Steganography Online Codec Web API SDK Documentation

Automate hiding secret data in images & photos using Steganography Online Codec Web API SDKs.

Description

You can use all of the features of Steganography Online Codec via our Web API interface. The Web API is based on POST requests and emits JSON encoded responses.

Installation

For fast deployment you can install Steganography Online Codec SDKs via popular programming library repositories. The source code has also been published on Github:

Repository Language Installation Package Sources
PyPI Repository for Python Python pip install steganography-online-codec PyPI GitHub
JavaScript programming language JavaScript

Run

npm i steganography-online-codec

or add the following to dependencies section of your package.json file

"dependencies": {
  "steganography-online-codec": "latest"
},

 npm GitHub

Usage examples

Hide an encrypted message in an image file

#!/usr/bin/env python

###############################################################################
#
# Steganography Online Codec WebApi interface usage example.
#
# This example shows how to hide an encrypted secret message in an image file.
#
# Version      : v1.00
# Language     : Python
# Author       : Bartosz Wójcik
# Project      : https://www.pelock.com/products/steganography-online-codec
# Homepage     : https://www.pelock.com
#
###############################################################################

#
# include Steganography Online Codec module
#
from steganography_online_codec import *

#
# create Steganography Online Codec class instance (we are using our activation key)
#
mySteganographyOnlineCodec = SteganographyOnlineCodec("YOUR-WEB-API-KEY")

#
# encode a hidden message (encrypted with your password) within an image file
#
result = mySteganographyOnlineCodec.encode("input_file.jpg", "Secret message", "Pa$$word", "output_file_with_hidden_secret_message.png")

#
# result[] array holds the encoding results as well as other information
#
if result and "error" in result:
    if result["error"] == Errors.SUCCESS:
        print(f'Secret messaged encoded and saved to the output PNG file.')
    else:
        print(f'Error code {result["error"]}')
else:
    print("Something unexpected happen while trying to encode the message.")
"use strict";

/******************************************************************************
 *
 * Steganography Online Codec WebApi interface usage example.
 *
 * In this example shows how to hide an encrypted secret message in an image file.
 *
 * Version      : v1.00
 * Language     : JavaScript
 * Author       : Bartosz Wójcik (original example)
 * Project      : https://www.pelock.com/products/steganography-online-codec
 * Homepage     : https://www.pelock.com
 *
 * @link https://www.pelock.com/products/steganography-online-codec
 * @copyright Copyright (c) 2020-2025 PELock LLC
 * @license Apache-2.0
 *
/*****************************************************************************/

// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';

// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');

// encode a hidden message (encrypted with your password) within an image file
(async () => {

	const inputFile = 'input_file.jpg';
	const secretMessage = 'Secret message';
	const password = 'Pa$$word';
	const outputFile = 'output_file_with_hidden_secret_message.png';

	try {
		const result = await mySteganographyOnlineCodec.encode(inputFile, secretMessage, password, outputFile);

		// result object holds the encoding results as well as other information
		console.log('Secret messaged encoded and saved to the output PNG file.');
	} catch (err) {
		console.error('Encoding failed:', err.error_message || err.message || String(err));
	}
})();

Extract hidden message from the encoded image

#!/usr/bin/env python

###############################################################################
#
# Steganography Online Codec WebApi interface usage example.
#
# In this example, we will see how to extract a previously encrypted & hidden
# secret message from an image file.
#
# Version      : v1.00
# Language     : Python
# Author       : Bartosz Wójcik
# Project      : https://www.pelock.com/products/steganography-online-codec
# Homepage     : https://www.pelock.com
#
###############################################################################

#
# include Steganography Online Codec module
#
from steganography_online_codec import *

#
# if you don't want to use Python module, you can import directly from the file
#
#from pelock.steganography_online_codec import *


#
# create Steganography Online Codec class instance (we are using our activation key)
#
mySteganographyOnlineCodec = SteganographyOnlineCodec("YOUR-WEB-API-KEY")

#
# extract a hidden message from the previously encoded image file
#

# full version image size limit is set to 10 MB (demo 50 kB max)
# supported image format is PNG and only PNG!
input_file_path = "output_file_with_hidden_secret_message.png"

# full version password length is 128 characters max (demo 8 chars max)
password = "Pa$$word"

# extract a hidden message from the image (PNG files only)
result = mySteganographyOnlineCodec.decode(input_file_path, password)

#
# result[] Dict holds the decoding results as well as other information
#
if result and "error" in result:

    print(f'You are running in {"full" if result["license"]["activationStatus"] is True else "demo"} version')

    if result["error"] == Errors.SUCCESS:
        print(f'Secret message is "{result["message"]}"')
        print(f'Remaining number of usage credits - {result["license"]["usagesCount"]}')
    elif result["error"] == Errors.INVALID_INPUT:
        print(f'Invalid input file {input_file_path} or file doesn''t exist')
    elif result["error"] == Errors.IMAGE_TOO_BIG:
        print(f'Image file is too big, current limit is set to {mySteganographyOnlineCodec.convert_size(result["limits"]["maxFileSize"])}')
    elif result["error"] == Errors.LIMIT_MESSAGE:
        print(f'Extracted message is too long, current limit is set to {result["limits"]["maxMessageLen"]}')
    elif result["error"] == Errors.LIMIT_PASSWORD:
        print(f'Password is too long, current limit is set to {result["limits"]["maxPasswordLen"]}')
    elif result["error"] == Errors.INVALID_PASSWORD:
        print(f'Invalid password')
    else:
        print(f'An unknown error occurred, error code: {result["error"]}')
else:
    print("Something unexpected happen while trying to extract the secret message.")
"use strict";

/******************************************************************************
 *
 * Steganography Online Codec WebApi interface usage example.
 *
 * In this example, we will see how to extract a previously encrypted & hidden
 * secret message from an image file.
 *
 * Version      : v1.00
 * Language     : JavaScript
 * Author       : Bartosz Wójcik
 * Project      : https://www.pelock.com/products/steganography-online-codec
 * Homepage     : https://www.pelock.com
 *
 * @link https://www.pelock.com/products/steganography-online-codec
 * @copyright Copyright (c) 2020-2025 PELock LLC
 * @license Apache-2.0
 *
 /*****************************************************************************/

// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';

// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');

// extract a hidden message from the previously encoded image file
(async () => {
	// full version image size limit is set to 10 MB (demo 50 kB max)
	// supported image format is PNG and only PNG!
	const inputFilePath = 'output_file_with_hidden_secret_message.png';

	// full version password length is 128 characters max (demo 8 chars max)
	const password = 'Pa$$word';

	try {
		// extract a hidden message from the image (PNG files only)
		const result = await mySteganographyOnlineCodec.decode(inputFilePath, password);

		// result object holds the decoding results as well as other information
		console.log(`You are running in ${result.license?.activationStatus ? 'full' : 'demo'} version`);

		console.log(`Secret message is "${result.message}"`);

		if (result.license && result.license.usagesCount !== undefined) {
			console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
		}
	} catch (err) {
		switch (err.error) {
			case Errors.INVALID_INPUT:
				console.log(`Invalid input file ${inputFilePath} or file doesn't exist`);
				break;
			case Errors.IMAGE_TOO_BIG:
				console.log(`Image file is too big, current limit is set to ${err.raw?.limits?.maxFileSize ?? 'unknown'}`);
				break;
			case Errors.LIMIT_MESSAGE:
				console.log(`Extracted message is too long, current limit is set to ${err.raw?.limits?.maxMessageLen ?? 'unknown'}`);
				break;
			case Errors.LIMIT_PASSWORD:
				console.log(`Password is too long, current limit is set to ${err.raw?.limits?.maxPasswordLen ?? 'unknown'}`);
				break;
			case Errors.INVALID_PASSWORD:
				console.log('Invalid password');
				break;
			default:
				console.log(`An error occurred: ${err.error_message ?? String(err)}`);
		}
	}
})();

Hide secret message in photo (extended error handling)

#!/usr/bin/env python

###############################################################################
#
# Steganography Online Codec WebApi interface usage example.
#
# In this example, we will see how to hide an encrypted message in an
# image file using our codec.
#
# Version      : v1.00
# Language     : Python
# Author       : Bartosz Wójcik
# Project      : https://www.pelock.com/products/steganography-online-codec
# Homepage     : https://www.pelock.com
#
###############################################################################

#
# include Steganography Online Codec module
#
from steganography_online_codec import *

#
# if you don't want to use Python module, you can import directly from the file
#
#from pelock.steganography_online_codec import *

#
# create Steganography Online Codec class instance (we are using our activation key)
#
mySteganographyOnlineCodec = SteganographyOnlineCodec("YOUR-WEB-API-KEY")

#
# encode a hidden message within the source image file
#

# full version image size limit is set to 10 MB (demo 50 kB max)
# supported image formats are PNG, JPG, GIF, BMP, WBMP, GD2, AVIF, WEBP (mail me for more)
input_file_path = "input_file.webp"

# full version message size is unlimited (demo 16 chars max)
secret_message = "Secret message"

# full version password length is 128 characters max (demo 8 chars max)
password = "Pa$$word"

# where to save encoded image with the secret message
output_file_path = "output_file_with_hidden_secret_message.png"

# encode a hidden message (encrypted with your password) within an image file
result = mySteganographyOnlineCodec.encode(input_file_path, secret_message, password, output_file_path)

#
# result[] array holds the encoding results as well as other information
#
if result and "error" in result:

    print(f'You are running in {"full" if result["license"]["activationStatus"] is True else "demo"} version')

    if result["error"] == Errors.SUCCESS:
        print(f'Secret messaged encoded and saved to {output_file_path}')
        print(f'Remaining number of usage credits - {result["license"]["usagesCount"]}')
    elif result["error"] == Errors.INVALID_INPUT:
        print(f'Invalid input file {input_file_path} or file doesn''t exist')
    elif result["error"] == Errors.MESSAGE_TOO_LONG:
        print(f'Message is too long for the provided image file, use larger file')
    elif result["error"] == Errors.IMAGE_TOO_BIG:
        print(f'Image file is too big, current limit is set to {mySteganographyOnlineCodec.convert_size(result["limits"]["maxFileSize"])}')
    elif result["error"] == Errors.LIMIT_MESSAGE:
        print(f'Message is too long, current limit is set to {result["limits"]["maxMessageLen"]}')
    elif result["error"] == Errors.LIMIT_PASSWORD:
        print(f'Password is too long, current limit is set to {result["limits"]["maxPasswordLen"]}')
    elif result["error"] == Errors.INVALID_PASSWORD:
        print(f'Invalid password')
    else:
        print(f'An unknown error occurred, error code: {result["error"]}')
else:
    print("Something unexpected happen while trying to encode the message.")
"use strict";

/******************************************************************************
 *
 * Steganography Online Codec WebApi interface usage example.
 *
 * In this example, we will see how to hide an encrypted message in an
 * image file using our codec.
 *
 * Version      : v1.00
 * Language     : JavaScript
 * Author       : Bartosz Wójcik
 * Project      : https://www.pelock.com/products/steganography-online-codec
 * Homepage     : https://www.pelock.com
 *
 * @link https://www.pelock.com/products/steganography-online-codec
 * @copyright Copyright (c) 2020-2025 PELock LLC
 * @license Apache-2.0
 *
 /*****************************************************************************/

// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';


// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');

// encode a hidden message within the source image file
(async () => {
	// full version image size limit is set to 10 MB (demo 50 kB max)
	// supported image formats are PNG, JPG, GIF, BMP, WBMP, GD2, AVIF, WEBP (mail me for more)
	const inputFilePath = 'input_file.webp';

	// full version message size is unlimited (demo 16 chars max)
	const secretMessage = 'Secret message';

	// full version password length is 128 characters max (demo 8 chars max)
	const password = 'Pa$$word';

	// where to save encoded image with the secret message
	const outputFilePath = 'output_file_with_hidden_secret_message.png';

	try {
		// encode a hidden message (encrypted with your password) within an image file
		const result = await mySteganographyOnlineCodec.encode(inputFilePath, secretMessage, password, outputFilePath);

		// result object holds the encoding results as well as other information
		const versionType = result.license && result.license.activationStatus ? 'full' : 'demo';
		console.log(`You are running in ${versionType} version`);

		console.log(`Secret messaged encoded and saved to ${outputFilePath}`);
		if (result.license && result.license.usagesCount !== undefined) {
			console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
		}
	} catch (err) {
		const errorCode = err.error;

		switch (errorCode) {
			case Errors.INVALID_INPUT:
				console.log(`Invalid input file ${inputFilePath} or file doesn't exist`);
				break;
			case Errors.MESSAGE_TOO_LONG:
				console.log('Message is too long for the provided image file, use larger file');
				break;
			case Errors.IMAGE_TOO_BIG:
				console.log(`Image file is too big, current limit is set to ${err.raw?.limits?.maxFileSize ?? 'unknown'}`);
				break;
			case Errors.LIMIT_MESSAGE:
				console.log(`Message is too long, current limit is set to ${err.raw?.limits?.maxMessageLen ?? 'unknown'}`);
				break;
			case Errors.LIMIT_PASSWORD:
				console.log(`Password is too long, current limit is set to ${err.raw?.limits?.maxPasswordLen ?? 'unknown'}`);
				break;
			case Errors.INVALID_PASSWORD:
				console.log('Invalid password');
				break;
			default:
				console.log(`An error occurred: ${err.error_message ?? `Error code ${errorCode}`}`);
		}
	}
})();

Check license information

#!/usr/bin/env python

###############################################################################
#
# Steganography Online Codec WebApi interface usage example.
#
# In this example we will verify our activation key status.
#
# Version      : v1.00
# Language     : Python
# Author       : Bartosz Wójcik
# Project      : https://www.pelock.com/products/steganography-online-codec
# Homepage     : https://www.pelock.com
#
###############################################################################

#
# include Steganography Online Codec module
#
from steganography_online_codec import *

#
# if you don't want to use Python module, you can import directly from the file
#
#from pelock.steganography_online_codec import *

#
# create Steganography Online Codec class instance (we are using our activation key)
#
mySteganographyOnlineCodec = SteganographyOnlineCodec("YOUR-WEB-API-KEY")

#
# login to the service
#
result = mySteganographyOnlineCodec.login()

#
# result[] Dict holds the information about the license & current limits
#
if result:

    print(f'You are running in {"full" if result["license"]["activationStatus"] is True else "demo"} version')

    # information about the current license
    if result["license"]["activationStatus"] is True:
        print(f'Registered for - {result["license"]["userName"]}')
        print(f'License type - {"personal" if result["license"]["type"] == 0 else "company"}')
        print(f'Total number of purchased usage credits - {result["license"]["usagesTotal"]}')
        print(f'Remaining number of usage credits - {result["license"]["usagesCount"]}')

    # current limits (different for DEMO and FULL versions)
    print(f'Max. password length - {result["limits"]["maxPasswordLen"]}')
    print(f'Max. message length - {"unlimited" if result["limits"]["maxMessageLen"] == -1 else result["limits"]["maxMessageLen"]}')
    print(f'Max. input image file size - {mySteganographyOnlineCodec.convert_size(result["limits"]["maxFileSize"])}')
else:
    print("Something unexpected happen while trying to login to the service.")
"use strict";

/******************************************************************************
 *
 * Steganography Online Codec WebApi interface usage example.
 *
 * In this example we will verify our activation key status.
 *
 * Version      : v1.00
 * Language     : JavaScript
 * Author       : Bartosz Wójcik
 * Project      : https://www.pelock.com/products/steganography-online-codec
 * Homepage     : https://www.pelock.com
 *
 * @link https://www.pelock.com/products/steganography-online-codec
 * @copyright Copyright (c) 2020-2025 PELock LLC
 * @license Apache-2.0
 *
 /*****************************************************************************/

// include Steganography Online Codec module
import { SteganographyOnlineCodec, Errors } from 'steganography-online-codec';
// or if tested locally use:
//import { SteganographyOnlineCodec, Errors } from '../src/SteganographyOnlineCodec.mjs';

// create Steganography Online Codec class instance (we are using our activation key)
const mySteganographyOnlineCodec = new SteganographyOnlineCodec('YOUR-WEB-API-KEY');

// login to the service
(async () => {
	try {
		const result = await mySteganographyOnlineCodec.login();

		// result object holds the information about the license & current limits
		const versionType = result.license && result.license.activationStatus ? 'full' : 'demo';
		console.log(`You are running in ${versionType} version`);

		// information about the current license
		if (result.license && result.license.activationStatus) {
			console.log(`Registered for - ${result.license.userName}`);
			const licenseType = result.license.type === 0 ? 'personal' : 'company';
			console.log(`License type - ${licenseType}`);
			console.log(`Total number of purchased usage credits - ${result.license.usagesTotal}`);
			console.log(`Remaining number of usage credits - ${result.license.usagesCount}`);
		}

		// current limits (different for DEMO and FULL versions)
		if (result.limits) {
			console.log(`Max. password length - ${result.limits.maxPasswordLen}`);
			const msgLen = result.limits.maxMessageLen === -1 ? 'unlimited' : result.limits.maxMessageLen;
			console.log(`Max. message length - ${msgLen}`);
			console.log(`Max. input image file size - ${mySteganographyOnlineCodec.convert_size(result.limits.maxFileSize)}`);
		}
	} catch (err) {
		console.error(`Login failed: ${err.error_message || String(err)}`);
	}
})();

Return values

result["error"] [out]
Error code. One of the following:
Name Value Description
WEBAPI_CONNECTION -1 Cannot connect to the Web API interface (network error, returned only by the SDK).
SUCCESS 0 Everything went fine.
UNKNOWN 1 Unknown error.
MESSAGE_TOO_LONG 2 Message is too long for the selected image file (use larger image file).
IMAGE_TOO_BIG 3 Image file is too big (10 MB for full version, 50 kB for DEMO mode).
INVALID_INPUT 4 Image file is invalid.
INVALID_IMAGE_FORMAT 5 Image file format is not supported.
IMAGE_MALFORMED 6 Image file is malformed and cannot write or read the encoded message.
INVALID_PASSWORD 7 Provided password is invalid (max. length 128 chars for full version, 8 for DEMO mode).
LIMIT_MESSAGE 9 Provided message is too long (unlimited size for the full version, 16 for DEMO mode).
LIMIT_PASSWORD 10 Provided password is invalid (max. length 128 chars for full version, 8 for DEMO mode).
OUTPUT_FILE 99 Error while writing output file (returned only by the SDK library).
INVALID_LICENSE 100 License key is invalid or expired.
result["message"] [out, optional]
Decoded secret message.
result["limits"]["maxFileSize"] [out, optional]
Max. allowed file size.
result["limits"]["maxMessageLen"] [out, optional]
Max. allowed secret message length (default -1 for unlimited length that will fit the input file size).
result["limits"]["maxPasswordLen"] [out, optional]
Max. allowed password length.
result["license"]["activationStatus"] [out, optional]
Activation status - true for full version false for demo version.
result["license"]["userName"] [out, optional]
Registered user name.
result["license"]["type"] [out, optional]
License type - 0 for Personal License, 1 for Company License.
result["license"]["usagesTotal"] [out, optional]
Total number of purchased usage credits.
result["license"]["usagesCount"] [out]
Remaining number of usage credits (always returned for encoding/decodings, for demo version it's always set to 1).

Requirements

Python 3 Module steganography-online-codec
JavaScript NPM Module steganography-online-codec

Questions?

If you would like to ask me about Steganography Online Codec SDKs, or something's not clear, mail me. I'll be happy to answer all of your questions.