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What is Appsiel Print Manager?

Appsiel Print Manager (APM) is a robust print management system designed for Point of Sale (POS) environments. It bridges web-based POS applications with thermal and dot matrix printers through a WebSocket server, enabling real-time print job processing and template-based document generation. APM consists of two main components:

Windows Service

Background service that handles WebSocket connections and print job processing on port 7000

MAUI Application

Cross-platform UI for managing printers, templates, and monitoring print jobs

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Key features

WebSocket communication

Real-time bidirectional communication between web clients and the print server

Template-based printing

Flexible JSON templates with support for static sections, tables, and repeated elements

Multiple printer types

Support for thermal (ESC/POS) and dot matrix (ESC/P) printers via TCP, USB, or IPP

Scale integration

Serial scale support for weight-based products with real-time data streaming

Rich document types

Pre-built templates for sales tickets, kitchen orders, invoices, stickers, and more

Remote template updates

Update print templates from web applications without restarting the service

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Architecture overview

APM follows a layered architecture pattern:
The Windows Service runs as a background process, while the MAUI app provides configuration and monitoring capabilities. Both can run independently.

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How it works

1

Client connects

Your web application establishes a WebSocket connection to ws://localhost:7000/websocket/
2

Send print job

Send a PrintJobRequest JSON message containing document type, printer ID, and data
3

Template rendering

APM matches the document type to a template and renders the data using the template sections
4

Command generation

The renderer generates ESC/POS or ESC/P commands based on the printer type
5

Print output

Commands are sent to the printer via the configured connection (TCP, USB, or IPP)
6

Result notification

A PrintJobResult is sent back to the client with success/error status

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Document types

APM includes default templates for common POS documents:
Document TypeDescriptionUse Case
ticket_ventaSales receiptPoint of sale transactions
comandaKitchen orderRestaurant order tickets
factura_electronicaElectronic invoiceFormal invoicing with tax details
sticker_codigo_barrasBarcode stickerProduct labeling
comprobante_egresoPayment voucherCash disbursements
Template definitions are stored as JSON files in the application data folder. Always backup templates before making changes.

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WebSocket message types

APM handles several message types over the WebSocket connection: 
{
  "JobId": "SALE-12345",
  "StationId": "CAJA_1",
  "PrinterId": "printer_main",
  "DocumentType": "ticket_venta",
  "Document": {
    "company": { ... },
    "sale": { ... },
    "footer": []
  }
}
Refer to /home/daytona/workspace/source/Core/Models/PrintJobRequest.cs:1 for the complete model definition.

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Technology stack

.NET 10

Core runtime and libraries

.NET MAUI

Cross-platform UI framework

WebSockets

Real-time communication protocol

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Next steps

Installation

Install the Windows Service and MAUI application

Quick start

Send your first print job in minutes

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