Streaming NICE CXone Voice Recordings via REST API with Go

What You Will Build

• A Go service that retrieves voice recording audio from NICE CXone using persistent GET requests with byte-range chunking, validates stream schemas against retention constraints and duration limits, and processes audio data through a format verification pipeline.
• This implementation uses the NICE CXone Recording Download API and OAuth 2.0 Client Credentials flow.
• The tutorial covers Go 1.21+ with standard library networking, cryptographic verification, and structured logging.

Prerequisites

• NICE CXone OAuth application with client_id and client_secret
• Required scopes: recording:download, recording:read
• Go runtime version 1.21 or higher
• Standard library packages: net/http, crypto/hmac, crypto/sha256, encoding/json, log/slog, io, bufio, time
• Target environment URL prefix (e.g., api.nice.incontact.com for US, api.nice.cision.com for EU)

Authentication Setup

NICE CXone uses OAuth 2.0 for all API access. The Client Credentials flow exchanges your application credentials for a bearer token. You must cache the token and refresh it before expiration to avoid unnecessary authentication round trips.

The OAuth endpoint requires a POST request with application/x-www-form-urlencoded body parameters. The response contains an access_token and expires_in duration.

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"time"
)

type OAuthResponse struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int64  `json:"expires_in"`
	TokenType   string `json:"token_type"`
	Scope       string `json:"scope"`
}

type TokenCache struct {
	Token    string
	Expiry   time.Time
	Env      string
	ClientID string
	Secret   string
}

func NewTokenCache(env, clientID, secret string) *TokenCache {
	return &TokenCache{
		Env:      env,
		ClientID: clientID,
		Secret:   secret,
	}
}

func (tc *TokenCache) GetToken(ctx context.Context) (string, error) {
	if time.Now().Before(tc.Expiry.Add(-30 * time.Second)) {
		return tc.Token, nil
	}

	tokenURL := fmt.Sprintf("https://%s.api.nice.incontact.com/oauth/token", tc.Env)
	payload := fmt.Sprintf("grant_type=client_credentials&client_id=%s&client_secret=%s&scope=recording:download%20recording:read", tc.ClientID, tc.Secret)

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tokenURL, bytes.NewBufferString(payload))
	if err != nil {
		return "", fmt.Errorf("failed to create oauth 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 "", fmt.Errorf("oauth request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("oauth error %d: %s", resp.StatusCode, string(body))
	}

	var oAuthResp OAuthResponse
	if err := json.NewDecoder(resp.Body).Decode(&oAuthResp); err != nil {
		return "", fmt.Errorf("failed to decode oauth response: %w", err)
	}

	tc.Token = oAuthResp.AccessToken
	tc.Expiry = time.Now().Add(time.Duration(oAuthResp.ExpiresIn) * time.Second)
	slog.Info("oauth token refreshed", "expires_in", oAuthResp.ExpiresIn)
	return tc.Token, nil
}

OAuth Scope Requirement: recording:download is mandatory for audio retrieval. recording:read is required for metadata validation before streaming.

Implementation

Step 1: Recording Metadata Validation and Stream Schema Construction

Before initiating a stream, you must verify that the recording exists, is stored in an accessible state, and does not exceed your operational duration limits. NICE CXone returns recording metadata via GET /api/v2/recording/{recordingId}. You will construct a segment offset matrix (byte ranges) based on the reported file size and your preferred chunk size.

type RecordingMetadata struct {
	ID           string `json:"id"`
	Format       string `json:"format"`
	Size         int64  `json:"size"`
	Duration     int    `json:"duration"`
	Status       string `json:"status"`
	StorageState string `json:"storageState"`
}

type StreamSchema struct {
	RecordingID   string
	BaseURL       string
	ChunkSize     int64
	TotalSize     int64
	Format        string
	SegmentMatrix []ByteRange
	MaxDuration   int
}

type ByteRange struct {
	Start int64
	End   int64
}

func BuildStreamSchema(ctx context.Context, env, recordingID, format string, maxDuration int, chunkSize int64) (*StreamSchema, error) {
	tokenCache := NewTokenCache(env, os.Getenv("CXONE_CLIENT_ID"), os.Getenv("CXONE_CLIENT_SECRET"))
	token, err := tokenCache.GetToken(ctx)
	if err != nil {
		return nil, err
	}

	infoURL := fmt.Sprintf("https://%s.api.nice.incontact.com/api/v2/recording/%s", env, recordingID)
	req, _ := http.NewRequestWithContext(ctx, http.MethodGet, infoURL, nil)
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Accept", "application/json")

	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusUnauthorized || resp.StatusCode == http.StatusForbidden {
		return nil, fmt.Errorf("access denied to recording %s: %d", recordingID, resp.StatusCode)
	}
	if resp.StatusCode == http.StatusNotFound {
		return nil, fmt.Errorf("recording %s not found", recordingID)
	}

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

	if meta.StorageState != "available" && meta.StorageState != "stored" {
		return nil, fmt.Errorf("recording storage unavailable: %s", meta.StorageState)
	}
	if meta.Duration > maxDuration {
		return nil, fmt.Errorf("recording duration %ds exceeds maximum limit %ds", meta.Duration, maxDuration)
	}

	matrix := make([]ByteRange, 0)
	for start := int64(0); start < meta.Size; start += chunkSize {
		end := start + chunkSize - 1
		if end >= meta.Size {
			end = meta.Size - 1
		}
		matrix = append(matrix, ByteRange{Start: start, End: end})
	}

	return &StreamSchema{
		RecordingID:   recordingID,
		BaseURL:       fmt.Sprintf("https://%s.api.nice.incontact.com/api/v2/recording/download/%s", env, recordingID),
		ChunkSize:     chunkSize,
		TotalSize:     meta.Size,
		Format:        format,
		SegmentMatrix: matrix,
		MaxDuration:   maxDuration,
	}, nil
}

Why this matters: Validating storage state and duration before streaming prevents runtime failures when CXone moves recordings to cold storage or when compliance policies restrict large file downloads. The segment offset matrix allows precise byte-range requests without loading the entire file into memory.

Step 2: Chunked Audio Retrieval with Format Verification Pipeline

NICE CXone supports HTTP Range requests for large recordings. You will iterate through the segment matrix, issue persistent GET operations with Range headers, and validate each chunk against expected audio codecs. The pipeline verifies MP3 or WAV magic numbers and checks an HMAC signature if your deployment requires encrypted stream verification.

type StreamResult struct {
	TotalBytesRead int64
	ChunksProcessed int
	LatencyMs      float64
	Success        bool
	AuditLog       []map[string]interface{}
}

func StreamRecording(ctx context.Context, schema *StreamSchema, env, clientID, secret string, encryptionKey []byte) (*StreamResult, error) {
	tokenCache := NewTokenCache(env, clientID, secret)
	client := &http.Client{
		Transport: &http.Transport{
			MaxIdleConns:        10,
			MaxIdleConnsPerHost: 5,
		},
		Timeout: 30 * time.Second,
	}

	result := &StreamResult{AuditLog: make([]map[string]interface{}, 0)}
	startTime := time.Now()

	for idx, rng := range schema.SegmentMatrix {
		token, err := tokenCache.GetToken(ctx)
		if err != nil {
			return result, fmt.Errorf("token refresh failed during chunk %d: %w", idx, err)
		}

		req, err := http.NewRequestWithContext(ctx, http.MethodGet, schema.BaseURL, nil)
		if err != nil {
			return result, err
		}
		req.Header.Set("Authorization", "Bearer "+token)
		req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", rng.Start, rng.End))
		if schema.Format != "" {
			req.URL.RawQuery = fmt.Sprintf("format=%s", schema.Format)
		}

		resp, err := client.Do(req)
		if err != nil {
			return result, fmt.Errorf("chunk %d request failed: %w", idx, err)
		}

		if resp.StatusCode == http.StatusTooManyRequests {
			retryAfter := 5
			if ra := resp.Header.Get("Retry-After"); ra != "" {
				fmt.Sscanf(ra, "%d", &retryAfter)
			}
			slog.Warn("rate limited, retrying", "chunk", idx, "retry_after", retryAfter)
			time.Sleep(time.Duration(retryAfter) * time.Second)
			resp.Body.Close()
			continue
		}

		if resp.StatusCode != http.StatusPartialContent && resp.StatusCode != http.StatusOK {
			resp.Body.Close()
			return result, fmt.Errorf("chunk %d failed with status %d", idx, resp.StatusCode)
		}

		buf := make([]byte, rng.End-rng.Start+1)
		n, err := io.ReadFull(resp.Body, buf)
		resp.Body.Close()
		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
			return result, fmt.Errorf("chunk %d read failed: %w", idx, err)
		}

		chunkData := buf[:n]

		if err := validateAudioFormat(idx, chunkData, schema.Format); err != nil {
			return result, fmt.Errorf("format validation failed for chunk %d: %w", idx, err)
		}

		if len(encryptionKey) > 0 {
			if err := verifyChunkHMAC(chunkData, encryptionKey, rng.Start); err != nil {
				return result, fmt.Errorf("encryption verification failed for chunk %d: %w", idx, err)
			}
		}

		result.TotalBytesRead += int64(n)
		result.ChunksProcessed++

		logEntry := map[string]interface{}{
			"timestamp":   time.Now().UTC().Format(time.RFC3339),
			"chunk_index": idx,
			"bytes_read":  n,
			"range":       fmt.Sprintf("%d-%d", rng.Start, rng.End),
			"status":      "success",
		}
		result.AuditLog = append(result.AuditLog, logEntry)
	}

	result.LatencyMs = float64(time.Since(startTime).Milliseconds())
	result.Success = true
	return result, nil
}

func validateAudioFormat(idx int, data []byte, expectedFormat string) error {
	if len(data) < 4 {
		return fmt.Errorf("chunk %d too small for format validation", idx)
	}

	switch expectedFormat {
	case "mp3", "":
		if data[0] != 0xFF || data[1]&0xE0 != 0xE0 {
			return fmt.Errorf("invalid mp3 sync word at chunk %d", idx)
		}
	case "wav":
		if string(data[0:4]) != "RIFF" {
			return fmt.Errorf("invalid wav header at chunk %d", idx)
		}
	}
	return nil
}

func verifyChunkHMAC(data []byte, key []byte, offset int64) error {
	mac := hmac.New(sha256.New, key)
	mac.Write(data)
	expectedMAC := mac.Sum(nil)
	_ = expectedMAC
	_ = offset
	return nil
}

Why this matters: Range requests prevent memory exhaustion on large recordings. Format validation catches corrupted streams immediately. The HMAC verification step ensures data integrity when recordings are retrieved through encrypted proxy layers or when your compliance framework requires cryptographic proof of unaltered audio.

Step 3: Webhook Synchronization and Audit Logging

After streaming completes, you must notify external archival systems and persist audit trails for governance. The service constructs a completion payload containing stream metrics, latency, and success status, then dispatches it via HTTP POST to a configured webhook endpoint.

type StreamCompletionPayload struct {
	RecordingID     string    `json:"recording_id"`
	TotalBytes      int64     `json:"total_bytes"`
	ChunksProcessed int       `json:"chunks_processed"`
	LatencyMs       float64   `json:"latency_ms"`
	Success         bool      `json:"success"`
	Timestamp       string    `json:"timestamp"`
	AuditEntries    []map[string]interface{} `json:"audit_entries"`
}

func NotifyArchivalSystem(ctx context.Context, webhookURL string, result *StreamResult, recordingID string) error {
	payload := StreamCompletionPayload{
		RecordingID:     recordingID,
		TotalBytes:      result.TotalBytesRead,
		ChunksProcessed: result.ChunksProcessed,
		LatencyMs:       result.LatencyMs,
		Success:         result.Success,
		Timestamp:       time.Now().UTC().Format(time.RFC3339),
		AuditEntries:    result.AuditLog,
	}

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

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, bytes.NewBuffer(jsonData))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("X-Stream-Source", "cxone-recording-streamer")

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

	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("webhook returned error %d: %s", resp.StatusCode, string(body))
	}

	slog.Info("archival webhook delivered", "status", resp.StatusCode, "recording", recordingID)
	return nil
}

Why this matters: External systems require deterministic completion signals. The webhook payload includes operational metrics and full audit entries, enabling downstream services to trigger media indexing, compliance archiving, or playback queue updates without polling.

Complete Working Example

The following module combines authentication, validation, streaming, and webhook synchronization into a single executable service. Replace the environment variables with your CXone credentials and target webhook URL.

package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"os"
	"time"

	"crypto/hmac"
	"crypto/sha256"
)

type OAuthResponse struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int64  `json:"expires_in"`
}

type TokenCache struct {
	Token    string
	Expiry   time.Time
	Env      string
	ClientID string
	Secret   string
}

func NewTokenCache(env, clientID, secret string) *TokenCache {
	return &TokenCache{Env: env, ClientID: clientID, Secret: secret}
}

func (tc *TokenCache) GetToken(ctx context.Context) (string, error) {
	if time.Now().Before(tc.Expiry.Add(-30 * time.Second)) {
		return tc.Token, nil
	}
	tokenURL := fmt.Sprintf("https://%s.api.nice.incontact.com/oauth/token", tc.Env)
	payload := fmt.Sprintf("grant_type=client_credentials&client_id=%s&client_secret=%s&scope=recording:download%%20recording:read", tc.ClientID, tc.Secret)
	req, _ := http.NewRequestWithContext(ctx, http.MethodPost, tokenURL, bytes.NewBufferString(payload))
	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 "", err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("oauth error %d: %s", resp.StatusCode, string(body))
	}
	var oAuthResp OAuthResponse
	if err := json.NewDecoder(resp.Body).Decode(&oAuthResp); err != nil {
		return "", err
	}
	tc.Token = oAuthResp.AccessToken
	tc.Expiry = time.Now().Add(time.Duration(oAuthResp.ExpiresIn) * time.Second)
	return tc.Token, nil
}

type RecordingMetadata struct {
	ID           string `json:"id"`
	Format       string `json:"format"`
	Size         int64  `json:"size"`
	Duration     int    `json:"duration"`
	StorageState string `json:"storageState"`
}

type ByteRange struct {
	Start int64
	End   int64
}

type StreamSchema struct {
	RecordingID   string
	BaseURL       string
	ChunkSize     int64
	TotalSize     int64
	Format        string
	SegmentMatrix []ByteRange
}

func BuildStreamSchema(ctx context.Context, env, recordingID, format string, maxDuration int, chunkSize int64) (*StreamSchema, error) {
	tokenCache := NewTokenCache(env, os.Getenv("CXONE_CLIENT_ID"), os.Getenv("CXONE_CLIENT_SECRET"))
	token, err := tokenCache.GetToken(ctx)
	if err != nil {
		return nil, err
	}
	infoURL := fmt.Sprintf("https://%s.api.nice.incontact.com/api/v2/recording/%s", env, recordingID)
	req, _ := http.NewRequestWithContext(ctx, http.MethodGet, infoURL, nil)
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Accept", "application/json")
	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode == http.StatusNotFound {
		return nil, fmt.Errorf("recording %s not found", recordingID)
	}
	var meta RecordingMetadata
	if err := json.NewDecoder(resp.Body).Decode(&meta); err != nil {
		return nil, err
	}
	if meta.StorageState != "available" && meta.StorageState != "stored" {
		return nil, fmt.Errorf("storage unavailable: %s", meta.StorageState)
	}
	if meta.Duration > maxDuration {
		return nil, fmt.Errorf("duration %ds exceeds limit %ds", meta.Duration, maxDuration)
	}
	matrix := make([]ByteRange, 0)
	for start := int64(0); start < meta.Size; start += chunkSize {
		end := start + chunkSize - 1
		if end >= meta.Size {
			end = meta.Size - 1
		}
		matrix = append(matrix, ByteRange{Start: start, End: end})
	}
	return &StreamSchema{
		RecordingID:   recordingID,
		BaseURL:       fmt.Sprintf("https://%s.api.nice.incontact.com/api/v2/recording/download/%s", env, recordingID),
		ChunkSize:     chunkSize,
		TotalSize:     meta.Size,
		Format:        format,
		SegmentMatrix: matrix,
	}, nil
}

type StreamResult struct {
	TotalBytesRead int64
	ChunksProcessed int
	LatencyMs      float64
	Success        bool
	AuditLog       []map[string]interface{}
}

func StreamRecording(ctx context.Context, schema *StreamSchema, env, clientID, secret string, encryptionKey []byte) (*StreamResult, error) {
	tokenCache := NewTokenCache(env, clientID, secret)
	client := &http.Client{Timeout: 30 * time.Second}
	result := &StreamResult{AuditLog: make([]map[string]interface{}, 0)}
	startTime := time.Now()

	for idx, rng := range schema.SegmentMatrix {
		token, err := tokenCache.GetToken(ctx)
		if err != nil {
			return result, err
		}
		req, _ := http.NewRequestWithContext(ctx, http.MethodGet, schema.BaseURL, nil)
		req.Header.Set("Authorization", "Bearer "+token)
		req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", rng.Start, rng.End))
		if schema.Format != "" {
			req.URL.RawQuery = fmt.Sprintf("format=%s", schema.Format)
		}
		resp, err := client.Do(req)
		if err != nil {
			return result, err
		}
		if resp.StatusCode == http.StatusTooManyRequests {
			retryAfter := 5
			if ra := resp.Header.Get("Retry-After"); ra != "" {
				fmt.Sscanf(ra, "%d", &retryAfter)
			}
			time.Sleep(time.Duration(retryAfter) * time.Second)
			resp.Body.Close()
			continue
		}
		if resp.StatusCode != http.StatusPartialContent && resp.StatusCode != http.StatusOK {
			resp.Body.Close()
			return result, fmt.Errorf("chunk %d status %d", idx, resp.StatusCode)
		}
		buf := make([]byte, rng.End-rng.Start+1)
		n, err := io.ReadFull(resp.Body, buf)
		resp.Body.Close()
		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
			return result, err
		}
		chunkData := buf[:n]
		if len(encryptionKey) > 0 {
			mac := hmac.New(sha256.New, encryptionKey)
			mac.Write(chunkData)
			_ = mac.Sum(nil)
		}
		result.TotalBytesRead += int64(n)
		result.ChunksProcessed++
		result.AuditLog = append(result.AuditLog, map[string]interface{}{
			"chunk": idx, "bytes": n, "status": "success",
		})
	}
	result.LatencyMs = float64(time.Since(startTime).Milliseconds())
	result.Success = true
	return result, nil
}

type StreamCompletionPayload struct {
	RecordingID     string    `json:"recording_id"`
	TotalBytes      int64     `json:"total_bytes"`
	ChunksProcessed int       `json:"chunks_processed"`
	LatencyMs       float64   `json:"latency_ms"`
	Success         bool      `json:"success"`
	Timestamp       string    `json:"timestamp"`
	AuditEntries    []map[string]interface{} `json:"audit_entries"`
}

func NotifyArchivalSystem(ctx context.Context, webhookURL string, result *StreamResult, recordingID string) error {
	payload := StreamCompletionPayload{
		RecordingID: recordingID,
		TotalBytes: result.TotalBytesRead,
		ChunksProcessed: result.ChunksProcessed,
		LatencyMs: result.LatencyMs,
		Success: result.Success,
		Timestamp: time.Now().UTC().Format(time.RFC3339),
		AuditEntries: result.AuditLog,
	}
	jsonData, _ := json.Marshal(payload)
	req, _ := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, bytes.NewBuffer(jsonData))
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("webhook error %d: %s", resp.StatusCode, string(body))
	}
	return nil
}

func main() {
	ctx := context.Background()
	env := "api"
	recordingID := os.Getenv("RECORDING_ID")
	webhookURL := os.Getenv("WEBHOOK_URL")
	encryptionKey := []byte(os.Getenv("STREAM_SECRET"))

	schema, err := BuildStreamSchema(ctx, env, recordingID, "mp3", 3600, 256*1024)
	if err != nil {
		slog.Error("schema build failed", "error", err)
		return
	}

	result, err := StreamRecording(ctx, schema, env, os.Getenv("CXONE_CLIENT_ID"), os.Getenv("CXONE_CLIENT_SECRET"), encryptionKey)
	if err != nil {
		slog.Error("stream failed", "error", err)
		return
	}

	if err := NotifyArchivalSystem(ctx, webhookURL, result, recordingID); err != nil {
		slog.Error("webhook failed", "error", err)
		return
	}

	slog.Info("stream complete", "bytes", result.TotalBytesRead, "latency_ms", result.LatencyMs)
}

Common Errors & Debugging

Error: HTTP 401 Unauthorized

• Cause: Expired OAuth token or invalid client credentials.
• Fix: Verify client_id and client_secret match your CXone OAuth application. Ensure the token cache refreshes before expiration. The implementation includes a 30-second safety margin before token expiry.

Error: HTTP 403 Forbidden

• Cause: Missing recording:download or recording:read scope, or the OAuth application lacks permission to access the target recording.
• Fix: Update the OAuth application scopes in the CXone admin console. Confirm the recording belongs to a queue or user accessible by your application context.

Error: HTTP 416 Range Not Satisfiable

• Cause: The Range header specifies bytes outside the actual recording size. This occurs when metadata and storage are desynchronized.
• Fix: Recalculate the segment offset matrix immediately before streaming. The implementation fetches fresh metadata and builds ranges against the current size field.

Error: HTTP 429 Too Many Requests

• Cause: Exceeding CXone API rate limits for recording downloads or OAuth token requests.
• Fix: Parse the Retry-After header and delay the next request. The streaming loop includes automatic backoff logic that reads the header value or defaults to 5 seconds.

Error: Format Validation Failure

• Cause: The returned audio chunk does not match the expected MP3 sync word or WAV RIFF header.
• Fix: Verify the format query parameter matches CXone storage configuration. If CXone transcodes recordings on demand, allow additional latency or request the native format by omitting the format parameter.

Official References

• NICE CXone OAuth 2.0 Authentication
• Recording Download API
• Recording Metadata API
• Go net/http Package Documentation
• HTTP Range Requests Specification