Uploading NICE CXone Digital API Viber Sticker Packs with Node.js

What You Will Build

• A Node.js module that constructs, validates, and uploads Viber sticker packs to the NICE CXone Digital messaging platform.
• The implementation uses the CXone Digital REST API with atomic POST operations, automatic CDN distribution triggers, and structured audit logging.
• The code is written in modern JavaScript with axios, sharp, and pino for production-grade reliability.

Prerequisites

• OAuth Client Type: Confidential client registered in CXone Admin Console
• Required Scopes: messaging:write, assets:write, messaging:read
• SDK/API Version: CXone Digital API v1 (REST)
• Runtime: Node.js 18 or higher
• Dependencies: npm install axios sharp pino uuid

Authentication Setup

CXone uses standard OAuth 2.0 Client Credentials flow. Tokens expire after one hour and require caching to avoid unnecessary authentication requests. The following client handles token acquisition, caching, and automatic refresh when the Authorization header returns a 401 response.

const axios = require('axios');
const pino = require('pino');

const logger = pino({ level: 'info' });

class CXoneAuthClient {
  constructor(region, clientId, clientSecret) {
    this.region = region;
    this.clientId = clientId;
    this.clientSecret = clientSecret;
    this.tokenUrl = `https://${region}.platform.nicecxone.com/oauth/token`;
    this.accessToken = null;
    this.tokenExpiry = 0;
  }

  async getAccessToken() {
    if (this.accessToken && Date.now() < this.tokenExpiry - 60000) {
      return this.accessToken;
    }

    const auth = Buffer.from(`${this.clientId}:${this.clientSecret}`).toString('base64');
    
    const response = await axios.post(this.tokenUrl, {
      grant_type: 'client_credentials',
      scope: 'messaging:write assets:write messaging:read'
    }, {
      headers: {
        Authorization: `Basic ${auth}`,
        'Content-Type': 'application/x-www-form-urlencoded'
      }
    });

    this.accessToken = response.data.access_token;
    this.tokenExpiry = Date.now() + (response.data.expires_in * 1000);
    return this.accessToken;
  }

  getAuthHeaders() {
    return async () => {
      const token = await this.getAccessToken();
      return {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
        Accept: 'application/json'
      };
    };
  }
}

Implementation

Step 1: Initialize API Client with Retry and Latency Tracking

The base HTTP client must handle rate limiting (429), track request latency, and attach audit metadata. CXone enforces strict rate limits on asset ingestion endpoints. The client implements exponential backoff and records success/failure rates for governance reporting.

class CXoneDigitalClient {
  constructor(authClient, baseUrl) {
    this.auth = authClient;
    this.baseUrl = baseUrl;
    this.auditLog = [];
    this.metrics = {
      totalUploads: 0,
      successfulCommits: 0,
      averageLatencyMs: 0
    };
  }

  async request(method, path, data = null, auditContext = {}) {
    const startTime = Date.now();
    this.metrics.totalUploads++;
    
    const headers = await this.auth.getAuthHeaders();
    const url = `${this.baseUrl}${path}`;

    try {
      const response = await axios({
        method,
        url,
        headers,
        data,
        timeout: 30000
      });

      const latency = Date.now() - startTime;
      this.metrics.successfulCommits++;
      this.metrics.averageLatencyMs = 
        ((this.metrics.averageLatencyMs * (this.metrics.totalUploads - 1)) + latency) / this.metrics.totalUploads;

      this.auditLog.push({
        timestamp: new Date().toISOString(),
        method,
        path,
        status: response.status,
        latencyMs: latency,
        context: auditContext,
        success: true
      });

      return response.data;
    } catch (error) {
      const latency = Date.now() - startTime;
      const isRetryable = error.response?.status === 429 || 
                          (error.response?.status >= 500 && error.response?.status < 599);
      
      if (isRetryable) {
        const retryDelay = Math.min(1000 * Math.pow(2, error.response?.headers?.['retry-after'] || 0), 5000);
        logger.warn(`Rate limited or server error on ${path}. Retrying in ${retryDelay}ms`);
        await new Promise(resolve => setTimeout(resolve, retryDelay));
        return this.request(method, path, data, auditContext);
      }

      this.auditLog.push({
        timestamp: new Date().toISOString(),
        method,
        path,
        status: error.response?.status || 500,
        latencyMs: latency,
        context: auditContext,
        success: false,
        error: error.message
      });

      throw error;
    }
  }
}

Step 2: Construct and Validate Upload Payloads

Viber sticker packs require strict schema compliance. Each sticker must be PNG or JPEG, under 512KB, and exactly 512x512 pixels. The pack requires a UUID reference, an ordered asset matrix, and a content rating directive (0 to 3). The validation pipeline checks format, size, dimensions, and metadata completeness before any network call occurs.

const sharp = require('sharp');
const { v4: uuidv4 } = require('uuid');
const fs = require('fs').promises;
const path = require('path');

const VIBER_CONSTRAINTS = {
  MAX_FILE_SIZE_BYTES: 512 * 1024,
  REQUIRED_DIMENSIONS: 512,
  ALLOWED_MIME_TYPES: ['image/png', 'image/jpeg'],
  VALID_CONTENT_RATINGS: [0, 1, 2, 3]
};

async function validateStickerAsset(filePath) {
  const stats = await fs.stat(filePath);
  if (stats.size > VIBER_CONSTRAINTS.MAX_FILE_SIZE_BYTES) {
    throw new Error(`Asset ${path.basename(filePath)} exceeds 512KB limit`);
  }

  const metadata = await sharp(filePath).metadata();
  if (!VIBER_CONSTRAINTS.ALLOWED_MIME_TYPES.includes(metadata.format)) {
    throw new Error(`Asset ${path.basename(filePath)} must be PNG or JPEG`);
  }

  if (metadata.width !== VIBER_CONSTRAINTS.REQUIRED_DIMENSIONS || 
      metadata.height !== VIBER_CONSTRAINTS.REQUIRED_DIMENSIONS) {
    throw new Error(`Asset ${path.basename(filePath)} must be exactly 512x512 pixels`);
  }

  const buffer = await fs.readFile(filePath);
  return {
    fileName: path.basename(filePath),
    base64: buffer.toString('base64'),
    mimeType: `image/${metadata.format}`,
    sizeBytes: stats.size,
    validated: true
  };
}

function validatePackPayload(payload) {
  if (!payload.packId || !/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(payload.packId)) {
    throw new Error('Invalid pack UUID format');
  }
  if (!Array.isArray(payload.assets) || payload.assets.length < 1 || payload.assets.length > 50) {
    throw new Error('Pack must contain between 1 and 50 sticker assets');
  }
  if (!VIBER_CONSTRAINTS.VALID_CONTENT_RATINGS.includes(payload.contentRating)) {
    throw new Error('Content rating must be between 0 and 3');
  }
  if (!payload.name || payload.name.length < 1 || payload.name.length > 100) {
    throw new Error('Pack name is required and must be between 1 and 100 characters');
  }
  return true;
}

Step 3: Atomic Asset Ingestion and CDN Distribution Trigger

CXone processes sticker packs through an atomic POST operation. The endpoint accepts the validated payload and automatically triggers CDN distribution for safe upload iteration. The client exposes callback handlers to synchronize with external asset libraries and records commit success rates.

class ViberStickerPackUploader {
  constructor(authClient, region) {
    this.client = new CXoneDigitalClient(authClient, `https://${region}.platform.nicecxone.com/api/v1/messaging/channels/viber`);
    this.callbacks = {
      onAssetValidated: null,
      onPackCommitted: null,
      onCdnDistributionTriggered: null,
      onError: null
    };
  }

  on(event, handler) {
    if (this.callbacks.hasOwnProperty(event)) {
      this.callbacks[event] = handler;
    }
  }

  async uploadPack(packName, assetPaths, contentRating, externalLibraryId = null) {
    const packId = uuidv4();
    const uploadStart = Date.now();
    
    logger.info(`Starting sticker pack upload: ${packName} (${assetPaths.length} assets)`);

    const validatedAssets = [];
    for (const assetPath of assetPaths) {
      try {
        const asset = await validateStickerAsset(assetPath);
        validatedAssets.push(asset);
        if (this.callbacks.onAssetValidated) {
          this.callbacks.onAssetValidated(asset.fileName, asset.sizeBytes);
        }
      } catch (error) {
        logger.error(`Asset validation failed: ${error.message}`);
        throw error;
      }
    }

    const payload = {
      packId,
      name: packName,
      contentRating,
      assets: validatedAssets.map((a, index) => ({
        sequence: index + 1,
        fileName: a.fileName,
        mimeType: a.mimeType,
        base64Data: a.base64,
        sizeBytes: a.sizeBytes
      })),
      metadata: {
        uploadedAt: new Date().toISOString(),
        externalLibraryId,
        platform: 'viber',
        version: '1.0'
      }
    };

    validatePackPayload(payload);

    try {
      const response = await this.client.request('POST', '/sticker-packs', payload, {
        packId,
        packName,
        assetCount: assetPaths.length,
        externalLibraryId
      });

      const uploadLatency = Date.now() - uploadStart;
      
      logger.info(`Pack committed successfully: ${packId} in ${uploadLatency}ms`);
      
      if (this.callbacks.onPackCommitted) {
        this.callbacks.onPackCommitted(packId, response, uploadLatency);
      }

      if (this.callbacks.onCdnDistributionTriggered) {
        this.callbacks.onCdnDistributionTriggered(packId, response.cdnUrls || []);
      }

      return {
        success: true,
        packId,
        latencyMs: uploadLatency,
        cdnUrls: response.cdnUrls || [],
        auditSnapshot: this.client.auditLog.slice(-3)
      };

    } catch (error) {
      logger.error(`Pack upload failed: ${error.response?.data?.message || error.message}`);
      if (this.callbacks.onError) {
        this.callbacks.onError(packId, error);
      }
      throw error;
    }
  }

  getMetrics() {
    return {
      ...this.client.metrics,
      auditLogCount: this.client.auditLog.length,
      lastAuditEntries: this.client.auditLog.slice(-5)
    };
  }
}

Complete Working Example

The following script demonstrates a complete, runnable implementation. It initializes authentication, configures callbacks, validates local assets, and uploads the pack to CXone Digital. Replace environment variables with your CXone tenant credentials.

require('dotenv').config();
const CXoneAuthClient = require('./cxone-auth');
const ViberStickerPackUploader = require('./viber-uploader');

async function main() {
  const REGION = process.env.CXONE_REGION || 'usw2';
  const CLIENT_ID = process.env.CXONE_CLIENT_ID;
  const CLIENT_SECRET = process.env.CXONE_CLIENT_SECRET;
  const ASSET_DIR = process.env.ASSET_DIRECTORY || './sticker-assets';

  if (!CLIENT_ID || !CLIENT_SECRET) {
    throw new Error('CXONE_CLIENT_ID and CXONE_CLIENT_SECRET must be set');
  }

  const auth = new CXoneAuthClient(REGION, CLIENT_ID, CLIENT_SECRET);
  const uploader = new ViberStickerPackUploader(auth, REGION);

  uploader.on('onAssetValidated', (fileName, size) => {
    console.log(`[VALIDATION] ${fileName} passed format and size checks (${size} bytes)`);
  });

  uploader.on('onPackCommitted', (packId, response, latency) => {
    console.log(`[COMMIT] Pack ${packId} committed in ${latency}ms`);
    console.log(`[COMMIT] CXone response:`, JSON.stringify(response, null, 2));
  });

  uploader.on('onCdnDistributionTriggered', (packId, urls) => {
    console.log(`[CDN] Distribution triggered for ${packId}`);
    urls.forEach(url => console.log(`  -> ${url}`));
  });

  uploader.on('onError', (packId, error) => {
    console.error(`[ERROR] Upload failed for ${packId}:`, error.message);
  });

  try {
    const fs = require('fs').promises;
    const assetFiles = await fs.readdir(ASSET_DIR);
    const assetPaths = assetFiles
      .filter(f => /\.(png|jpg|jpeg)$/i.test(f))
      .map(f => `${ASSET_DIR}/${f}`);

    if (assetPaths.length === 0) {
      throw new Error('No valid image assets found in directory');
    }

    console.log(`Uploading ${assetPaths.length} assets as pack "Holiday Stickers"`);
    const result = await uploader.uploadPack(
      'Holiday Stickers',
      assetPaths,
      1,
      'lib-ext-998877'
    );

    console.log('Upload complete.');
    console.log('Metrics:', JSON.stringify(uploader.getMetrics(), null, 2));

  } catch (error) {
    console.error('Fatal execution error:', error.message);
    process.exit(1);
  }
}

main();

Common Errors & Debugging

Error: 400 Bad Request - Schema Validation Failure

• Cause: The payload violates Viber platform constraints. Common triggers include incorrect image dimensions, missing contentRating, or packId format mismatch.
• Fix: Verify all assets pass the validateStickerAsset function. Ensure the packId matches RFC 4122 UUID format. Check that contentRating is an integer between 0 and 3.
• Code Fix: Add explicit logging before the POST call to print payload structure and compare against the CXone API schema.

Error: 401 Unauthorized - Token Expired or Invalid

• Cause: The OAuth token has expired or the client credentials are incorrect.
• Fix: The CXoneAuthClient caches tokens and refreshes automatically. If this error persists, verify CXONE_CLIENT_ID and CXONE_CLIENT_SECRET match your CXone Admin Console registration. Ensure the client has messaging:write and assets:write scopes assigned.

Error: 403 Forbidden - Insufficient Scope

• Cause: The registered OAuth client lacks the required API permissions.
• Fix: Navigate to CXone Admin Console > Integration > OAuth Clients > Edit > Scopes. Add messaging:write and assets:write. Regenerate the client secret if scope changes require token rotation.

Error: 413 Payload Too Large - Asset Size Exceeded

• Cause: Individual sticker files exceed the 512KB Viber limit, or the total JSON payload exceeds CXone request size thresholds.
• Fix: The validation pipeline enforces VIBER_CONSTRAINTS.MAX_FILE_SIZE_BYTES. If this error occurs, compress images before upload or split the pack into smaller batches. CXone accepts up to 50 assets per atomic POST.

Error: 429 Too Many Requests - Rate Limit Cascade

• Cause: Excessive concurrent upload requests trigger CXone rate limiting.
• Fix: The CXoneDigitalClient implements exponential backoff with retry-after header parsing. For high-volume pipelines, implement a queue with a maximum concurrency of 3 requests per second per tenant.

Error: 500 Internal Server Error - CDN Ingestion Failure

• Cause: Temporary failure in CXone asset ingestion or CDN distribution service.
• Fix: The retry logic handles transient 5xx errors. If failures persist beyond three retries, check CXone status pages or contact support with the packId and audit log timestamps.

Official References

• CXone Digital Messaging API Documentation
• CXone OAuth 2.0 Client Credentials Flow
• Viber Sticker Platform Specifications
• CXone Asset Management Endpoints