GoPLC REST API & Swagger Guide

James M. Belcher Founder, JMB Technical Services LLC April 2026 | GoPLC v1.0.535

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1. Overview

GoPLC exposes 254 REST API endpoints for full control of the PLC runtime — programs, tasks, variables, protocols, diagnostics, clustering, fleet management, and more. Every operation available in the IDE is also available via HTTP.

Access Points

URL	Service
http://host:port/swagger/index.html	Interactive Swagger UI
http://host:port/api/*	REST API
ws://host:port/ws	WebSocket (real-time variable push)
http://host:port/ide/	Web IDE
http://host:port/nodered/	Node-RED (if enabled)

Swagger UI

Open http://localhost:8082/swagger/index.html in a browser. Every endpoint is documented with request/response schemas, parameter descriptions, and a “Try it out” button for live testing.

The Swagger spec is auto-generated from the Go source code annotations and served by the gin-swagger middleware.

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2. API Endpoint Groups

Programs (10)

Method	Endpoint	Description
GET	/api/programs	List all programs
POST	/api/programs	Create or update program
GET	/api/programs/{name}	Get program source
DELETE	/api/programs/{name}	Delete program
POST	/api/programs/{name}/validate	Syntax check without deploy
POST	/api/programs/reload	Reload all programs
POST	/api/programs/clear	Remove all programs
GET	/api/programs/export	Export all as JSON
POST	/api/programs/import	Import from JSON
GET	/api/programs/hash	Current program hash

Tasks (9)

Method	Endpoint	Description
GET	/api/tasks	List all tasks with metrics
POST	/api/tasks	Create task
GET	/api/tasks/{name}	Task detail + scan stats
PUT	/api/tasks/{name}	Update task config
DELETE	/api/tasks/{name}	Delete task
POST	/api/tasks/{name}/start	Start task
POST	/api/tasks/{name}/stop	Stop task
POST	/api/tasks/{name}/reload	Reload task programs
POST	/api/tasks/{name}/download	Download task project

Variables (5)

Method	Endpoint	Description
GET	/api/variables	List all variables with values
GET	/api/variables/{name}	Read single variable
PUT	/api/variables/{name}	Write variable ({"value": ...})
POST	/api/variables/bulk	Bulk read ({"names": [...]})
GET	/api/variables/meta	List variables with metadata

Runtime (10)

Method	Endpoint	Description
GET	/api/runtime	Runtime status
GET	/api/runtime/status	Detailed status
POST	/api/runtime/start	Start runtime
POST	/api/runtime/stop	Stop runtime
POST	/api/runtime/pause	Pause execution
POST	/api/runtime/resume	Resume execution
POST	/api/runtime/restart	Stop + reload + start
GET	/api/runtime/download	Download project as .goplc
POST	/api/runtime/upload	Upload and apply .goplc
GET	/api/runtime/scan-stats	Scan performance metrics

System (8)

Method	Endpoint	Description
GET	/api/info	Version, hostname, OS, uptime
GET	/api/stats	Memory, goroutines
GET	/api/diagnostics	Full diagnostic dump
GET	/api/faults	Active task faults
GET	/api/capabilities	Language features and data types
POST	/api/system/shutdown	Graceful shutdown (SIGTERM)
POST	/api/system/restart	Re-exec process
GET	/api/health	Health check (returns 200)

AI (5)

Method	Endpoint	Description
GET	/api/ai/status	AI availability, provider, model
POST	/api/ai/chat	Chat with AI assistant
POST	/api/ai/control	Autonomous tool-calling (blocking)
POST	/api/ai/control/stream	Autonomous tool-calling (SSE)
GET	/api/ai/capabilities	System prompt stats

HMI (6)

Method	Endpoint	Description
GET	/api/hmi/pages	List HMI pages
POST	/api/hmi/pages	Create HMI page
GET	/api/hmi/pages/{name}	Get page content
PUT	/api/hmi/pages/{name}	Update page
DELETE	/api/hmi/pages/{name}	Delete page
GET	/hmi/{name}	Serve HMI page to browser

Debug (41)

Method	Endpoint	Description
GET	/api/debug/modules	List debug modules and levels
POST	/api/debug/level	Set module log level
GET	/api/debug/buffer	Read log ring buffer
POST	/api/debug/file	Enable file logging
DELETE	/api/debug/file	Disable file logging
POST	/api/debug/db/sqlite	Enable SQLite logging
POST	/api/debug/db/postgres	Enable PostgreSQL logging
GET	/api/debug/db/query	Query log database
POST	/api/debug/influx	Enable InfluxDB logging
GET/POST/DELETE	/api/debug/step/*	Statement-level debugger (breakpoints, step, state)
…	…	(41 total debug endpoints)

Cluster (9) + Cluster Ops (10)

Method	Endpoint	Description
GET	/api/cluster/members	List cluster members
POST	/api/cluster/enable	Promote to boss
POST	/api/cluster/disable	Revert to standalone
POST	/api/cluster/minions	Spawn minion
DELETE	/api/cluster/minions/{name}	Remove minion
GET	/api/cluster/dynamic	Cluster status
ANY	/api/cluster/{name}/*	Proxy to minion API
POST	/api/cluster-ops/export	Export cluster bundle
POST	/api/cluster-ops/import	Import cluster bundle
POST	/api/cluster-ops/reload-all	Reload all nodes

Fleet (16)

Method	Endpoint	Description
GET	/api/fleet/discover	mDNS discovery scan
GET	/api/fleet/nodes	List fleet nodes
PUT	/api/fleet/nodes/{id}	Add/update node
DELETE	/api/fleet/nodes/{id}	Remove node
POST	/api/fleet/nodes/{id}/poll	Poll node
POST	/api/fleet/nodes/{id}/config	Push config
GET	/api/fleet/nodes/{id}/snapshots	Node snapshots
POST	/api/fleet/nodes/{id}/push	Push snapshot
POST	/api/fleet/push-bulk	Push to multiple nodes
GET	/api/fleet/drift	Drift detection
POST	/api/fleet/snapshots/collect	Collect from all nodes
POST	/api/fleet/snapshots/export	Export snapshots
POST	/api/fleet/snapshots/purge	Purge old snapshots
POST	/api/fleet/template/render	Render config template

Snapshots (4)

Method	Endpoint	Description
GET	/api/snapshots	List snapshots
GET	/api/snapshots/history	Snapshot history
GET	/api/snapshots/{hash}	Get specific snapshot
DELETE	/api/snapshots/{hash}	Delete snapshot
POST	/api/snapshots/{hash}/restore	Restore from snapshot

Protocol Analyzer (9)

Method	Endpoint	Description
GET	/api/analyzer	Capture status
POST	/api/analyzer/start	Start capture
POST	/api/analyzer/stop	Stop capture
GET	/api/analyzer/transactions	List captured packets
DELETE	/api/analyzer/transactions	Clear buffer
GET	/api/analyzer/stats	Capture statistics
POST	/api/analyzer/decode	Decode hex packet
GET	/api/analyzer/export/pcap	Download PCAP
GET	/api/analyzer/protocols	Supported protocols

Store-and-Forward (10)

Method	Endpoint	Description
GET	/api/storeforward/status	Queue status
POST	/api/storeforward/store	Store message
POST	/api/storeforward/forward	Forward pending
GET	/api/storeforward/pending	View pending
DELETE	/api/storeforward/clear	Clear queue
GET	/api/storeforward/stats	Queue statistics
POST	/api/storeforward/init	Initialize subsystem
POST	/api/storeforward/close	Shutdown subsystem
POST	/api/storeforward/online	Set network state
POST	/api/storeforward/forward-http	Forward via HTTP

Other Groups

Group	Count	Description
/api/docs/*	2	Function docs and guides
/api/config/*	4	Runtime config read/write
/api/nodered/*	4	Node-RED management (start/stop/restart/status)
/api/license/*	5	License activation and status
/api/libraries/*	5	ST library management
/api/io/*	5	I/O mapping configuration
/api/drivers/*	7	Protocol driver management
/api/serial/*	6	Serial port discovery and management
/api/wizard/*	5	Configuration wizard
/api/project/*	7	Project file management
/api/files/*	2	File upload/download
/api/tags/*	3	Tag browsing
/api/watch/*	2	Variable watch lists
/api/l5x/*	3	Rockwell L5X import/export
/api/logs/*	2	Log ring buffer access
/api/datalayer/*	2	DataLayer status
/api/dl-bridge/*	2	ctrlX Data Layer bridge
/api/pubsub	1	PubSub configuration
/api/agent/deploy	1	AI agent deploy
/api/devices/import-map	1	Device map import
/api/auth/*	1	Authentication status
/api/fuxa/*	1	FUXA SCADA proxy

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3. Authentication

Authentication is optional. When enabled, all API requests require a Bearer token.

Get Token

curl -X POST http://localhost:8082/api/auth/token \
  -H "Content-Type: application/json" \
  -d '{"username": "admin", "password": "password"}'

Response:

{"token": "eyJhbGciOiJIUzI1NiIs..."}

Use Token

curl http://localhost:8082/api/variables \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..."

Configuration

api:
  auth:
    enabled: true
    jwt_secret: ""             # Auto-generated if empty
    token_expiry_hours: 24
    users:
      - username: admin
        password_hash: "$2a$10$..."    # bcrypt hash

When auth is disabled (default), all endpoints are accessible without a token.

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4. WebSocket — Real-Time Variables

Connect to ws://host:port/ws for real-time variable push updates.

Connection

const ws = new WebSocket('ws://localhost:8082/ws');

ws.onopen = () => {
    // Subscribe to specific variables
    ws.send(JSON.stringify({
        subscribe: ['temperature', 'pressure', 'motor_running']
    }));
};

Server Messages

Connected:

{
    "type": "connected",
    "client_id": "ws-001",
    "message": "Send {\"subscribe\": [\"var1\"]} to subscribe"
}

Subscribed confirmation:

{"type": "subscribed", "tags": ["temperature", "pressure"], "timestamp": "..."}

Variable updates (every 100ms default):

{
    "type": "update",
    "data": {
        "temperature": 72.5,
        "pressure": 45.3,
        "motor_running": true
    },
    "timestamp": "2026-04-05T10:30:00Z"
}

Client Commands

Command	Example	Description
Subscribe	{"subscribe": ["var1", "var2"]}	Add variable subscriptions
Unsubscribe	{"unsubscribe": ["var1"]}	Remove subscriptions

Broadcast interval is configurable via api.broadcast_interval in config (default: 100ms).

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5. Common Patterns

Read and Write Variables

# Read all variables
curl http://localhost:8082/api/variables

# Read single variable
curl http://localhost:8082/api/variables/temperature

# Write a variable
curl -X PUT http://localhost:8082/api/variables/setpoint \
  -H "Content-Type: application/json" \
  -d '{"value": 75.0}'

# Bulk read
curl -X POST http://localhost:8082/api/variables/bulk \
  -H "Content-Type: application/json" \
  -d '{"names": ["temperature", "pressure", "flow"]}'

Deploy a Program

# Upload ST code
curl -X POST http://localhost:8082/api/programs \
  -H "Content-Type: application/json" \
  -d '{
    "name": "POU_Control",
    "source": "PROGRAM POU_Control\nVAR\n  counter : INT := 0;\nEND_VAR\n  counter := counter + 1;\nEND_PROGRAM"
  }'

# Reload and start
curl -X POST http://localhost:8082/api/programs/reload
curl -X POST http://localhost:8082/api/runtime/start

Download / Upload Project

# Download current project
curl http://localhost:8082/api/runtime/download -o project.goplc

# Upload project
curl -X POST http://localhost:8082/api/runtime/upload \
  -F "file=@project.goplc"

Check Health

# Simple health check (returns 200 if running)
curl http://localhost:8082/api/health

# Full diagnostics
curl http://localhost:8082/api/diagnostics

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6. Response Formats

Success

{"status": "ok", "message": "Program created"}

Error

{"error": "Program not found: POU_Missing"}

Variable

{
    "name": "temperature",
    "type": "REAL",
    "value": 72.5,
    "scope": "global"
}

Task

{
    "name": "MainTask",
    "state": "running",
    "priority": 1,
    "scan_time_ms": 50,
    "scan_count": 123456,
    "last_scan_us": 45,
    "avg_scan_us": 42,
    "max_scan_us": 312,
    "faulted": false,
    "watchdog_trips": 0
}

Runtime Info

{
    "version": "1.0.535",
    "hostname": "goplc-plant1",
    "os": "linux",
    "arch": "amd64",
    "uptime_seconds": 86400,
    "state": "Running"
}

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Appendix A: Endpoint Count by Group

Group	Count
Debug	41
Fleet	16
Store-Forward	10
Runtime	10
Programs	10
Cluster Ops	10
Tasks	9
Cluster	9
Analyzer	9
System	8
Project	7
Drivers	7
Serial	6
HMI	6
Wizard	5
Variables	5
License	5
Libraries	5
I/O	5
AI	5
Snapshots	5
Config	4
Node-RED	4
Tags	3
L5X	3
All others	21
Total	254

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GoPLC v1.0.535 | 254 REST Endpoints | Swagger UI | WebSocket Real-Time

© 2026 JMB Technical Services LLC. All rights reserved.