EPLPrinter Web API for Docker

Convert, Preview & Render EPL commands to PNG, JPG & PDF from Docker!

EPLPrinter Web API for Docker allows you to Convert, Preview and Render raw EPL (Zebra/Eltron Programming Language) commands to well known image and document formats like PNG, JPG, PDF, PCX, Zebra GRF ASCII hex, Zebra EPL Binary Graphic, Honeywell-Intermec FingerPrint Binary Graphic, HP PCL Binary Graphic & EPSON ESC/POS NV Binary Graphic from Any Development Platform and Programming Languages (.NET, Java, PHP, Javascript, Python, Ruby, and more!) with a single HTTP POST.

It ships as a Linux Docker image for amd64 and arm64 that you run on your own servers, Kubernetes cluster or cloud account, so your EPL and label data never leave your infrastructure. It can also convert EPL to ZPL so legacy EPL applications keep printing on ZPL-only Zebra printers. If you prefer an in-process library for .NET, see the EPLPrinter Emulator SDK for .NET.

Features at a Glance

Overview

Designed by following some of the REST principles, EPLPrinter Web API for Docker responds to a simple HTTP POST by specifying the EPL commands and printer settings through a JSON object in the request body, returning the output rendering in the image or document format specified through the Accept header.

Help Doc Topics

Download and run EPLPrinter Web API for Docker

EPLPrinter Web API for Docker is available at Docker Hub registry.

• To pull/download the Docker image, please type the following from a Terminal:

  AMD
  docker pull neodynamic/eplprinterwebapi:3.0.6
  ARM
  docker pull neodynamic/eplprinterwebapi:3.0.6-arm64

• To run the Docker image, please type the following from a Terminal:

  AMD
  docker run -it --rm -p 8080:8080 neodynamic/eplprinterwebapi:3.0.6
  ARM
  docker run -it --rm -p 8080:8080 neodynamic/eplprinterwebapi:3.0.6-arm64
   License Registration    Evaluation Mode Limitations    Change Log
  
  

  Special Parameters

  • Auto HTTPS Redirection: By default, HTTPS redirection is enabled. It can be disabled by specifying the following parameter -e "USE_HTTPS_REDIRECTION=false"
  • Swagger UI: By default, Swagger UI is enabled. It can be disabled by specifying the following parameter -e "SWAGGER_UI_ENABLED=false"

Run EPLPrinter WebAPI on a Custom Port

By default, our Docker image exposes port 8080 only. If you want to expose and use another different port, then do the following.

1. Let's suppose you want to use port 12345, then run the docker image with the following parameters:
   
   
   AMD

   docker run -it --rm -p 8080:12345 neodynamic/eplprinterwebapi:3.0.6 -e ASPNETCORE_HTTP_PORTS=12345

   ARM

   docker run -it --rm -p 8080:12345 neodynamic/eplprinterwebapi:3.0.6-arm64 -e ASPNETCORE_HTTP_PORTS=12345
2. Special case for port 80: If you need to use port 80, then run the docker image with the following parameters:
   
   
   AMD

   docker run -it --rm -p 8080:80 neodynamic/eplprinterwebapi:3.0.6 -u root -e ASPNETCORE_HTTP_PORTS=80

   ARM

   docker run -it --rm -p 8080:80 neodynamic/eplprinterwebapi:3.0.6-arm64 -u root -e ASPNETCORE_HTTP_PORTS=80

How To Use It - Basic Sample

The following source code invokes the EPLPrinter Web API for Docker to generate a PNG image for the specified EPL Commands. For more advanced settings please refer to the EPLPrintJob JSON Object

•   CURL
•   PHP
•   RUBY
•   PYTHON
•   PERL
•   JAVA
•   C#
•   JS/XHR
•   NODE

                    
curl -X POST "http://localhost:8080/EPLPrinter" \
     -H "Accept: image/png" \
     -H "Content-Type: application/json" \
     -d '{"eplCommands":"N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n"}' \
     --output label.png
                        
                

                    
$epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n";

$options = array(
  'http' => array(
    'method'  => 'POST',
    'content' => json_encode(array('eplCommands' => $epl)),
    'header'  => "Content-Type: application/json\r\n" .
                 "Accept: image/png\r\n"
  )
);

$response = file_get_contents('http://localhost:8080/EPLPrinter', false, stream_context_create($options));
file_put_contents('label.png', $response);
                        
                

                    
require 'net/http'
require 'uri'
require 'json'

uri = URI.parse("http://localhost:8080/EPLPrinter")
header = {'Accept' => 'image/png', 'Content-Type' => 'application/json'}

epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n"

http = Net::HTTP.new(uri.host, uri.port)
request = Net::HTTP::Post.new(uri.request_uri, header)
request.body = {eplCommands: epl}.to_json

response = http.request(request)
File.binwrite('label.png', response.body)
                        
                

                    
import requests

epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n"

response = requests.post(
    "http://localhost:8080/EPLPrinter",
    json={"eplCommands": epl},
    headers={"Accept": "image/png"}
)

if response.status_code == 200:
    with open("label.png", "wb") as f:
        f.write(response.content)
                        
                

                    
use LWP::UserAgent;
use JSON::PP;

my $epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n";

my $ua  = LWP::UserAgent->new;
my $req = HTTP::Request->new(POST => "http://localhost:8080/EPLPrinter");
$req->header('Content-Type' => 'application/json');
$req->header('Accept' => 'image/png');
$req->content(encode_json({ eplCommands => $epl }));

my $resp = $ua->request($req);
open(my $fh, '>:raw', 'label.png');
print $fh $resp->content;
close($fh);
                        
                

                    
// EPL escaped for JSON by hand (no extra dependencies): \r\n and \" stay escaped inside the JSON string
String json = "{\"eplCommands\":\"N\\r\\nq609\\r\\nQ203,26\\r\\nB26,26,0,UA0,2,2,152,B,\\\"603679025109\\\"\\r\\nA253,26,0,3,1,1,N,\\\"SKU 6205518 MFG 6354\\\"\\r\\nA253,56,0,3,1,1,N,\\\"2XIST TROPICAL BEACH\\\"\\r\\nA253,86,0,3,1,1,N,\\\"STRIPE SQUARE CUT TRUNK\\\"\\r\\nA253,116,0,3,1,1,N,\\\"BRICK\\\"\\r\\nA253,146,0,3,1,1,N,\\\"X-LARGE\\\"\\r\\nP1\\r\\n\"}";

CloseableHttpClient client = HttpClients.createDefault();
HttpPost httpPost = new HttpPost("http://localhost:8080/EPLPrinter");
httpPost.setEntity(new StringEntity(json, ContentType.APPLICATION_JSON));
httpPost.setHeader("Accept", "image/png");

CloseableHttpResponse response = client.execute(httpPost);
HttpEntity result = response.getEntity();
if (result != null) {
    try (FileOutputStream out = new FileOutputStream(new File("label.png"))) {
        result.writeTo(out);
    }
}
client.close();
                        
                

                    
using var http = new HttpClient();

string epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n";
string json = JsonSerializer.Serialize(new { eplCommands = epl });

var request = new HttpRequestMessage(HttpMethod.Post, "http://localhost:8080/EPLPrinter")
{
    Content = new StringContent(json, Encoding.UTF8, "application/json")
};
request.Headers.Accept.ParseAdd("image/png");

var response = await http.SendAsync(request);
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync("label.png", await response.Content.ReadAsByteArrayAsync());
                        
                

                    
// Browser (inside a <script type="module">): render the label in an img element
const epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n";

const response = await fetch("http://localhost:8080/EPLPrinter", {
    method: "POST",
    headers: { "Content-Type": "application/json", "Accept": "image/png" },
    body: JSON.stringify({ eplCommands: epl })
});
const blob = await response.blob();
document.getElementById("label").src = URL.createObjectURL(blob);
                        
                

                    
// Node.js 18+ (built-in fetch). Save as convert.mjs (ES module, top-level await)
import fs from "fs";
const epl = "N\r\nq609\r\nQ203,26\r\nB26,26,0,UA0,2,2,152,B,\"603679025109\"\r\nA253,26,0,3,1,1,N,\"SKU 6205518 MFG 6354\"\r\nA253,56,0,3,1,1,N,\"2XIST TROPICAL BEACH\"\r\nA253,86,0,3,1,1,N,\"STRIPE SQUARE CUT TRUNK\"\r\nA253,116,0,3,1,1,N,\"BRICK\"\r\nA253,146,0,3,1,1,N,\"X-LARGE\"\r\nP1\r\n";

const response = await fetch("http://localhost:8080/EPLPrinter", {
    method: "POST",
    headers: { "Content-Type": "application/json", "Accept": "image/png" },
    body: JSON.stringify({ eplCommands: epl })
});
fs.writeFileSync("label.png", Buffer.from(await response.arrayBuffer()));
                        
                

The Accept Header

The desired output rendering format must be specified through the Accept header. The supported formats are the following:

The EPLPrintJob Object

The EPLPrintJob is the JSON Object sent in the body of POST /EPLPrinter. It specifies the EPL commands (the only required property) and the printer settings like DPI, label size, colors, background and watermark images and output options.

{
  "eplCommands": "N\r\nq609\r\nQ203,26\r\nA253,26,0,3,1,1,N,\"SKU 6205518\"\r\nP1\r\n",
  "dpi": 203,
  "labelWidthInchUnit": 3,
  "labelHeightInchUnit": 1,
  "renderOutputRotation": 0,
  "enablePrinting": false
}

Errors

Successful requests return HTTP 200 with the output in the format requested by the Accept header. If an error occurs while processing the EPLPrintJob, the API returns HTTP 500 with a ProblemDetails JSON object:

{
  "type": "string",
  "title": "string",
  "status": 500,
  "detail": "string",
  "instance": "string"
}

If you get this error with valid EPL, please contact our support team.

Web API Doc

Interactive OpenAPI reference. The same swagger.json is used by the Swagger UI built into the container (enabled by default). All request properties are also listed in The EPLPrintJob Object.

EPL Commands Support

EPLPrinter Web API rendering engine supports most of the EPL formatting and control commands. The following table lists the supported commands. Not listed or unsupported commands will be skipped in the parsing stage.

Licensing

On-Premise - Full Deployment Control

EPLPrinter Web API is licensed for Private On-Premise environments giving you full control on the infrastructure where our product will run on. Please refer to Licensing model and prices...

 License Registration

When you buy a commercial license of EPLPrinter Web API for Docker, you are provided with license information (LicenseOwner & LicenseKey) to register the product. The license information must be specified to the Docker image as environment variables as follows:

Which EPL Edition Do I Need?

The same EPL rendering engine is available in four editions:

EPLPrinter Web API FAQ

How do I convert EPL to PDF with a REST API?

Run the container with docker run -p 8080:8080 neodynamic/eplprinterwebapi:3.0.6, then POST a JSON body like {"eplCommands":"N\nq609\n...P1\n"} to http://localhost:8080/EPLPrinter with the header Accept: application/pdf. The response is the PDF, with one page per label.

How do I convert EPL to ZPL to print on a ZPL-only Zebra printer?

Request Accept: application/vnd.zpl with enablePrinting set to true. The API returns the label as a ZPL graphic (GRF) formatted for printing, which you can send raw to the ZPL printer, for example to port 9100. Legacy applications that generate EPL keep working on newer ZPL printers without changing their label code. See the example.

Is it a self-hosted alternative to online EPL viewers?

Yes. EPLPrinter Web API runs as a Docker container on your own servers or cloud account, so labels with customer or shipping data never leave your infrastructure and there is no dependency on an external web service.

Which programming languages can I use?

Any language that can send an HTTP POST with JSON: Python, Node.js, JavaScript, Java, PHP, C#, Ruby, Perl, Go or curl. There is no SDK to install.

Which output formats are supported?

PNG, JPG, PDF and PCX, plus printer formats: Zebra GRF ASCII hex (ZPL), Zebra EPL binary graphic, Honeywell-Intermec FingerPrint, EPSON ESC/POS NV and HP PCL. The format is chosen with the Accept header.

How are multiple labels returned?

PDF returns all labels in one multipage file. For PNG, JPG, PCX and the printer formats, use the +json Accept variant to get a JSON array of Base64 data URIs, or the +zip variant to get a ZIP with one file per label. The plain variant returns only the first label.

Does it run on ARM64?

Yes. Images are published for amd64 (neodynamic/eplprinterwebapi:3.0.6) and arm64 (neodynamic/eplprinterwebapi:3.0.6-arm64).

Why does my rendered label look scaled or cut off?

The dpi value (152, 203, 300 or 600) must match the resolution the EPL was designed for, and the label size should match the q (label width) and Q (form length) commands. Use forceLabelWidth and forceLabelHeight to override q and Q.

What are the limitations of the evaluation version?

The trial is fully functional and does not expire, but it adds a TRIAL stamp to the output and replaces characters above byte value 127 with an X when resident fonts are used. See Evaluation Mode.

 Latest Release: v3.0.6 2026-01-26

• CRITICAL Fixed! Port 80 is no longer the default port. Changed to port 8080. This change now allows non-root users.
• Fixed! Updated all third-party libs and dependencies that are free of known vulnerabilities.

Full change log (all versions since v1.0) →