Validating DNC Compliance in Genesys Cloud Outbound Campaigns with a Go Microservice

What You Will Build

• This microservice receives contact batches, validates phone numbers against a Redis-backed DNC blacklist and geographic routing rules, and returns a structured blocking decision.
• The service uses the Genesys Cloud Outbound API to apply validated DNC rules and update campaign dialer configurations before activation.
• The implementation uses Go 1.21, the standard net/http library, and go-redis/redis/v9 for distributed state management.

Prerequisites

• OAuth 2.0 Client Credentials flow configured in Genesys Cloud with scopes outbound:campaign:write and outbound:contact:write
• Genesys Cloud API v2 base URL format: https://{your-domain}.mygenesys.cloud/api/v2
• Go 1.21 or later with GOPROXY configured
• Redis 6.2+ running with accessible host and port
• External dependencies: github.com/go-redis/redis/v9, github.com/google/uuid, net/http, context, encoding/json, fmt, log, time

Authentication Setup

Genesys Cloud requires a bearer token for every outbound API call. The client credentials flow exchanges a client ID and secret for a short-lived access token. The following Go function handles token acquisition, caches the result, and implements automatic refresh when the token expires.

package auth

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

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

type GenesysAuth struct {
	Domain     string
	ClientID   string
	ClientSecret string
	token      string
	expiresAt  time.Time
	mu         sync.RWMutex
	client     *http.Client
}

func NewGenesysAuth(domain, clientID, clientSecret string) *GenesysAuth {
	return &GenesysAuth{
		Domain:       domain,
		ClientID:     clientID,
		ClientSecret: clientSecret,
		client:       &http.Client{Timeout: 10 * time.Second},
	}
}

func (g *GenesysAuth) GetToken(ctx context.Context) (string, error) {
	g.mu.RLock()
	if time.Now().Before(g.expiresAt) {
		token := g.token
		g.mu.RUnlock()
		return token, nil
	}
	g.mu.RUnlock()

	g.mu.Lock()
	defer g.mu.Unlock()

	if time.Now().Before(g.expiresAt) {
		return g.token, nil
	}

	tokenURL := fmt.Sprintf("https://%s/oauth/token", g.Domain)
	payload := []byte("grant_type=client_credentials&client_id=" + g.ClientID + "&client_secret=" + g.ClientSecret)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tokenURL, nil)
	if err != nil {
		return "", fmt.Errorf("failed to create token request: %w", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.SetBasicAuth(g.ClientID, g.ClientSecret)

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

	g.token = tr.AccessToken
	g.expiresAt = time.Now().Add(time.Duration(tr.ExpiresIn-60) * time.Second)
	return tr.AccessToken, nil
}

This implementation caches the token with a sixty-second safety margin before expiration. The read-write mutex prevents concurrent token refresh calls under load. Every subsequent API call will invoke GetToken to retrieve a valid bearer token.

Implementation

Step 1: Redis DNC and Geo-Fencing Lookup

The microservice stores blocked numbers in a Redis set named dnc:blacklist and geographic routing rules in a hash named dnc:geo_rules. The lookup function checks both structures and returns a blocking decision.

package dnc

import (
	"context"
	"fmt"
	"github.com/go-redis/redis/v9"
)

type GeoRule struct {
	Allowed   bool
	RiskLevel string
}

type ValidationService struct {
	redisClient *redis.Client
}

func NewValidationService(redisAddr string, redisPass string) *ValidationService {
	rdb := redis.NewClient(&redis.Options{
		Addr:     redisAddr,
		Password: redisPass,
		DB:       0,
	})
	return &ValidationService{redisClient: rdb}
}

func (v *ValidationService) CheckNumber(ctx context.Context, phoneNumber string) (bool, string, error) {
	// Check DNC blacklist
	isBlacklisted, err := v.redisClient.SIsMember(ctx, "dnc:blacklist", phoneNumber).Result()
	if err != nil {
		return false, "", fmt.Errorf("redis blacklist check failed: %w", err)
	}
	if isBlacklisted {
		return true, "dnc_blacklist", nil
	}

	// Check geo-fencing rules
	rule, err := v.redisClient.HGet(ctx, "dnc:geo_rules", phoneNumber).Result()
	if err != nil && err != redis.Nil {
		return false, "", fmt.Errorf("redis geo rule check failed: %w", err)
	}
	if err == redis.Nil {
		// No geo rule found, default to allowed
		return false, "allowed", nil
	}

	var gr GeoRule
	if err := json.Unmarshal([]byte(rule), &gr); err != nil {
		return false, "", fmt.Errorf("failed to parse geo rule: %w", err)
	}

	if !gr.Allowed {
		return true, fmt.Sprintf("geo_blocked_%s", gr.RiskLevel), nil
	}

	return false, "allowed", nil
}

The SIsMember command provides O(1) lookup for the blacklist. The HGet command retrieves geographic restrictions tied to area codes or country prefixes. The function returns a boolean indicating whether the number is blocked, a reason string, and an error if Redis fails.

Step 2: Contact Validation Endpoint

The HTTP handler receives a batch of contacts, runs each number through the Redis lookup, and aggregates the results. The endpoint expects a JSON array of contact objects and returns a structured validation report.

package handler

import (
	"encoding/json"
	"net/http"
	"context"
	"time"
	"dnc-service/dnc"
	"dnc-service/auth"
)

type ContactRequest struct {
	PhoneNumber string `json:"phoneNumber"`
	CampaignID  string `json:"campaignId"`
}

type ContactDecision struct {
	PhoneNumber string `json:"phoneNumber"`
	Blocked     bool   `json:"blocked"`
	Reason      string `json:"reason"`
}

type ValidationReport struct {
	Total     int               `json:"total"`
	Blocked   int               `json:"blocked"`
	Allowed   int               `json:"allowed"`
	Decisions []ContactDecision `json:"decisions"`
}

type Service struct {
	auth    *auth.GenesysAuth
	dnc     *dnc.ValidationService
	httpCli *http.Client
}

func NewService(a *auth.GenesysAuth, d *dnc.ValidationService) *Service {
	return &Service{
		auth:    a,
		dnc:     d,
		httpCli: &http.Client{Timeout: 15 * time.Second},
	}
}

func (s *Service) ValidateContacts(w http.ResponseWriter, r *http.Request) {
	ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
	defer cancel()

	var contacts []ContactRequest
	if err := json.NewDecoder(r.Body).Decode(&contacts); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}

	report := ValidationReport{Total: len(contacts)}
	for _, c := range contacts {
		blocked, reason, err := s.dnc.CheckNumber(ctx, c.PhoneNumber)
		if err != nil {
			http.Error(w, fmt.Sprintf("validation error for %s: %v", c.PhoneNumber, err), http.StatusInternalServerError)
			return
		}
		decision := ContactDecision{
			PhoneNumber: c.PhoneNumber,
			Blocked:     blocked,
			Reason:      reason,
		}
		report.Decisions = append(report.Decisions, decision)
		if blocked {
			report.Blocked++
		} else {
			report.Allowed++
		}
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(report)
}

The handler enforces a five-second context deadline to prevent Redis latency from blocking the HTTP thread. Each contact is evaluated independently. The response structure allows the upstream data pipeline to filter blocked numbers before importing them into Genesys Cloud.

Step 3: Genesys Cloud Campaign Rule Injection

After validation, the service updates the Genesys Cloud campaign configuration to enforce DNC blocking at the dialer level. The API call modifies the campaign’s dialerConfiguration and attaches a contact list containing only allowed numbers.

Required OAuth scope: outbound:campaign:write

package genesys

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"dnc-service/auth"
)

type DialerConfigUpdate struct {
	ContactListID string `json:"contactListId"`
	DNCOptOut     bool   `json:"dncOptOut"`
	BlockedNumbers []string `json:"blockedNumbers"`
}

func ApplyCampaignRules(ctx context.Context, auth *auth.GenesysAuth, campaignID string, config DialerConfigUpdate) error {
	token, err := auth.GetToken(ctx)
	if err != nil {
		return fmt.Errorf("token retrieval failed: %w", err)
	}

	url := fmt.Sprintf("https://%s/api/v2/outbound/campaigns/%s", auth.Domain, campaignID)
	payload, err := json.Marshal(config)
	if err != nil {
		return fmt.Errorf("failed to marshal payload: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPut, url, bytes.NewReader(payload))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("campaign update request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusForbidden {
		return fmt.Errorf("403 Forbidden: missing outbound:campaign:write scope")
	}
	if resp.StatusCode == http.StatusTooManyRequests {
		return fmt.Errorf("429 Too Many Requests: rate limit exceeded")
	}
	if resp.StatusCode >= 500 {
		return fmt.Errorf("5xx server error: status %d", resp.StatusCode)
	}
	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
		return fmt.Errorf("unexpected status: %d", resp.StatusCode)
	}

	return nil
}

The PUT /api/v2/outbound/campaigns/{campaignId} endpoint accepts a partial campaign object. The dncOptOut flag instructs the Genesys Cloud dialer to skip numbers flagged in the platform’s internal DNC registry. The blockedNumbers array provides an explicit override for campaign-specific restrictions.

Step 4: Retry and Rate Limit Handling

Genesys Cloud enforces strict rate limits on outbound endpoints. The following wrapper implements exponential backoff with jitter for 429 responses.

package retry

import (
	"context"
	"math/rand"
	"time"
)

func RetryWithBackoff(ctx context.Context, maxRetries int, operation func() error) error {
	var err error
	for i := 0; i < maxRetries; i++ {
		err = operation()
		if err == nil {
			return nil
		}

		// Check for 429 or 5xx errors to trigger retry
		if !isRetryable(err) {
			return err
		}

		backoff := time.Duration(1<<uint(i)) * time.Second
		jitter := time.Duration(rand.Intn(500)) * time.Millisecond
		time.Sleep(backoff + jitter)
	}
	return fmt.Errorf("max retries exceeded: %w", err)
}

func isRetryable(err error) bool {
	// In production, parse the error string or use a custom error type
	// to check for 429 or 5xx status codes
	return true
}

This retry logic prevents cascade failures during high-throughput contact imports. The jitter prevents thundering herd problems when multiple microservice instances retry simultaneously.

Complete Working Example

The following module combines authentication, Redis validation, HTTP routing, and Genesys Cloud API integration into a single runnable service.

package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"time"

	"dnc-service/auth"
	"dnc-service/dnc"
	"dnc-service/handler"
	"dnc-service/genesys"
	"dnc-service/retry"
)

type App struct {
	service *handler.Service
}

func main() {
	domain := "myorg.mygenesys.cloud"
	clientID := "your_client_id"
	clientSecret := "your_client_secret"
	redisAddr := "localhost:6379"
	redisPass := ""

	authClient := auth.NewGenesysAuth(domain, clientID, clientSecret)
	dncClient := dnc.NewValidationService(redisAddr, redisPass)
	svc := handler.NewService(authClient, dncClient)

	app := &App{service: svc}

	http.HandleFunc("/validate", app.handleValidation)
	http.HandleFunc("/apply-campaign-rules", app.handleCampaignUpdate)

	log.Println("DNC validation service listening on :8080")
	if err := http.ListenAndServe(":8080", nil); err != nil {
		log.Fatalf("Server failed: %v", err)
	}
}

func (a *App) handleValidation(w http.ResponseWriter, r *http.Request) {
	a.service.ValidateContacts(w, r)
}

func (a *App) handleCampaignUpdate(w http.ResponseWriter, r *http.Request) {
	ctx, cancel := context.WithTimeout(r.Context(), 15*time.Second)
	defer cancel()

	var req struct {
		CampaignID string `json:"campaignId"`
		ContactListID string `json:"contactListId"`
		BlockedNumbers []string `json:"blockedNumbers"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid payload", http.StatusBadRequest)
		return
	}

	config := genesys.DialerConfigUpdate{
		ContactListID:  req.ContactListID,
		DNCOptOut:      true,
		BlockedNumbers: req.BlockedNumbers,
	}

	err := retry.RetryWithBackoff(ctx, 3, func() error {
		return genesys.ApplyCampaignRules(ctx, a.service.Auth(), req.CampaignID, config)
	})
	if err != nil {
		http.Error(w, fmt.Sprintf("campaign update failed: %v", err), http.StatusBadGateway)
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(map[string]string{"status": "applied"})
}

This server exposes two endpoints. The /validate endpoint processes contact batches against Redis. The /apply-campaign-rules endpoint pushes the filtered DNC configuration to Genesys Cloud with automatic retry logic. Replace the placeholder credentials and Redis connection string before deployment.

Common Errors and Debugging

Error: 401 Unauthorized

• Cause: Expired OAuth token or missing Authorization header.
• Fix: Verify the client credentials flow returns a valid token. Ensure the GetToken function executes before every API call. Check that the token string is prefixed with Bearer .
• Code fix: The authentication module already implements automatic refresh. If 401 persists, verify the OAuth client has outbound:campaign:write and outbound:contact:write scopes assigned in the Genesys Cloud admin console.

Error: 429 Too Many Requests

• Cause: Exceeding Genesys Cloud rate limits on outbound endpoints. The platform enforces per-client and per-tenant quotas.
• Fix: Implement exponential backoff with jitter. The RetryWithBackoff function handles this automatically. Monitor the Retry-After header in the response body and adjust sleep intervals accordingly.
• Code fix: Parse the Retry-After header if present and override the default backoff calculation.

Error: 400 Bad Request

• Cause: Malformed JSON payload or invalid campaign ID format. Genesys Cloud validates campaign UUIDs strictly.
• Fix: Ensure the campaignId parameter matches the UUID format returned by GET /api/v2/outbound/campaigns. Validate the blockedNumbers array contains properly formatted E.164 numbers.
• Code fix: Add schema validation using github.com/go-playground/validator before sending the request.

Error: Redis Timeout or Connection Refused

• Cause: Network partition, Redis server overload, or incorrect address/port configuration.
• Fix: Verify Redis connectivity using redis-cli ping. Increase the go-redis context timeout if the dataset is large. Implement circuit breaker logic for Redis calls to prevent HTTP thread exhaustion.
• Code fix: Wrap CheckNumber with a context deadline of two seconds. Return a fallback decision if Redis fails, and log the incident for operational review.

Official References

• Genesys Cloud Outbound Campaigns API
• Genesys Cloud OAuth 2.0 Client Credentials
• Genesys Cloud Outbound Contacts API
• go-redis/v9 Documentation
• Genesys Cloud Rate Limiting Guidelines