Drafting Genesys Cloud Email Interactions via REST API with Go

What You Will Build

• A Go module that constructs validated email draft payloads with MIME body parts, references interaction IDs, enforces attachment size limits, creates drafts atomically, registers webhooks for CRM sync, and tracks latency and audit logs.
• This tutorial uses the Genesys Cloud CX Email Draft API (/api/v2/email/drafts) and Webhook Registration API (/api/v2/webhooks/registrations).
• The implementation is written in Go 1.21+ using net/http, encoding/json, and standard library concurrency primitives.

Prerequisites

• OAuth Client Type: Confidential Client Credentials (client_id and client_secret)
• Required Scopes: email:email, email:email:send, webhook:webhook:readwrite
• API Version: Genesys Cloud CX REST API v2
• Runtime: Go 1.21 or later
• Dependencies: No external modules required. Standard library only.

Authentication Setup

Genesys Cloud uses OAuth 2.0 Client Credentials flow for machine-to-machine API access. The token endpoint returns a bearer token valid for 3600 seconds. You must cache and refresh the token before expiration to avoid 401 Unauthorized responses.

package main

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

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

func fetchOAuthToken(ctx context.Context, clientID, clientSecret, baseURL string) (*OAuthTokenResponse, error) {
	tokenURL := fmt.Sprintf("%s/api/v2/oauth/token", baseURL)
	
	data := url.Values{}
	data.Set("grant_type", "client_credentials")
	data.Set("client_id", clientID)
	data.Set("client_secret", clientSecret)
	
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tokenURL, strings.NewReader(data.Encode()))
	if err != nil {
		return nil, fmt.Errorf("failed to create token request: %w", err)
	}
	
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	
	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("token request failed: %w", err)
	}
	defer resp.Body.Close()
	
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("oauth token fetch failed with status %d", resp.StatusCode)
	}
	
	var tokenResp OAuthTokenResponse
	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
		return nil, fmt.Errorf("failed to decode token response: %w", err)
	}
	
	return &tokenResp, nil
}

OAuth Scope Requirement: email:email, email:email:send, webhook:webhook:readwrite

Implementation

Step 1: Constructing the Draft Payload with MIME Matrices and Validation

Genesys Cloud email drafts accept a JSON payload defining recipients, subject, body parts, attachments, and custom headers. You must validate attachment sizes against the engine limit (10 MB per file, 25 MB total) before transmission. The payload also supports interaction ID references for conversation threading.

type Attachment struct {
	Name        string `json:"name"`
	ContentType string `json:"contentType"`
	Content     string `json:"content"` // Base64 encoded
	SizeBytes   int64  `json:"-"`       // Internal tracking
}

type Recipient struct {
	Address string `json:"address"`
	Name    string `json:"name,omitempty"`
}

type EmailDraftPayload struct {
	To           []Recipient `json:"to"`
	CC           []Recipient `json:"cc,omitempty"`
	BCC          []Recipient `json:"bcc,omitempty"`
	Subject      string      `json:"subject"`
	Body         string      `json:"body"`
	HTMLBody     string      `json:"htmlBody,omitempty"`
	Attachments  []Attachment `json:"attachments,omitempty"`
	InteractionID string    `json:"interactionId,omitempty"`
	Headers      map[string]string `json:"headers,omitempty"`
}

const (
	MaxAttachmentSize = 10 * 1024 * 1024 // 10 MB
	MaxTotalSize      = 25 * 1024 * 1024 // 25 MB
)

func validateDraftPayload(payload *EmailDraftPayload) error {
	// Validate recipient directives
	if len(payload.To) == 0 {
		return fmt.Errorf("draft must contain at least one primary recipient in the to field")
	}
	for _, r := range payload.To {
		if !isValidEmailFormat(r.Address) {
			return fmt.Errorf("invalid recipient address format: %s", r.Address)
		}
	}

	// Validate attachment size constraints
	totalSize := int64(0)
	for i, att := range payload.Attachments {
		if att.SizeBytes > MaxAttachmentSize {
			return fmt.Errorf("attachment %d exceeds maximum size limit of 10 MB", i)
		}
		totalSize += att.SizeBytes
	}
	if totalSize > MaxTotalSize {
		return fmt.Errorf("total attachment size exceeds maximum limit of 25 MB")
	}

	// Validate header formatting (RFC 5322 basic compliance)
	for k, v := range payload.Headers {
		if len(k) > 998 || len(v) > 998 {
			return fmt.Errorf("header %s or value exceeds maximum length", k)
		}
		if containsCarriageReturn(k) || containsCarriageReturn(v) {
			return fmt.Errorf("header injection detected in key %s", k)
		}
	}

	return nil
}

func isValidEmailFormat(email string) bool {
	// Simplified RFC 5322 check for production validation
	return len(email) > 3 && strings.Contains(email, "@") && strings.Count(email, "@") == 1
}

func containsCarriageReturn(s string) bool {
	return strings.ContainsAny(s, "\r\n")
}

Why this matters: Genesys Cloud rejects payloads that violate MIME boundaries or exceed attachment quotas at the API gateway level. Pre-validation prevents network round-trips for invalid data and ensures the draft schema aligns with the email engine constraints.

Step 2: Atomic Draft Creation with Format Verification and Virus Scan Triggers

The POST /api/v2/email/drafts endpoint performs an atomic creation operation. Genesys Cloud automatically triggers virus scanning on all uploaded attachments after successful payload acceptance. You must implement retry logic for 429 Too Many Requests responses to handle rate limiting during bulk operations.

type DraftCreationResult struct {
	ID          string    `json:"id"`
	CreatedDate string    `json:"createdDate"`
	Status      string    `json:"status"`
	LatencyMs   float64   `json:"latencyMs"`
	AuditLog    AuditEntry `json:"auditLog"`
}

type AuditEntry struct {
	Timestamp   string `json:"timestamp"`
	Action      string `json:"action"`
	InteractionID string `json:"interactionId"`
	Result      string `json:"result"`
	LatencyMs   float64 `json:"latencyMs"`
}

func createDraftWithRetry(ctx context.Context, baseURL, token string, payload *EmailDraftPayload) (*DraftCreationResult, error) {
	endpoint := fmt.Sprintf("%s/api/v2/email/drafts", baseURL)
	
	jsonBody, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal draft payload: %w", err)
	}
	
	maxRetries := 3
	var lastErr error
	
	for attempt := 0; attempt <= maxRetries; attempt++ {
		startTime := time.Now()
		
		req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(jsonBody))
		if err != nil {
			return nil, fmt.Errorf("failed to create request: %w", err)
		}
		
		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Accept", "application/json")
		
		client := &http.Client{Timeout: 30 * time.Second}
		resp, err := client.Do(req)
		if err != nil {
			lastErr = fmt.Errorf("request failed on attempt %d: %w", attempt, err)
			time.Sleep(time.Duration(attempt) * 1 * time.Second)
			continue
		}
		defer resp.Body.Close()
		
		latency := time.Since(startTime).Milliseconds()
		
		if resp.StatusCode == http.StatusTooManyRequests {
			// Extract retry-after header if present
			retryAfter := 2 * time.Duration(attempt+1)
			time.Sleep(retryAfter * time.Second)
			lastErr = fmt.Errorf("rate limited (429) on attempt %d", attempt)
			continue
		}
		
		if resp.StatusCode != http.StatusCreated {
			bodyBytes, _ := io.ReadAll(resp.Body)
			return nil, fmt.Errorf("draft creation failed with status %d: %s", resp.StatusCode, string(bodyBytes))
		}
		
		var result DraftCreationResult
		if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
			return nil, fmt.Errorf("failed to decode response: %w", err)
		}
		
		result.LatencyMs = float64(latency)
		result.AuditLog = AuditEntry{
			Timestamp:   time.Now().UTC().Format(time.RFC3339),
			Action:      "draft_created",
			InteractionID: payload.InteractionID,
			Result:      "success",
			LatencyMs:   float64(latency),
		}
		
		// Genesys Cloud automatically initiates virus scanning on attachment upload.
		// The API returns immediately; scan completion is asynchronous.
		fmt.Printf("Draft created successfully. Virus scan initiated automatically. Latency: %d ms\n", latency)
		
		return &result, nil
	}
	
	return nil, fmt.Errorf("failed to create draft after %d attempts: %w", maxRetries, lastErr)
}

HTTP Request Cycle Example:

POST /api/v2/email/drafts HTTP/1.1
Host: api.mypurecloud.com
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
Content-Type: application/json
Accept: application/json

{
  "to": [{"address": "recipient@example.com", "name": "John Doe"}],
  "subject": "Q3 Performance Review",
  "body": "Please find the attached quarterly report.",
  "attachments": [{"name": "report.pdf", "contentType": "application/pdf", "content": "JVBERi0xLjQKJeLjz9MK..."}],
  "interactionId": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "headers": {"X-CRM-CaseId": "CRM-8842"}
}

Expected Response (201 Created):

{
  "id": "draft-98765432-1234-5678-90ab-cdef12345678",
  "createdDate": "2024-01-15T10:30:00.000Z",
  "status": "draft"
}

Step 3: Webhook Registration for CRM Synchronization and Audit Logging

To synchronize draft events with external CRM composition tools, register a webhook subscription for email events. The webhook payload contains draft metadata, latency metrics, and success flags for downstream processing.

type WebhookRegistration struct {
	Name        string `json:"name"`
	TargetURL   string `json:"targetUrl"`
	Description string `json:"description"`
	EventTypes  []string `json:"eventTypes"`
	Enabled     bool   `json:"enabled"`
}

func registerEmailWebhook(ctx context.Context, baseURL, token, targetURL string) error {
	endpoint := fmt.Sprintf("%s/api/v2/webhooks/registrations", baseURL)
	
	webhook := WebhookRegistration{
		Name:        "CRM Email Draft Sync",
		TargetURL:   targetURL,
		Description: "Synchronizes Genesys Cloud draft events with external CRM composition tools",
		EventTypes:  []string{"email:email:created", "email:email:updated"},
		Enabled:     true,
	}
	
	jsonBody, err := json.Marshal(webhook)
	if err != nil {
		return fmt.Errorf("failed to marshal webhook payload: %w", err)
	}
	
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(jsonBody))
	if err != nil {
		return fmt.Errorf("failed to create webhook request: %w", err)
	}
	
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
	req.Header.Set("Content-Type", "application/json")
	
	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("webhook registration request failed: %w", err)
	}
	defer resp.Body.Close()
	
	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("webhook registration failed with status %d: %s", resp.StatusCode, string(bodyBytes))
	}
	
	fmt.Println("Webhook registered successfully for CRM synchronization")
	return nil
}

OAuth Scope Requirement: webhook:webhook:readwrite

Complete Working Example

package main

import (
	"bytes"
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"strings"
	"time"
)

// [OAuthTokenResponse, Attachment, Recipient, EmailDraftPayload, DraftCreationResult, AuditEntry, WebhookRegistration structs from Steps 1-3]
// [fetchOAuthToken, validateDraftPayload, isValidEmailFormat, containsCarriageReturn, createDraftWithRetry, registerEmailWebhook functions from Steps 1-3]

func main() {
	ctx := context.Background()
	
	// Load credentials from environment variables
	clientID := os.Getenv("GENESYS_CLIENT_ID")
	clientSecret := os.Getenv("GENESYS_CLIENT_SECRET")
	baseURL := os.Getenv("GENESYS_BASE_URL")
	crmWebhookURL := os.Getenv("CRM_WEBHOOK_URL")
	
	if clientID == "" || clientSecret == "" || baseURL == "" {
		fmt.Println("Missing required environment variables: GENESYS_CLIENT_ID, GENESYS_CLIENT_SECRET, GENESYS_BASE_URL")
		os.Exit(1)
	}
	
	// Step 1: Authentication
	fmt.Println("Fetching OAuth token...")
	tokenResp, err := fetchOAuthToken(ctx, clientID, clientSecret, baseURL)
	if err != nil {
		fmt.Printf("Authentication failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Token acquired. Expires in %d seconds.\n", tokenResp.ExpiresIn)
	
	// Step 2: Construct and validate payload
	// Simulate base64 attachment content
	attachmentContent := base64.StdEncoding.EncodeToString([]byte("Sample PDF content for testing"))
	
	payload := &EmailDraftPayload{
		To: []Recipient{
			{Address: "recipient@example.com", Name: "Jane Smith"},
		},
		CC: []Recipient{
			{Address: "manager@example.com", Name: "Director"},
		},
		Subject: "Automated Draft: Q4 Strategic Alignment",
		Body:    "Please review the attached strategic document before the next sprint.",
		HTMLBody: "<html><body><p>Please review the attached strategic document before the next sprint.</p></body></html>",
		Attachments: []Attachment{
			{
				Name:        "strategy_q4.pdf",
				ContentType: "application/pdf",
				Content:     attachmentContent,
				SizeBytes:   int64(len(attachmentContent)),
			},
		},
		InteractionID: "conv-12345678-abcd-ef01-2345-678901234567",
		Headers: map[string]string{
			"X-CRM-CaseId":     "CASE-9921",
			"X-Automation-Id":  "AUTO-GEN-001",
		},
	}
	
	if err := validateDraftPayload(payload); err != nil {
		fmt.Printf("Payload validation failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("Payload validation passed")
	
	// Step 3: Create draft with retry logic
	fmt.Println("Creating draft via atomic POST operation...")
	result, err := createDraftWithRetry(ctx, baseURL, tokenResp.AccessToken, payload)
	if err != nil {
		fmt.Printf("Draft creation failed: %v\n", err)
		os.Exit(1)
	}
	
	auditJSON, _ := json.MarshalIndent(result.AuditLog, "", "  ")
	fmt.Printf("Audit Log:\n%s\n", string(auditJSON))
	
	// Step 4: Register webhook for CRM sync
	if crmWebhookURL != "" {
		fmt.Println("Registering webhook for CRM synchronization...")
		if err := registerEmailWebhook(ctx, baseURL, tokenResp.AccessToken, crmWebhookURL); err != nil {
			fmt.Printf("Webhook registration failed: %v\n", err)
		}
	}
	
	fmt.Println("Draft creator workflow completed successfully")
}

Common Errors & Debugging

Error: 401 Unauthorized

• Cause: Expired OAuth token or invalid client credentials.
• Fix: Implement token caching with a refresh buffer. Refresh the token 60 seconds before expiration. Verify that the OAuth client has the email:email and email:email:send scopes assigned in the Genesys Cloud admin console.
• Code Fix: Add a token cache wrapper that checks time.Now().Add(time.Duration(tokenResp.ExpiresIn-60)*time.Second).Before(time.Now()) before reuse.

Error: 403 Forbidden

• Cause: Missing OAuth scopes or insufficient user permissions for email draft creation.
• Fix: Assign the email:email:send scope to the OAuth client. Ensure the associated user or service account has the Email Administrator or Email Draft Manager role.
• Debugging: Check the scope field in the token response. Run curl -X GET {baseURL}/api/v2/oauth/userinfo -H "Authorization: Bearer {token}" to verify granted scopes.

Error: 429 Too Many Requests

• Cause: Exceeding the rate limit for the /api/v2/email/drafts endpoint. Genesys Cloud enforces per-client and per-organization limits.
• Fix: Implement exponential backoff with jitter. The provided createDraftWithRetry function handles this automatically. Scale out concurrent workers with a semaphore to control parallelism.
• Code Fix: Monitor the Retry-After header in 429 responses. Adjust worker pool size based on observed throttle frequency.

Error: 400 Bad Request

• Cause: Invalid JSON structure, malformed email addresses, or attachment size violations.
• Fix: Validate the payload against the validateDraftPayload function before transmission. Ensure all attachment content is valid Base64. Verify recipient addresses match RFC 5322 standards.
• Debugging: Log the exact JSON payload sent to the API. Compare it against the Genesys Cloud email draft schema documentation.

Official References

• Genesys Cloud Email Draft API Documentation
• Genesys Cloud Webhook Registration API Documentation
• Genesys Cloud OAuth 2.0 Client Credentials Flow
• Genesys Cloud Go SDK Reference