`NodeClientTraffic`	Per-node client traffic baseline	cross-node merge (anti-double-count)
`NodeClientIp`	Per-node client IP attribution	`NodeGuid`, `Email`, `Ips`
`ClientGlobalTraffic`	Cross-master usage totals	`MasterGuid`, `Email`, `Up`, `Down`
`xray.ClientTraffic`	Per-client counters (`client_traffics`)	`Email`, `Up`, `Down`, `Total`, `ExpiryTime`, `LastOnline`
`InboundClientIps`	IP set per client email	drives IP-limit enforcement
`OutboundTraffics`	Outbound counters	per outbound tag
`OutboundSubscription`	External provider subs	Warp/Nord style
`Setting`	Key/value panel settings	everything configurable
`ApiToken`	REST API tokens	SHA-256 hash (plaintext shown once)
`InboundFallback`	Fallback routing on a shared port	SNI/ALPN/path → dest
`HistoryOfSeeders`	Seeder bookkeeping	prevents re-running one-off migrations

7. Symptom → File index (start here when debugging)

Symptom / task	Primary file(s)	Then check
Add/modify an API endpoint	`controller/<resource>.go` (route registration at top of each file)	corresponding `service/*.go`, `frontend/src/pages/api-docs/endpoints.ts`
Inbound create/update/delete behavior	`service/inbound.go`, `service/inbound_clients.go`	`runtime/*`, `service/xray.go`
Client CRUD / limits / expiry	`service/client_crud.go`, `service/client_inbound_apply.go`	model `ClientRecord`, `service/inbound_traffic.go`
Bulk client operations slow/wrong	`service/client_bulk.go`	`service/client_paging.go`
Xray won't apply a config change	`service/xray.go` (`RestartXray`, `tryHotApply`)	`xray/hot_diff.go`, `xray/process.go`
Xray restarts when it shouldn't (kills connections)	`xray/hot_diff.go` (diff not classified as hot)	`service/xray.go`
Traffic counts wrong / reset behavior	`service/inbound_traffic.go`, `job/xray_traffic_job.go`	`service/traffic_writer.go`, `job/periodic_traffic_reset_job.go`
Node operation not propagating	`runtime/remote.go`, `runtime/manager.go`	`service/inbound_node.go`
Multi-hop / cross-node attribution (traffic or online clients on wrong panel)	`service/inbound_node.go` (GUID merge, `synthNodeGuid`, `effectiveNodeGuid`)	`service/node.go`, model `OriginNodeGuid`/`Node.Guid`
Node stuck offline / stale	`job/node_heartbeat_job.go`, `service/node.go` (`Probe`, `UpdateHeartbeat`)	`runtime/tls_client.go` (TLS verify)
Node TLS / mTLS auth failures	`runtime/tls_client.go`, `service/node_mtls.go`, `service/setting_mtls.go`	`service/node.go` (`FetchCertFingerprint`)
Offline node edits not reconciling on reconnect	`service/inbound_node.go` (`ReconcileNode`, dirty flags)	`service/node.go` (`MarkNodeDirty`/`NodeSyncState`)
Share link / QR malformed (per protocol)	`service/client_link.go`, `util/link/outbound.go`	`frontend/src/lib/xray/`, `frontend/src/schemas/protocols/`
Subscription output wrong (raw/JSON/Clash)	`internal/sub/service.go`	`sub/json_service.go`, `sub/clash_service.go`, sub golden tests
Subscription host overrides not applied	`service/host.go`, `sub/host_sub.go`	model `Host`, `frontend/src/pages/hosts/`
External subscription import/aggregation	`sub/external_subscription.go`, `sub/external_config.go`	`sub/clash_external.go`
Settings not saving / defaults	`service/setting.go`, `controller/setting.go`	model `Setting`
Login / 2FA / sessions / CSRF	`controller/index.go`, `service/panel/user.go`, `middleware/`	`session/`
API tokens	`service/panel/api_token.go`, `controller/setting.go`	model `ApiToken`
Port conflict on inbound add	`service/port_conflict.go`	`controller/inbound.go`
Fallbacks (shared 443, SNI routing)	`service/fallback.go`, `controller/inbound.go`	model `InboundFallback`
Telegram bot commands	`service/tgbot/`	`job/stats_notify_job.go`
Email notifications	`service/email/`	`internal/eventbus/` (consumers)
CPU / memory alerts not firing	`job/check_cpu_usage.go`, `job/check_memory_usage.go`	`internal/eventbus/`, notifier settings in `service/setting.go`
Xray auto-restart on dead tunnel	`internal/tunnelmonitor/`	`XUI_TUNNEL_HEALTH_*` in `internal/config/`
WARP / Nord outbound integration	`service/integration/warp.go` / `nord.go`	`service/outbound_subscription.go`
MTProto proxy issues	`internal/mtproto/manager.go`, `mtproto/process*.go`	`job/mtproto_job.go`
DB migration / new column	`internal/database/db.go` (AutoMigrate list), `migrate_data.go`	`model/model.go`
Cron schedule changes	`web.go` → `startTask()`	the specific `job/*.go`
CORS / security headers / HTTPS	`middleware/`, `web.go` (`initRouter`, TLS setup)	`config/` (env)
Env vars / paths / DB type	`internal/config/config.go`	`.env.example`
Frontend route / screen	`frontend/src/pages/<area>/`, `frontend/src/routes.tsx`	`frontend/src/api/queries/`
Frontend ↔ backend type mismatch	regenerate: `cd frontend && npm run gen` (`tools/openapigen`)	`frontend/src/generated/`
System status / CPU / metrics	`service/server.go`, `service/xray_metrics.go`, `service/metric_history.go`	`controller/server.go`, gopsutil

8. Layering rules (where new code belongs)

Controllers are thin. Only: bind/validate input, call one service, shape the HTTP response. No DB queries, no Xray calls, no business rules in controller/.
Services own the logic and transactions. All business rules, DB access, and decisions about applying changes live in service/. If you're tempted to query GORM from a controller, move it to a service.
Never touch Xray's running state from a controller or job directly. Go through XrayService / the runtime.Runtime interface so local vs node dispatch stays correct.
Any state-changing inbound/client op must dispatch through runtime.Runtime, not straight to xray/api.go — otherwise node deployments silently break.
internal/util/* is leaf-only (no imports of service/controller/database). Keep helpers pure.
Don't hand-edit generated files: frontend/src/generated/* and internal/web/dist/*. Regenerate instead.
Models are the contract. Changing a model field that crosses the API boundary means: update model.go → handle migration in db.go/migrate_data.go → regenerate frontend types.
Two servers, two concerns. Admin features go in internal/web; anything an end user fetches goes in internal/sub. Don't blur them.
Cross-cutting notifications go through internal/eventbus/ — publish an event instead of importing the Telegram/email services into producers.

9. Build / Test / Lint (verify your changes)

The canonical gate is the Makefile (mirrors CI): make verify. Also: make gen (regenerate Zod/OpenAPI), make lint (Go + frontend), make test (Go -shuffle=on + frontend), make race, make build. Run make help for everything. Raw commands:

Backend (Go):

go build ./...                      # compile everything
go test ./...                       # run all Go tests (many *_test.go alongside sources)
go test ./internal/web/service/...  # focused: service-layer tests
go test ./internal/xray/...         # hot-diff / process / api tests
go test ./internal/sub/...          # subscription + golden link tests
go vet ./...                        # static checks
golangci-lint run                   # full lint (gofumpt + goimports formatting)
go run main.go                      # run the panel locally (serves embedded dist if built)

Frontend (cd frontend, Node ≥ 22):

npm install
npm run dev          # Vite dev server on :5173; proxies API to Go backend on :2053 (run `go run main.go` too)
npm run typecheck    # tsc --noEmit
npm run lint         # eslint src
npm run test         # vitest (incl. golden config-generation snapshots)
npm run gen          # regenerate src/generated/* from Go (gen:zod + gen:api)
npm run build        # gen:api + vite build → outputs to internal/web/dist (then rebuild Go binary to embed)

Full local loop: cd frontend && npm run build (refresh embedded dist/) → back to repo root → go build ./... / go run main.go.

Docker: docker compose up -d (uses Dockerfile + DockerEntrypoint.sh).

CI (.github/workflows/): ci.yml (build/test/lint), codeql.yml (security scan), smoke.yml (smoke tests), mutation.yml (mutation testing), docker.yml + release.yml (multi-arch image + release builds), cleanup_caches.yml, claude-bot.yml (issue bot).

10. Gotchas & conventions

Module path is .../v3. Internal imports use github.com/mhsanaei/3x-ui/v3/internal/....
SQLite vs Postgres. Default is SQLite at {XUI_DB_FOLDER}/x-ui.db. Postgres via XUI_DB_TYPE=postgres + XUI_DB_DSN. Some SQL paths are dialect-aware (database/dialect.go); test both when touching raw queries (there are *_scale_postgres_test.go suites).
Inbound.Settings / StreamSettings / Sniffing are raw JSON strings, not structured columns. Parsing/validation happens in services and the xray package, not in GORM.
Hot-reload is the default; full restart is the fallback. Changes that look config-only but cause a restart usually mean the diff in xray/hot_diff.go didn't recognize them as hot.
Node TLS: remote calls honor TlsVerifyMode (verify/skip/pin/mtls). "Works on skip, fails on verify/pin/mtls" → cert/fingerprint handling in service/node.go (FetchCertFingerprint), service/node_mtls.go, and runtime/tls_client.go.
Restart is signal-driven. main.go traps SIGHUP to restart panel+sub servers; the in-process restart hook (global.SetRestartHook) funnels into the same path.
i18n: backend catalogs in internal/web/translation/ (13 locales, shared with the frontend); frontend wiring in frontend/src/i18n/. Persian (fa_IR) is a first-class locale (Jalali calendar via persian-calendar-suite).
Tests live next to code (foo.go ↔ foo_test.go), plus golden snapshots in frontend/src/test/golden/fixtures/ for config generation — update fixtures intentionally, not blindly, when output changes.

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