Reconciling NICE Cognigy Webhooks Outbound Queues with TypeScript

What You Will Build

• The code builds a TypeScript queue reconciler that fetches pending outbound webhook notifications, validates them against dialog engine constraints, and dispatches them with configurable retry and backoff logic.
• It uses the NICE Cognigy REST API endpoints /api/v1/webhooks/queues/pending and /api/v1/webhooks/reconcile.
• The tutorial covers TypeScript with Node.js runtime, axios, crypto, zod, and winston for production-grade delivery assurance.

Prerequisites

• OAuth client type: Cognigy Service Account (JWT or API Key)
• Required scopes: webhook:read, webhook:write, queue:manage
• SDK/API version: Cognigy API v1
• Language/runtime: Node.js 18+, TypeScript 5+
• Dependencies: npm install axios crypto uuid winston zod

Authentication Setup

Cognigy uses a standard JWT authentication flow. You must exchange service account credentials for a bearer token before issuing queue operations. The token expires after twenty-four hours and requires caching to prevent unnecessary authentication overhead.

import axios, { AxiosInstance } from 'axios';
import { createHash, timingSafeEqual } from 'crypto';

interface CognigyAuthConfig {
  tenantHost: string;
  username: string;
  password: string;
}

let cachedToken: string | null = null;
let tokenExpiry: number = 0;

export async function getCognigyClient(config: CognigyAuthConfig): Promise<AxiosInstance> {
  const now = Date.now();
  if (cachedToken && now < tokenExpiry) {
    return createAuthenticatedClient(config.tenantHost, cachedToken);
  }

  const loginUrl = `https://${config.tenantHost}/api/v1/auth/login`;
  const response = await axios.post(loginUrl, {
    username: config.username,
    password: config.password
  });

  cachedToken = response.data.token;
  tokenExpiry = now + (response.data.expiresIn * 1000);

  return createAuthenticatedClient(config.tenantHost, cachedToken);
}

function createAuthenticatedClient(host: string, token: string): AxiosInstance {
  const client = axios.create({
    baseURL: `https://${host}`,
    headers: {
      Authorization: `Bearer ${token}`,
      'Content-Type': 'application/json',
      'X-Api-Version': 'v1'
    }
  });

  client.interceptors.response.use(
    (res) => res,
    (err) => {
      if (err.response?.status === 401) {
        cachedToken = null;
        tokenExpiry = 0;
      }
      return Promise.reject(err);
    }
  );

  return client;
}

Implementation

Step 1: Initialize Client and Fetch Pending Queue

The reconciler begins by querying the pending webhook queue. Cognigy returns paginated results using a cursor-based mechanism. You must handle pagination to ensure complete queue processing and enforce maximum queue depth limits to prevent memory exhaustion during high-volume dialog scaling.

import { z } from 'zod';

interface QueueItem {
  id: string;
  webhookUrl: string;
  payload: Record<string, unknown>;
  createdAt: string;
  retryCount: number;
  lastStatus: number | null;
}

const QueueItemSchema = z.object({
  id: z.string().uuid(),
  webhookUrl: z.string().url(),
  payload: z.record(z.unknown()),
  createdAt: z.string().datetime(),
  retryCount: z.number().int().min(0),
  lastStatus: z.number().int().nullable()
});

export async function fetchPendingQueue(client: AxiosInstance, maxDepth: number = 500): Promise<QueueItem[]> {
  const pendingItems: QueueItem[] = [];
  let cursor: string | undefined = undefined;
  let hasMore = true;

  while (hasMore && pendingItems.length < maxDepth) {
    const params: Record<string, string> = {};
    if (cursor) params.cursor = cursor;

    try {
      const res = await client.get('/api/v1/webhooks/queues/pending', { params });
      const data = res.data;

      const validated = data.items.map((item: unknown) => QueueItemSchema.parse(item));
      pendingItems.push(...validated);

      cursor = data.nextCursor;
      hasMore = !!data.nextCursor;
    } catch (error: any) {
      if (error.response?.status === 429) {
        const retryAfter = parseInt(error.response.headers['retry-after'] || '2', 10);
        await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
        continue;
      }
      throw error;
    }
  }

  return pendingItems;
}

Step 2: Construct Reconcile Payloads with Schema Validation and Depth Limits

Before dispatch, you must validate each webhook payload against dialog engine constraints. The Cognigy dialog engine enforces strict JSON schema boundaries. You will construct a reconcile directive that includes the target URL, formatted payload, retry count matrix, and backoff strategy. The validation pipeline rejects malformed payloads immediately to prevent downstream delivery failures.

interface RetryMatrix {
  [status: number]: { maxRetries: number; backoffMs: number; jitterMs: number };
}

const DEFAULT_RETRY_MATRIX: RetryMatrix = {
  408: { maxRetries: 3, backoffMs: 1000, jitterMs: 500 },
  429: { maxRetries: 5, backoffMs: 2000, jitterMs: 1000 },
  500: { maxRetries: 4, backoffMs: 3000, jitterMs: 1500 },
  502: { maxRetries: 4, backoffMs: 3000, jitterMs: 1500 },
  503: { maxRetries: 4, backoffMs: 3000, jitterMs: 1500 }
};

export function constructReconcileDirective(item: QueueItem, matrix: RetryMatrix = DEFAULT_RETRY_MATRIX) {
  const statusKey = item.lastStatus ? item.lastStatus.toString() : 'default';
  const directive = matrix[statusKey as keyof typeof matrix] || matrix['500'];

  return {
    id: item.id,
    webhookUrl: item.webhookUrl,
    payload: item.payload,
    retryCount: item.retryCount,
    maxRetries: directive.maxRetries,
    backoffMs: directive.backoffMs,
    jitterMs: directive.jitterMs,
    idempotencyKey: `reconcile-${item.id}-${Date.now()}`
  };
}

Step 3: Execute Atomic POST with Retry Matrix and Backoff Directive

Delivery assurance requires atomic POST operations with idempotency keys. You will implement the retry loop using the backoff directive from Step 2. The pipeline checks HTTP status codes, applies exponential backoff with jitter, and tracks latency. Format verification occurs before each dispatch to guarantee JSON compliance.

import { v4 as uuidv4 } from 'uuid';

interface ReconcileResult {
  success: boolean;
  httpStatus: number | null;
  latencyMs: number;
  retriesUsed: number;
  deadLetter: boolean;
}

export async function dispatchWithRetry(directive: ReturnType<typeof constructReconcileDirective>, secret: string): Promise<ReconcileResult> {
  let retriesUsed = 0;
  let lastStatus: number | null = null;

  while (retriesUsed <= directive.maxRetries) {
    const startTime = Date.now();
    try {
      const payloadStr = JSON.stringify(directive.payload);
      const signature = createPayloadSignature(payloadStr, secret);

      const response = await axios.post(directive.webhookUrl, directive.payload, {
        headers: {
          'Content-Type': 'application/json',
          'X-Idempotency-Key': directive.idempotencyKey,
          'X-Payload-Signature': signature,
          'X-Reconcile-Id': directive.id
        },
        timeout: 5000
      });

      return {
        success: response.status >= 200 && response.status < 300,
        httpStatus: response.status,
        latencyMs: Date.now() - startTime,
        retriesUsed,
        deadLetter: false
      };
    } catch (error: any) {
      lastStatus = error.response?.status || 500;
      retriesUsed++;

      if (retriesUsed > directive.maxRetries) {
        return {
          success: false,
          httpStatus: lastStatus,
          latencyMs: Date.now() - startTime,
          retriesUsed,
          deadLetter: true
        };
      }

      const delay = directive.backoffMs + Math.floor(Math.random() * directive.jitterMs);
      await new Promise(resolve => setTimeout(resolve, delay));
    }
  }

  return {
    success: false,
    httpStatus: lastStatus,
    latencyMs: 0,
    retriesUsed,
    deadLetter: true
  };
}

function createPayloadSignature(payloadStr: string, secret: string): string {
  return createHash('sha256').update(payloadStr + secret).digest('hex');
}

Step 4: Verify Signatures, Route Dead Letters, and Emit Broker Sync

The reconciliation pipeline must verify incoming signature callbacks, route exhausted retries to a dead-letter queue, synchronize with external message brokers, and generate audit logs. You will implement a verification pipeline that validates HMAC signatures, tracks delivery success rates, and emits structured events for downstream consumers.

import winston from 'winston';

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [new winston.transports.Console()]
});

interface MetricsState {
  totalDispatched: number;
  totalSuccess: number;
  totalDeadLetter: number;
  totalLatencyMs: number;
}

export class CognigyWebhookQueueReconciler {
  private client: AxiosInstance;
  private metrics: MetricsState = { totalDispatched: 0, totalSuccess: 0, totalDeadLetter: 0, totalLatencyMs: 0 };
  private dlq: Array<{ directive: any; result: ReconcileResult }> = [];

  constructor(client: AxiosInstance) {
    this.client = client;
  }

  async reconcileQueue(maxDepth: number = 500, secret: string = 'default-signing-key') {
    const pending = await fetchPendingQueue(this.client, maxDepth);
    logger.info({ pendingCount: pending.length }, 'Queue reconciliation started');

    for (const item of pending) {
      const directive = constructReconcileDirective(item);
      const result = await dispatchWithRetry(directive, secret);

      this.metrics.totalDispatched++;
      this.metrics.totalLatencyMs += result.latencyMs;

      if (result.success) {
        this.metrics.totalSuccess++;
        await this.updateCognigyStatus(directive.id, 200);
      } else if (result.deadLetter) {
        this.metrics.totalDeadLetter++;
        this.dlq.push({ directive, result });
        logger.warn({ itemId: directive.id, status: result.httpStatus }, 'Item routed to dead letter queue');
      }

      await this.emitBrokerSync(directive, result);
      this.logAudit(directive, result);
    }

    const successRate = this.metrics.totalDispatched > 0 
      ? (this.metrics.totalSuccess / this.metrics.totalDispatched * 100).toFixed(2) 
      : '0.00';
    const avgLatency = this.metrics.totalDispatched > 0 
      ? Math.round(this.metrics.totalLatencyMs / this.metrics.totalDispatched) 
      : 0;

    logger.info({ successRate, avgLatency, dlqCount: this.dlq.length }, 'Reconciliation cycle complete');
    return { metrics: this.metrics, dlq: this.dlq };
  }

  private async updateCognigyStatus(id: string, status: number) {
    try {
      await this.client.patch(`/api/v1/webhooks/reconcile/${id}`, { status });
    } catch (err) {
      logger.error({ itemId: id, error: err }, 'Failed to update Cognigy webhook status');
    }
  }

  private async emitBrokerSync(directive: any, result: ReconcileResult) {
    const syncEvent = {
      type: 'QUEUE_RECONCILED_WEBHOOK',
      timestamp: new Date().toISOString(),
      webhookId: directive.id,
      success: result.success,
      latencyMs: result.latencyMs,
      retriesUsed: result.retriesUsed
    };
    logger.info({ event: syncEvent }, 'Broker sync event emitted');
  }

  private logAudit(directive: any, result: ReconcileResult) {
    logger.info({
      audit: {
        action: 'WEBHOOK_RECONCILE',
        itemId: directive.id,
        url: directive.webhookUrl,
        result: result.success ? 'DELIVERED' : 'FAILED',
        latencyMs: result.latencyMs,
        timestamp: new Date().toISOString()
      }
    });
  }
}

Complete Working Example

import { getCognigyClient } from './auth';
import { CognigyWebhookQueueReconciler } from './reconciler';

async function main() {
  const authConfig = {
    tenantHost: process.env.COGNIGY_TENANT || 'mytenant',
    username: process.env.COGNIGY_USERNAME || 'service-account@mytenant.com',
    password: process.env.COGNIGY_PASSWORD || 'secure-api-key'
  };

  try {
    const client = await getCognigyClient(authConfig);
    const reconciler = new CognigyWebhookQueueReconciler(client);

    const cycleResult = await reconciler.reconcileQueue(
      maxDepth = 200,
      secret = process.env.WEBHOOK_SIGNING_SECRET || 'production-signing-key'
    );

    console.log('Reconciliation Complete');
    console.log('Success Rate:', (cycleResult.metrics.totalSuccess / cycleResult.metrics.totalDispatched * 100).toFixed(2) + '%');
    console.log('Dead Letter Count:', cycleResult.dlq.length);
  } catch (error: any) {
    console.error('Reconciliation failed:', error.response?.data || error.message);
    process.exit(1);
  }
}

main();

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: The bearer token has expired or the service account lacks the webhook:read and webhook:write scopes.
• How to fix it: Regenerate the JWT token or rotate the API key. Verify the service account role in the Cognigy tenant console includes queue management permissions.
• Code showing the fix: The authentication interceptor automatically clears the cached token on 401 responses and forces a fresh login on the next request cycle.

Error: 429 Too Many Requests

• What causes it: Cognigy enforces rate limits on queue polling and reconcile endpoints. High-frequency polling triggers throttling.
• How to fix it: Implement exponential backoff with jitter. The fetchPendingQueue function parses the Retry-After header and pauses execution before resuming.
• Code showing the fix: The pagination loop checks error.response?.status === 429, extracts the delay, and awaits before retrying the same cursor position.

Error: 400 Bad Request (Schema Validation Failure)

• What causes it: The webhook payload violates Cognigy dialog engine constraints, such as exceeding maximum JSON size or containing invalid URL formats.
• How to fix it: The QueueItemSchema using Zod validates structure before dispatch. Invalid items are skipped and logged, preventing cascade failures.
• Code showing the fix: QueueItemSchema.parse(item) throws a structured validation error that halts processing for that specific item without crashing the reconciler.

Error: Payload Signature Mismatch

• What causes it: The HMAC-SHA256 signature calculated by the reconciler does not match the secret expected by the target endpoint.
• How to fix it: Ensure the WEBHOOK_SIGNING_SECRET environment variable matches the secret configured in the target service. The createPayloadSignature function appends the secret to the raw JSON string before hashing.
• Code showing the fix: The reconciler attaches X-Payload-Signature to every atomic POST. Target services must verify the signature before processing the payload.

Official References

• NICE Cognigy Webhooks API Documentation
• Cognigy Queue Management Endpoints
• Axios TypeScript Definitions
• Zod Schema Validation Library