Replaying NICE CXone Pure Connect IVR Call Flows via Pure Connect APIs with Go

What You Will Build

• This tutorial builds a production-grade Go module that programmatically replays Pure Connect IVR flows by submitting structured simulation payloads to the CXone API.
• The implementation uses the NICE CXone Pure Connect Flow Simulation API (POST /api/v2/flows/simulate) and OAuth 2.0 Client Credentials authentication.
• The programming language covered is Go 1.21+, using only standard library packages for maximum portability and zero external dependencies.

Prerequisites

• OAuth 2.0 Client Credentials grant type with scopes: flow:read, flow:simulate, analytics:read
• CXone Pure Connect API v2 (region-specific base URL, e.g., us2.nicecxone.com)
• Go 1.21 or newer
• No external packages required. All dependencies are from the standard library (net/http, encoding/json, context, time, fmt, log, os, sync, math, crypto/rand).

Authentication Setup

CXone uses a standard OAuth 2.0 token endpoint. The client credentials flow returns a short-lived access token that must be cached and refreshed before expiration. The code below implements a thread-safe token cache with automatic refresh logic.

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"sync"
	"time"
)

type OAuthConfig struct {
	BaseURL    string
	ClientID   string
	ClientSec  string
	GrantType  string
	Scope      string
}

type TokenResponse struct {
	AccessToken string `json:"access_token"`
	TokenType   string `json:"token_type"`
	ExpiresIn   int    `json:"expires_in"`
}

type TokenManager struct {
	mu      sync.RWMutex
	token   TokenResponse
	config  OAuthConfig
	client  *http.Client
}

func NewTokenManager(cfg OAuthConfig) *TokenManager {
	return &TokenManager{
		config: cfg,
		client: &http.Client{Timeout: 10 * time.Second},
	}
}

func (tm *TokenManager) GetAccessToken(ctx context.Context) (string, error) {
	tm.mu.RLock()
	if tm.token.AccessToken != "" && time.Now().Before(tm.token.ExpiresAt) {
		token := tm.token.AccessToken
		tm.mu.RUnlock()
		return token, nil
	}
	tm.mu.RUnlock()

	tm.mu.Lock()
	defer tm.mu.Unlock()

	// Double-check after acquiring write lock
	if tm.token.AccessToken != "" && time.Now().Before(tm.token.ExpiresAt) {
		return tm.token.AccessToken, nil
	}

	body := fmt.Sprintf("client_id=%s&client_secret=%s&grant_type=%s&scope=%s",
		tm.config.ClientID, tm.config.ClientSec, tm.config.GrantType, tm.config.Scope)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tm.config.BaseURL+"/oauth/token",
		io.NopReader([]byte(body)))
	if err != nil {
		return "", fmt.Errorf("failed to build token request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

	resp, err := tm.client.Do(req)
	if err != nil {
		return "", fmt.Errorf("token request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("oauth 401/403: status %d", resp.StatusCode)
	}

	var tokenResp TokenResponse
	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
		return "", fmt.Errorf("token decode failed: %w", err)
	}

	tm.token = tokenResp
	tm.token.ExpiresAt = time.Now().Add(time.Duration(tokenResp.ExpiresIn-30) * time.Second)
	return tokenResp.AccessToken, nil
}

The TokenManager stores the expiration time with a 30-second safety buffer. This prevents race conditions where a request initiates exactly at token expiry. The OAuth scope flow:read flow:simulate is required for all subsequent replay operations.

Implementation

Step 1: Construct Replay Payloads with Flow References and Path Matrix

The CXone simulation engine expects a structured JSON payload containing the target flow identifier, a simulation directive, and a path matrix that defines the exact node traversal sequence. The path matrix maps directly to Pure Connect flow builder node IDs.

type SimulatePayload struct {
	FlowID     string            `json:"flowId"`
	Simulate   SimulateDirective `json:"simulate"`
	Inputs     SimulateInputs    `json:"inputs"`
	Metadata   map[string]string `json:"metadata,omitempty"`
}

type SimulateDirective struct {
	Type              string   `json:"type"`
	PathMatrix        []string `json:"pathMatrix"`
	MaxNodeTraversal  int      `json:"maxNodeTraversal"`
	TimeoutThreshold  int      `json:"timeoutThreshold"`
	EnableErrorInject bool     `json:"enableErrorInject"`
}

type SimulateInputs struct {
	DTMF          []string `json:"dtmf"`
	PromptDelayMs int      `json:"promptPlaybackDelay"`
	Language      string   `json:"language"`
}

func BuildReplayPayload(flowID string, path []string, dtmf []string) SimulatePayload {
	return SimulatePayload{
		FlowID: flowID,
		Simulate: SimulateDirective{
			Type:              "replay",
			PathMatrix:        path,
			MaxNodeTraversal:  100,
			TimeoutThreshold:  45000,
			EnableErrorInject: true,
		},
		Inputs: SimulateInputs{
			DTMF:          dtmf,
			PromptDelayMs: 500,
			Language:      "en-US",
		},
		Metadata: map[string]string{
			"replaySource": "go-automation",
			"qaFramework":  "external-test-suite",
		},
	}
}

The SimulateDirective enforces a maximum node traversal limit to prevent infinite loops during replay. The TimeoutThreshold value is specified in milliseconds and caps the total simulation duration. The EnableErrorInject flag allows the CXone engine to safely inject synthetic failures at decision nodes without impacting production routing.

Step 2: Validate Replay Schemas Against Simulation Constraints

Before submitting the payload, the code validates structural consistency. This prevents 400 Bad Request responses caused by malformed path matrices or conflicting simulation parameters.

type ValidationErr struct {
	Message string
	Code    string
}

func (e ValidationErr) Error() string { return e.Message }

func ValidateReplaySchema(payload SimulatePayload) error {
	if payload.FlowID == "" {
		return ValidationErr{Message: "flowId cannot be empty", Code: "MISSING_FLOW_ID"}
	}
	if len(payload.Simulate.PathMatrix) == 0 {
		return ValidationErr{Message: "pathMatrix requires at least one node", Code: "EMPTY_PATH_MATRIX"}
	}
	if payload.Simulate.MaxNodeTraversal <= 0 || payload.Simulate.MaxNodeTraversal > 500 {
		return ValidationErr{Message: "maxNodeTraversal must be between 1 and 500", Code: "INVALID_TRAVERSAL_LIMIT"}
	}
	if len(payload.Simulate.PathMatrix) > payload.Simulate.MaxNodeTraversal {
		return ValidationErr{Message: "pathMatrix exceeds maxNodeTraversal limit", Code: "PATH_EXCEEDS_LIMIT"}
	}
	if payload.Simulate.TimeoutThreshold < 5000 || payload.Simulate.TimeoutThreshold > 120000 {
		return ValidationErr{Message: "timeoutThreshold must be between 5000 and 120000 ms", Code: "INVALID_TIMEOUT"}
	}
	for _, key := range payload.Simulate.PathMatrix {
		if key == "" {
			return ValidationErr{Message: "pathMatrix contains empty node identifier", Code: "INVALID_NODE_ID"}
		}
	}
	return nil
}

This validation layer enforces business rules before network I/O occurs. The CXone API rejects payloads where the path matrix length exceeds the traversal limit, so the check here saves a round trip. The timeout threshold boundaries align with CXone platform limits to prevent gateway timeouts.

Step 3: Execute Atomic POST Operations with DTMF and Timing Logic

The simulation endpoint processes the payload atomically. The Go client implements exponential backoff for 429 responses and retries transient 5xx errors. DTMF sequences and prompt delays are embedded directly in the payload, allowing the simulation engine to replay caller interactions deterministically.

type SimulationResult struct {
	Status          string            `json:"status"`
	FlowID          string            `json:"flowId"`
	ExecutionTimeMs int               `json:"executionTimeMs"`
	NodeResults     []NodeResult      `json:"nodeResults"`
	Errors          []string          `json:"errors,omitempty"`
	WebhookSynced   bool              `json:"webhookSynced"`
	AuditID         string            `json:"auditId"`
}

type NodeResult struct {
	NodeID   string `json:"nodeId"`
	Status   string `json:"status"`
	Duration int    `json:"durationMs"`
}

func ExecuteSimulation(ctx context.Context, tm *TokenManager, apiBase string, payload SimulatePayload) (*SimulationResult, error) {
	if err := ValidateReplaySchema(payload); err != nil {
		return nil, err
	}

	token, err := tm.GetAccessToken(ctx)
	if err != nil {
		return nil, fmt.Errorf("authentication failed: %w", err)
	}

	jsonBody, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("payload marshal failed: %w", err)
	}

	url := fmt.Sprintf("%s/api/v2/flows/simulate", apiBase)
	var result *SimulationResult
	maxRetries := 3

	for attempt := 0; attempt <= maxRetries; attempt++ {
		req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, io.NopReader(jsonBody))
		if err != nil {
			return nil, fmt.Errorf("request build failed: %w", err)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Authorization", "Bearer "+token)

		client := &http.Client{Timeout: time.Duration(payload.Simulate.TimeoutThreshold+5000) * time.Millisecond}
		resp, err := client.Do(req)
		if err != nil {
			if attempt < maxRetries {
				time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
				continue
			}
			return nil, fmt.Errorf("network error: %w", err)
		}
		defer resp.Body.Close()

		body, _ := io.ReadAll(resp.Body)

		switch resp.StatusCode {
		case http.StatusOK:
			if err := json.Unmarshal(body, &result); err != nil {
				return nil, fmt.Errorf("response decode failed: %w", err)
			}
			return result, nil
		case http.StatusTooManyRequests:
			time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
			continue
		case http.StatusUnauthorized:
			tm.mu.Lock()
			tm.token.AccessToken = ""
			tm.mu.Unlock()
			token, err = tm.GetAccessToken(ctx)
			if err != nil {
				return nil, err
			}
			req.Header.Set("Authorization", "Bearer "+token)
			continue
		case http.StatusBadRequest:
			return nil, fmt.Errorf("schema validation rejected: %s", string(body))
		default:
			if resp.StatusCode >= 500 && attempt < maxRetries {
				time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
				continue
			}
			return nil, fmt.Errorf("api error %d: %s", resp.StatusCode, string(body))
		}
	}
	return nil, fmt.Errorf("max retries exceeded for simulation")
}

The retry logic handles rate limiting and transient server errors. The timeout for the HTTP client exceeds the simulation threshold by 5 seconds to account for network latency. The 401 handler invalidates the cached token and forces a refresh. The 429 handler applies exponential backoff to prevent cascading rate-limit blocks across microservices.

Step 4: Implement State Machine Consistency and Timeout Verification

After the simulation completes, the code verifies state machine consistency. This ensures the returned node results follow the expected path matrix and that no simulation hang occurred.

func VerifySimulationState(result *SimulationResult, expectedPath []string) error {
	if result.Status != "completed" {
		return fmt.Errorf("simulation did not complete: status=%s", result.Status)
	}
	if result.ExecutionTimeMs > 45000 {
		return fmt.Errorf("timeout threshold exceeded: %d ms", result.ExecutionTimeMs)
	}
	if len(result.NodeResults) == 0 {
		return fmt.Errorf("empty node results array")
	}

	// Verify path consistency
	var traversed []string
	for _, nr := range result.NodeResults {
		traversed = append(traversed, nr.NodeID)
	}
	for i, node := range expectedPath {
		if i >= len(traversed) {
			return fmt.Errorf("path matrix mismatch at index %d: expected %s", i, node)
		}
		if traversed[i] != node {
			return fmt.Errorf("node traversal deviation at index %d: expected %s, got %s", i, node, traversed[i])
		}
	}
	return nil
}

This verification step catches simulation hangs and routing deviations. The CXone engine may skip nodes under certain error injection conditions, so the validation checks for exact path alignment. The timeout threshold verification prevents resource exhaustion during automated scaling tests.

Step 5: Synchronize Events and Generate Audit Logs

The final step posts the simulation result to an external QA framework webhook and writes a structured audit log for testing governance. This enables traceability across automated test pipelines.

func SyncWebhookAndAudit(ctx context.Context, result *SimulationResult, webhookURL string, auditDir string) error {
	// Webhook sync
	webhookPayload := map[string]interface{}{
		"eventType":     "flow.replay.completed",
		"flowId":        result.FlowID,
		"status":        result.Status,
		"executionTime": result.ExecutionTimeMs,
		"timestamp":     time.Now().UTC().Format(time.RFC3339),
	}
	jsonPayload, _ := json.Marshal(webhookPayload)

	req, _ := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, io.NopReader(jsonPayload))
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("webhook sync failed: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 300 {
		return fmt.Errorf("webhook rejected: %d", resp.StatusCode)
	}

	// Audit log
	auditEntry := map[string]interface{}{
		"auditId":         result.AuditID,
		"flowId":          result.FlowID,
		"status":          result.Status,
		"executionMs":     result.ExecutionTimeMs,
		"nodeCount":       len(result.NodeResults),
		"timestamp":       time.Now().UTC().Format(time.RFC3339),
		"source":          "go-replayer",
	}
	auditJSON, _ := json.MarshalIndent(auditEntry, "", "  ")
	filename := fmt.Sprintf("%s/audit_%s_%d.json", auditDir, result.FlowID, time.Now().UnixNano())
	if err := os.WriteFile(filename, auditJSON, 0644); err != nil {
		return fmt.Errorf("audit write failed: %w", err)
	}
	return nil
}

The webhook payload follows a standard event schema compatible with most QA aggregation frameworks. The audit log persists execution metrics for compliance reviews and performance trending. Both operations use short timeouts to prevent blocking the main replay pipeline.

Complete Working Example

The following script combines all components into a single executable module. Replace the environment variables with your CXone credentials before execution.

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"math"
	"net/http"
	"os"
	"sync"
	"time"
)

// Types
type OAuthConfig struct {
	BaseURL   string
	ClientID  string
	ClientSec string
	GrantType string
	Scope     string
}

type TokenResponse struct {
	AccessToken string `json:"access_token"`
	TokenType   string `json:"token_type"`
	ExpiresIn   int    `json:"expires_in"`
	ExpiresAt   time.Time
}

type TokenManager struct {
	mu     sync.RWMutex
	token  TokenResponse
	config OAuthConfig
	client *http.Client
}

type SimulatePayload struct {
	FlowID   string            `json:"flowId"`
	Simulate SimulateDirective `json:"simulate"`
	Inputs   SimulateInputs    `json:"inputs"`
	Metadata map[string]string `json:"metadata,omitempty"`
}

type SimulateDirective struct {
	Type              string   `json:"type"`
	PathMatrix        []string `json:"pathMatrix"`
	MaxNodeTraversal  int      `json:"maxNodeTraversal"`
	TimeoutThreshold  int      `json:"timeoutThreshold"`
	EnableErrorInject bool     `json:"enableErrorInject"`
}

type SimulateInputs struct {
	DTMF          []string `json:"dtmf"`
	PromptDelayMs int      `json:"promptPlaybackDelay"`
	Language      string   `json:"language"`
}

type SimulationResult struct {
	Status          string       `json:"status"`
	FlowID          string       `json:"flowId"`
	ExecutionTimeMs int          `json:"executionTimeMs"`
	NodeResults     []NodeResult `json:"nodeResults"`
	Errors          []string     `json:"errors,omitempty"`
	WebhookSynced   bool         `json:"webhookSynced"`
	AuditID         string       `json:"auditId"`
}

type NodeResult struct {
	NodeID   string `json:"nodeId"`
	Status   string `json:"status"`
	Duration int    `json:"durationMs"`
}

type ValidationErr struct {
	Message string
	Code    string
}

func (e ValidationErr) Error() string { return e.Message }

// Token Manager
func NewTokenManager(cfg OAuthConfig) *TokenManager {
	return &TokenManager{
		config: cfg,
		client: &http.Client{Timeout: 10 * time.Second},
	}
}

func (tm *TokenManager) GetAccessToken(ctx context.Context) (string, error) {
	tm.mu.RLock()
	if tm.token.AccessToken != "" && time.Now().Before(tm.token.ExpiresAt) {
		token := tm.token.AccessToken
		tm.mu.RUnlock()
		return token, nil
	}
	tm.mu.RUnlock()

	tm.mu.Lock()
	defer tm.mu.Unlock()

	if tm.token.AccessToken != "" && time.Now().Before(tm.token.ExpiresAt) {
		return tm.token.AccessToken, nil
	}

	body := fmt.Sprintf("client_id=%s&client_secret=%s&grant_type=%s&scope=%s",
		tm.config.ClientID, tm.config.ClientSec, tm.config.GrantType, tm.config.Scope)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tm.config.BaseURL+"/oauth/token",
		io.NopReader([]byte(body)))
	if err != nil {
		return "", fmt.Errorf("failed to build token request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

	resp, err := tm.client.Do(req)
	if err != nil {
		return "", fmt.Errorf("token request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("oauth error: status %d", resp.StatusCode)
	}

	var tokenResp TokenResponse
	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
		return "", fmt.Errorf("token decode failed: %w", err)
	}

	tm.token = tokenResp
	tm.token.ExpiresAt = time.Now().Add(time.Duration(tokenResp.ExpiresIn-30) * time.Second)
	return tokenResp.AccessToken, nil
}

// Validation
func ValidateReplaySchema(payload SimulatePayload) error {
	if payload.FlowID == "" {
		return ValidationErr{Message: "flowId cannot be empty", Code: "MISSING_FLOW_ID"}
	}
	if len(payload.Simulate.PathMatrix) == 0 {
		return ValidationErr{Message: "pathMatrix requires at least one node", Code: "EMPTY_PATH_MATRIX"}
	}
	if payload.Simulate.MaxNodeTraversal <= 0 || payload.Simulate.MaxNodeTraversal > 500 {
		return ValidationErr{Message: "maxNodeTraversal must be between 1 and 500", Code: "INVALID_TRAVERSAL_LIMIT"}
	}
	if len(payload.Simulate.PathMatrix) > payload.Simulate.MaxNodeTraversal {
		return ValidationErr{Message: "pathMatrix exceeds maxNodeTraversal limit", Code: "PATH_EXCEEDS_LIMIT"}
	}
	if payload.Simulate.TimeoutThreshold < 5000 || payload.Simulate.TimeoutThreshold > 120000 {
		return ValidationErr{Message: "timeoutThreshold must be between 5000 and 120000 ms", Code: "INVALID_TIMEOUT"}
	}
	for _, key := range payload.Simulate.PathMatrix {
		if key == "" {
			return ValidationErr{Message: "pathMatrix contains empty node identifier", Code: "INVALID_NODE_ID"}
		}
	}
	return nil
}

func BuildReplayPayload(flowID string, path []string, dtmf []string) SimulatePayload {
	return SimulatePayload{
		FlowID: flowID,
		Simulate: SimulateDirective{
			Type:              "replay",
			PathMatrix:        path,
			MaxNodeTraversal:  100,
			TimeoutThreshold:  45000,
			EnableErrorInject: true,
		},
		Inputs: SimulateInputs{
			DTMF:          dtmf,
			PromptDelayMs: 500,
			Language:      "en-US",
		},
		Metadata: map[string]string{
			"replaySource": "go-automation",
			"qaFramework":  "external-test-suite",
		},
	}
}

// Execution
func ExecuteSimulation(ctx context.Context, tm *TokenManager, apiBase string, payload SimulatePayload) (*SimulationResult, error) {
	if err := ValidateReplaySchema(payload); err != nil {
		return nil, err
	}

	token, err := tm.GetAccessToken(ctx)
	if err != nil {
		return nil, fmt.Errorf("authentication failed: %w", err)
	}

	jsonBody, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("payload marshal failed: %w", err)
	}

	url := fmt.Sprintf("%s/api/v2/flows/simulate", apiBase)
	var result *SimulationResult
	maxRetries := 3

	for attempt := 0; attempt <= maxRetries; attempt++ {
		req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, io.NopReader(jsonBody))
		if err != nil {
			return nil, fmt.Errorf("request build failed: %w", err)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Authorization", "Bearer "+token)

		client := &http.Client{Timeout: time.Duration(payload.Simulate.TimeoutThreshold+5000) * time.Millisecond}
		resp, err := client.Do(req)
		if err != nil {
			if attempt < maxRetries {
				time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
				continue
			}
			return nil, fmt.Errorf("network error: %w", err)
		}
		defer resp.Body.Close()

		body, _ := io.ReadAll(resp.Body)

		switch resp.StatusCode {
		case http.StatusOK:
			if err := json.Unmarshal(body, &result); err != nil {
				return nil, fmt.Errorf("response decode failed: %w", err)
			}
			return result, nil
		case http.StatusTooManyRequests:
			time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
			continue
		case http.StatusUnauthorized:
			tm.mu.Lock()
			tm.token.AccessToken = ""
			tm.mu.Unlock()
			token, err = tm.GetAccessToken(ctx)
			if err != nil {
				return nil, err
			}
			req.Header.Set("Authorization", "Bearer "+token)
			continue
		case http.StatusBadRequest:
			return nil, fmt.Errorf("schema validation rejected: %s", string(body))
		default:
			if resp.StatusCode >= 500 && attempt < maxRetries {
				time.Sleep(time.Duration(math.Pow(2, float64(attempt))) * time.Second)
				continue
			}
			return nil, fmt.Errorf("api error %d: %s", resp.StatusCode, string(body))
		}
	}
	return nil, fmt.Errorf("max retries exceeded for simulation")
}

// Verification & Sync
func VerifySimulationState(result *SimulationResult, expectedPath []string) error {
	if result.Status != "completed" {
		return fmt.Errorf("simulation did not complete: status=%s", result.Status)
	}
	if result.ExecutionTimeMs > 45000 {
		return fmt.Errorf("timeout threshold exceeded: %d ms", result.ExecutionTimeMs)
	}
	if len(result.NodeResults) == 0 {
		return fmt.Errorf("empty node results array")
	}
	var traversed []string
	for _, nr := range result.NodeResults {
		traversed = append(traversed, nr.NodeID)
	}
	for i, node := range expectedPath {
		if i >= len(traversed) {
			return fmt.Errorf("path matrix mismatch at index %d: expected %s", i, node)
		}
		if traversed[i] != node {
			return fmt.Errorf("node traversal deviation at index %d: expected %s, got %s", i, node, traversed[i])
		}
	}
	return nil
}

func SyncWebhookAndAudit(ctx context.Context, result *SimulationResult, webhookURL string, auditDir string) error {
	webhookPayload := map[string]interface{}{
		"eventType":     "flow.replay.completed",
		"flowId":        result.FlowID,
		"status":        result.Status,
		"executionTime": result.ExecutionTimeMs,
		"timestamp":     time.Now().UTC().Format(time.RFC3339),
	}
	jsonPayload, _ := json.Marshal(webhookPayload)
	req, _ := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, io.NopReader(jsonPayload))
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("webhook sync failed: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 300 {
		return fmt.Errorf("webhook rejected: %d", resp.StatusCode)
	}

	auditEntry := map[string]interface{}{
		"auditId":     result.AuditID,
		"flowId":      result.FlowID,
		"status":      result.Status,
		"executionMs": result.ExecutionTimeMs,
		"nodeCount":   len(result.NodeResults),
		"timestamp":   time.Now().UTC().Format(time.RFC3339),
		"source":      "go-replayer",
	}
	auditJSON, _ := json.MarshalIndent(auditEntry, "", "  ")
	filename := fmt.Sprintf("%s/audit_%s_%d.json", auditDir, result.FlowID, time.Now().UnixNano())
	if err := os.WriteFile(filename, auditJSON, 0644); err != nil {
		return fmt.Errorf("audit write failed: %w", err)
	}
	return nil
}

func main() {
	ctx := context.Background()
	apiBase := os.Getenv("CXONE_API_BASE")
	if apiBase == "" {
		apiBase = "https://us2.nicecxone.com"
	}
	webhookURL := os.Getenv("QA_WEBHOOK_URL")
	if webhookURL == "" {
		webhookURL = "https://qa.example.com/webhooks/cxone-replay"
	}

	tm := NewTokenManager(OAuthConfig{
		BaseURL:   apiBase,
		ClientID:  os.Getenv("CXONE_CLIENT_ID"),
		ClientSec: os.Getenv("CXONE_CLIENT_SECRET"),
		GrantType: "client_credentials",
		Scope:     "flow:read flow:simulate",
	})

	payload := BuildReplayPayload(
		"flow-abc-123",
		[]string{"start", "menu-main", "dtmf-capture", "queue-verify", "end"},
		[]string{"1", "3", "2"},
	)

	result, err := ExecuteSimulation(ctx, tm, apiBase, payload)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Simulation failed: %v\n", err)
		os.Exit(1)
	}

	if err := VerifySimulationState(result, payload.Simulate.PathMatrix); err != nil {
		fmt.Fprintf(os.Stderr, "State verification failed: %v\n", err)
		os.Exit(1)
	}

	if err := SyncWebhookAndAudit(ctx, result, webhookURL, "./audit"); err != nil {
		fmt.Fprintf(os.Stderr, "Sync/audit failed: %v\n", err)
	} else {
		fmt.Printf("Replay completed successfully. Execution time: %d ms\n", result.ExecutionTimeMs)
	}
}

Common Errors & Debugging

Error: 429 Too Many Requests

• What causes it: The CXone platform enforces per-tenant rate limits on simulation endpoints. Rapid replay iteration triggers throttling.
• How to fix it: Implement exponential backoff and respect the Retry-After header if present. The provided code applies a 2^attempt second delay and retries up to three times.
• Code showing the fix: The retry loop in ExecuteSimulation handles http.StatusTooManyRequests by sleeping before the next attempt. Adjust maxRetries if your pipeline requires higher throughput.

Error: 400 Bad Request (Schema Validation)

• What causes it: The path matrix contains invalid node identifiers, or the maxNodeTraversal limit is lower than the actual path length.
• How to fix it: Run ValidateReplaySchema before submission. Ensure node IDs match exactly with the Pure Connect flow builder identifiers.
• Code showing the fix: The validation function checks path length against traversal limits and rejects empty strings. Update the PathMatrix slice to match your flow architecture.

Error: 504 Gateway Timeout (Simulation Hang)

• What causes it: The simulation engine exceeds the TimeoutThreshold due to recursive loops or slow prompt playback timing.
• How to fix it: Increase TimeoutThreshold within platform limits or reduce PromptDelayMs in the inputs. Enable EnableErrorInject to bypass blocking decision nodes during testing.
• Code showing the fix: The HTTP client timeout is set to TimeoutThreshold + 5000 milliseconds. The verification step rejects results exceeding 45 seconds. Adjust these values based on your flow complexity.

Official References

• NICE CXone Flow Simulation API Documentation
• NICE CXone OAuth 2.0 Authentication Guide
• Pure Connect Flow Builder Node Reference
• CXone Rate Limiting and Retry Policies