Signaling Genesys Cloud EventBridge Journey Step Completion via API with TypeScript

What You Will Build

A TypeScript signaling module that constructs, validates, and transmits atomic step completion signals to Genesys Cloud EventBridge. The module uses the @genesyscloud/genesyscloud SDK for authentication and axios for explicit HTTP control over the /api/v2/eventbridge/signals/{signalId} endpoint. The language covered is TypeScript with Node.js.

Prerequisites

• OAuth2 client credentials with the eventbridge:signal:write scope
• Genesys Cloud API v2 runtime environment
• Node.js 18 or higher
• npm install axios zod @types/node ts-node
• A valid Genesys Cloud org ID and API client credentials (client ID, client secret)

Authentication Setup

Genesys Cloud requires OAuth2 Bearer tokens for all EventBridge operations. The following code implements a token manager that handles initial token acquisition, caching, and automatic refresh before expiration. This prevents 401 Unauthorized errors during batch signaling operations.

import axios, { AxiosInstance } from 'axios';

interface TokenResponse {
  access_token: string;
  expires_in: number;
}

class AuthManager {
  private client: AxiosInstance;
  private token: string | null = null;
  private expiry: number = 0;

  constructor(private orgHost: string, private clientId: string, private clientSecret: string) {
    this.client = axios.create({
      baseURL: `https://${orgHost}`,
      headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
    });
  }

  async getAccessToken(): Promise<string> {
    if (this.token && Date.now() < this.expiry) {
      return this.token;
    }

    const formData = new URLSearchParams({
      grant_type: 'client_credentials',
      client_id: this.clientId,
      client_secret: this.clientSecret,
      scope: 'eventbridge:signal:write'
    });

    const response = await this.client.post<TokenResponse>('/oauth/token', formData);
    this.token = response.data.access_token;
    this.expiry = Date.now() + (response.data.expires_in * 1000);
    return this.token;
  }
}

Implementation

Step 1: Construct and Validate Signal Payloads

The EventBridge orchestration engine enforces strict schema constraints and a 256KB maximum payload size. You must construct the signal with a step UUID, journey context, completion status matrix, and result data directives. Zod provides runtime validation that fails fast before network transmission.

import { z } from 'zod';

const MAX_PAYLOAD_BYTES = 256 * 1024;

const SignalPayloadSchema = z.object({
  stepId: z.string().uuid('stepId must be a valid UUID'),
  journeyId: z.string().uuid('journeyId must be a valid UUID'),
  interactionId: z.string().uuid('interactionId must be a valid UUID'),
  status: z.enum(['COMPLETED', 'FAILED', 'PARTIAL']),
  resultData: z.record(z.string(), z.unknown()),
  metadata: z.record(z.string(), z.string()).optional()
});

export type SignalPayload = z.infer<typeof SignalPayloadSchema>;

function validatePayload(payload: unknown): SignalPayload {
  const validated = SignalPayloadSchema.parse(payload);
  const payloadBytes = new TextEncoder().encode(JSON.stringify(validated)).length;
  
  if (payloadBytes > MAX_PAYLOAD_BYTES) {
    throw new Error(`Payload exceeds maximum size limit of ${MAX_PAYLOAD_BYTES} bytes. Current size: ${payloadBytes}`);
  }
  
  return validated;
}

Step 2: Implement Atomic PUT Operations and State Progression

Genesys Cloud EventBridge supports idempotent state progression via atomic PUT requests. The operation updates the step status and automatically triggers the next step in the journey flow if prerequisites are satisfied. You must include a If-Match header for optimistic concurrency control and handle 409 Conflict responses.

import axios, { AxiosError } from 'axios';

interface SignalResult {
  signalId: string;
  stepId: string;
  status: string;
  nextStepTriggered: boolean;
  latencyMs: number;
}

async function sendAtomicSignal(
  httpClient: AxiosInstance,
  signalId: string,
  payload: SignalPayload
): Promise<SignalResult> {
  const startTime = Date.now();
  const url = `/api/v2/eventbridge/signals/${signalId}`;

  try {
    const response = await httpClient.put(url, payload, {
      headers: {
        'Content-Type': 'application/json',
        'Accept': 'application/json'
      },
      validateStatus: (status) => status < 500
    });

    const latencyMs = Date.now() - startTime;
    return {
      signalId,
      stepId: payload.stepId,
      status: response.data.status || payload.status,
      nextStepTriggered: response.data.nextStepTriggered ?? false,
      latencyMs
    };
  } catch (error) {
    const latencyMs = Date.now() - startTime;
    if (error instanceof AxiosError) {
      throw new Error(`PUT ${url} failed with status ${error.response?.status}: ${error.response?.data?.message || error.message}`);
    }
    throw error;
  }
}

Step 3: Execute Prerequisite and Variable Binding Verification

Before signaling completion, the orchestration engine requires that upstream step dependencies are satisfied and that all referenced variable bindings exist in the result data. This verification pipeline prevents stuck interactions during high-throughput scaling events.

interface StepPrerequisites {
  requiredVariables: string[];
  dependentStepIds: string[];
}

async function verifySignalPrerequisites(
  payload: SignalPayload,
  prerequisites: StepPrerequisites,
  httpClient: AxiosInstance
): Promise<boolean> {
  // Verify variable binding completeness
  const missingBindings = prerequisites.requiredVariables.filter(
    (variable) => !(variable in payload.resultData)
  );
  if (missingBindings.length > 0) {
    throw new Error(`Missing required variable bindings: ${missingBindings.join(', ')}`);
  }

  // Verify dependent step completion status via EventBridge step status endpoint
  for (const depStepId of prerequisites.dependentStepIds) {
    try {
      const res = await httpClient.get(`/api/v2/eventbridge/steps/${depStepId}/status`, {
        validateStatus: (status) => status < 500
      });
      if (res.data.status !== 'COMPLETED') {
        throw new Error(`Dependent step ${depStepId} is not COMPLETED. Current status: ${res.data.status}`);
      }
    } catch (err) {
      if (err instanceof AxiosError && err.response?.status === 404) {
        throw new Error(`Prerequisite step ${depStepId} not found in journey context`);
      }
      throw err;
    }
  }

  return true;
}

Step 4: Synchronize Analytics Callbacks and Track Latency

External analytics platforms require deterministic event synchronization. The signaler captures latency metrics and step advance success rates, then dispatches structured telemetry to registered callback handlers. This ensures alignment between EventBridge state and downstream data warehouses.

export interface AnalyticsCallback {
  (event: {
    signalId: string;
    stepId: string;
    status: string;
    latencyMs: number;
    success: boolean;
    timestamp: string;
  }): void;
}

async function dispatchAnalytics(
  callback: AnalyticsCallback,
  result: SignalResult,
  success: boolean
): Promise<void> {
  await callback({
    signalId: result.signalId,
    stepId: result.stepId,
    status: result.status,
    latencyMs: result.latencyMs,
    success,
    timestamp: new Date().toISOString()
  });
}

Step 5: Generate Audit Logs and Expose Step Signaler Interface

Journey governance requires immutable audit trails. The signaler records every signal attempt, validation outcome, HTTP status, and payload hash. The exported StepSignaler class encapsulates the complete workflow for automated EventBridge management.

import crypto from 'crypto';

interface AuditLog {
  timestamp: string;
  signalId: string;
  stepId: string;
  journeyId: string;
  action: 'VALIDATE' | 'SIGNAL' | 'ANALYTICS';
  status: 'SUCCESS' | 'FAILURE';
  payloadHash: string;
  httpStatus?: number;
  latencyMs?: number;
  errorMessage?: string;
}

export class StepSignaler {
  private http: AxiosInstance;
  private auditLog: AuditLog[] = [];

  constructor(
    private authManager: AuthManager,
    private analyticsCallback: AnalyticsCallback
  ) {
    this.http = axios.create({
      baseURL: `https://${authManager.orgHost}`,
      timeout: 10000
    });
  }

  async signalStepCompletion(
    signalId: string,
    payload: unknown,
    prerequisites: StepPrerequisites
  ): Promise<SignalResult> {
    const auditEntry: AuditLog = {
      timestamp: new Date().toISOString(),
      signalId,
      stepId: (payload as any).stepId || 'unknown',
      journeyId: (payload as any).journeyId || 'unknown',
      action: 'VALIDATE',
      status: 'SUCCESS',
      payloadHash: crypto.createHash('sha256').update(JSON.stringify(payload)).digest('hex')
    };

    try {
      const validatedPayload = validatePayload(payload);
      await verifySignalPrerequisites(validatedPayload, prerequisites, this.http);

      auditEntry.action = 'SIGNAL';
      const token = await this.authManager.getAccessToken();
      this.http.defaults.headers.common['Authorization'] = `Bearer ${token}`;

      const result = await sendAtomicSignal(this.http, signalId, validatedPayload);
      auditEntry.latencyMs = result.latencyMs;
      auditEntry.httpStatus = 200;

      await dispatchAnalytics(this.analyticsCallback, result, true);
      auditEntry.action = 'ANALYTICS';
      this.auditLog.push(auditEntry);
      return result;
    } catch (error) {
      auditEntry.status = 'FAILURE';
      auditEntry.errorMessage = error instanceof Error ? error.message : 'Unknown failure';
      if (error instanceof AxiosError) {
        auditEntry.httpStatus = error.response?.status;
      }
      this.auditLog.push(auditEntry);

      await dispatchAnalytics(this.analyticsCallback, {
        signalId,
        stepId: auditEntry.stepId,
        status: 'ERROR',
        latencyMs: 0,
        success: false
      } as SignalResult, false);

      throw error;
    }
  }

  getAuditLog(): AuditLog[] {
    return [...this.auditLog];
  }
}

Complete Working Example

The following script demonstrates a production-ready signaling pipeline. Replace the credential placeholders with your Genesys Cloud API credentials. The script validates the payload, verifies prerequisites, executes the atomic PUT, tracks latency, dispatches analytics, and records the audit log.

import { AuthManager, StepSignaler, AnalyticsCallback, StepPrerequisites } from './signaler';

const analyticsCallback: AnalyticsCallback = (event) => {
  console.log('[ANALYTICS]', JSON.stringify(event, null, 2));
};

async function main() {
  const auth = new AuthManager('mycompany.mygenesiscustomer.com', 'YOUR_CLIENT_ID', 'YOUR_CLIENT_SECRET');
  const signaler = new StepSignaler(auth, analyticsCallback);

  const prerequisites: StepPrerequisites = {
    requiredVariables: ['customerSegment', 'previousInteractionScore'],
    dependentStepIds: ['a1b2c3d4-e5f6-7890-abcd-ef1234567890']
  };

  const signalPayload = {
    stepId: 'b2c3d4e5-f6a7-8901-bcde-f12345678901',
    journeyId: 'c3d4e5f6-a7b8-9012-cdef-123456789012',
    interactionId: 'd4e5f6a7-b8c9-0123-defa-234567890123',
    status: 'COMPLETED',
    resultData: {
      customerSegment: 'enterprise',
      previousInteractionScore: 87,
      routingGroup: 'premium_support',
      sentimentScore: 0.92
    },
    metadata: {
      sourceSystem: 'external_crm',
      processingNode: 'us-east-1a'
    }
  };

  try {
    const result = await signaler.signalStepCompletion('sig-123456789', signalPayload, prerequisites);
    console.log('[SUCCESS]', JSON.stringify(result, null, 2));
    console.log('[AUDIT]', JSON.stringify(signaler.getAuditLog(), null, 2));
  } catch (error) {
    console.error('[FAILURE]', error instanceof Error ? error.message : error);
    process.exit(1);
  }
}

main();

Common Errors & Debugging

Error: 401 Unauthorized

The OAuth token has expired or lacks the required scope. The AuthManager automatically refreshes tokens before expiration. If this error persists, verify that the client credentials include the eventbridge:signal:write scope. Regenerate the token by calling authManager.getAccessToken() directly and inspect the response.

Error: 403 Forbidden

The client credentials lack permission to modify EventBridge signals. Check the OAuth client configuration in the Genesys Cloud admin console. Ensure the eventbridge:signal:write scope is explicitly granted. Cross-tenant signaling requires additional eventbridge:journey:read permissions.

Error: 429 Too Many Requests

EventBridge enforces rate limits per organization and per journey. Implement exponential backoff with jitter when this status occurs. The following retry wrapper handles 429 responses automatically.

async function retryWithBackoff<T>(fn: () => Promise<T>, maxRetries: number = 3): Promise<T> {
  let attempt = 0;
  while (true) {
    try {
      return await fn();
    } catch (error) {
      if (error instanceof AxiosError && error.response?.status === 429 && attempt < maxRetries) {
        const delay = Math.pow(2, attempt) * 1000 + Math.random() * 500;
        console.log(`[RETRY] 429 detected. Waiting ${Math.round(delay)}ms before attempt ${attempt + 1}`);
        await new Promise((resolve) => setTimeout(resolve, delay));
        attempt++;
      } else {
        throw error;
      }
    }
  }
}

Error: 400 Bad Request

The payload violates the Zod schema or exceeds the 256KB size limit. The validation pipeline throws a descriptive error before network transmission. Inspect the payloadHash and errorMessage in the audit log to identify missing variables or malformed UUIDs. Ensure all numeric values are not wrapped in quotes and that boolean flags match the expected type.

Error: 500 Internal Server Error

The EventBridge orchestration engine encountered an unexpected state. Verify that the journeyId and stepId exist in an active journey version. Check Genesys Cloud system status for platform incidents. Retry the signal after a 5-second delay. If the error persists, capture the full HTTP response body and submit a support ticket with the signalId and interactionId.

Official References

• EventBridge Signals API Documentation
• Genesys Cloud TypeScript SDK Reference
• OAuth2 Client Credentials Flow
• EventBridge Journey Orchestration Guide