Recording NICE CXone Outbound Campaign Compliance Disclaimers via API with C#

What You Will Build

• The code constructs, validates, and uploads compliance disclaimer recordings to NICE CXone outbound campaigns while enforcing media engine constraints and generating audit trails.
• This tutorial uses the NICE CXone Media Recordings, Outbound Disclaimers, and Webhook Management REST APIs.
• The implementation is written in C# using HttpClient, System.Text.Json, and standard cryptographic libraries.

Prerequisites

• OAuth client type: Machine-to-Machine (Client Credentials)
• Required scopes: recordings:read, recordings:write, campaigns:read, campaigns:write, webhooks:write
• SDK/API version: CXone REST API v2
• Language/runtime: .NET 8.0 or later
• External dependencies: System.Text.Json, System.Net.Http, System.Security.Cryptography, Microsoft.Extensions.Logging.Abstractions

Authentication Setup

NICE CXone uses OAuth 2.0 Client Credentials flow for server-to-server API access. You must request a token from the regional authorization endpoint and attach it to every subsequent request. The following code demonstrates token acquisition, caching, and automatic refresh logic.

using System.Net.Http.Headers;
using System.Text.Json;
using System.Text.Json.Serialization;

public class CxoneAuthClient
{
    private readonly HttpClient _httpClient;
    private readonly string _baseUrl;
    private readonly string _clientId;
    private readonly string _clientSecret;
    private string? _cachedToken;
    private DateTime _tokenExpiry;

    public CxoneAuthClient(string baseUrl, string clientId, string clientSecret)
    {
        _baseUrl = baseUrl.TrimEnd('/');
        _clientId = clientId;
        _clientSecret = clientSecret;
        _httpClient = new HttpClient();
        _tokenExpiry = DateTime.MinValue;
    }

    public async Task<string> GetAccessTokenAsync()
    {
        if (_cachedToken != null && DateTime.UtcNow < _tokenExpiry.AddMinutes(-5))
        {
            return _cachedToken;
        }

        var tokenRequest = new FormUrlEncodedContent(new[]
        {
            new KeyValuePair<string, string>("grant_type", "client_credentials"),
            new KeyValuePair<string, string>("client_id", _clientId),
            new KeyValuePair<string, string>("client_secret", _clientSecret)
        });

        var response = await _httpClient.PostAsync($"{_baseUrl}/oauth/token", tokenRequest);

        if (!response.IsSuccessStatusCode)
        {
            var errorBody = await response.Content.ReadAsStringAsync();
            throw new HttpRequestException($"OAuth token request failed with {response.StatusCode}: {errorBody}");
        }

        var json = await response.Content.ReadAsStringAsync();
        var tokenResponse = JsonSerializer.Deserialize<OAuthTokenResponse>(json);
        _cachedToken = tokenResponse.AccessToken;
        _tokenExpiry = DateTime.UtcNow.AddSeconds(tokenResponse.ExpiresIn);

        return _cachedToken;
    }

    public async Task<HttpClient> CreateAuthenticatedClientAsync()
    {
        var token = await GetAccessTokenAsync();
        var client = new HttpClient
        {
            BaseAddress = new Uri(_baseUrl),
            Timeout = TimeSpan.FromSeconds(30)
        };
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        return client;
    }
}

public record OAuthTokenResponse(
    [property: JsonPropertyName("access_token")] string AccessToken,
    [property: JsonPropertyName("expires_in")] int ExpiresIn,
    [property: JsonPropertyName("token_type")] string TokenType);

Implementation

Step 1: Construct Recording Payloads with Disclaimer References and Capture Directives

NICE CXone requires explicit capture directives and audio matrix definitions when associating recordings with outbound disclaimers. The payload must reference the disclaimer identifier, define the audio channel matrix, and specify how the media engine should process the capture.

using System.Text.Json;
using System.Text.Json.Serialization;

public record DisclaimerRecordingPayload(
    [property: JsonPropertyName("disclaimerId")] string DisclaimerId,
    [property: JsonPropertyName("campaignId")] string CampaignId,
    [property: JsonPropertyName("captureDirective")] CaptureDirective CaptureDirective,
    [property: JsonPropertyName("audioMatrix")] AudioMatrix AudioMatrix);

public record CaptureDirective(
    [property: JsonPropertyName("type")] string Type,
    [property: JsonPropertyName("trigger")] string Trigger,
    [property: JsonPropertyName("postProcessing")] bool PostProcessing);

public record AudioMatrix(
    [property: JsonPropertyName("channels")] int Channels,
    [property: JsonPropertyName("sampleRateHz")] int SampleRateHz,
    [property: JsonPropertyName("bitDepth")] int BitDepth,
    [property: JsonPropertyName("encoding")] string Encoding);

public static class PayloadFactory
{
    public static DisclaimerRecordingPayload Create(string disclaimerId, string campaignId)
    {
        return new DisclaimerRecordingPayload(
            DisclaimerId: disclaimerId,
            CampaignId: campaignId,
            CaptureDirective: new CaptureDirective(
                Type: "compliance_disclaimer",
                Trigger: "call_connected",
                PostProcessing: true),
            AudioMatrix: new AudioMatrix(
                Channels: 1,
                SampleRateHz: 8000,
                BitDepth: 16,
                Encoding: "PCM_SIGNED"));
    }
}

Required OAuth scopes for this payload construction and subsequent submission: recordings:write, campaigns:write.

Step 2: Validate Audio Matrix Against Media Engine Constraints and Sample Rate Limits

The CXone media engine enforces strict constraints on outbound audio. Narrowband telephony requires 8000 Hz maximum sample rate. Wideband support is limited to specific campaigns. The validation pipeline checks sample rate, bit depth, channel count, and WAV header integrity before transmission.

using System.IO;
using System.Linq;

public static class AudioValidator
{
    private const int MaxSampleRate = 8000;
    private const int MaxChannels = 1;
    private const int RequiredBitDepth = 16;

    public static void ValidateAudioMatrix(AudioMatrix matrix)
    {
        if (matrix.SampleRateHz > MaxSampleRate)
        {
            throw new ArgumentException($"Sample rate {matrix.SampleRateHz} exceeds CXone media engine limit of {MaxSampleRate} Hz.");
        }

        if (matrix.Channels > MaxChannels)
        {
            throw new ArgumentException($"Channel count {matrix.Channels} exceeds outbound mono constraint.");
        }

        if (matrix.BitDepth != RequiredBitDepth)
        {
            throw new ArgumentException($"Bit depth must be {RequiredBitDepth}. Received {matrix.BitDepth}.");
        }
    }

    public static void ValidateWavHeader(byte[] wavData)
    {
        if (wavData.Length < 44)
        {
            throw new InvalidDataException("WAV file is too small to contain a valid header.");
        }

        var riffHeader = System.Text.Encoding.ASCII.GetString(wavData[0..4]);
        var waveHeader = System.Text.Encoding.ASCII.GetString(wavData[8..12]);
        var fmtHeader = System.Text.Encoding.ASCII.GetString(wavData[12..16]);

        if (riffHeader != "RIFF" || waveHeader != "WAVE" || fmtHeader != "fmt ")
        {
            throw new InvalidDataException("Invalid WAV header structure. Expected RIFF/WAVE/fmt chunks.");
        }

        var channels = BitConverter.ToInt16(wavData, 22);
        var sampleRate = BitConverter.ToInt32(wavData, 24);
        var bitDepth = BitConverter.ToInt16(wavData, 34);

        if (channels != 1 || sampleRate > MaxSampleRate || bitDepth != RequiredBitDepth)
        {
            throw new InvalidDataException("WAV audio parameters violate CXone outbound media constraints.");
        }
    }
}

Step 3: Handle WAV Encoding via Atomic PUT with Checksum and Format Verification

Uploading recordings requires an atomic PUT operation to /api/v2/media/recordings. The request must include a computed MD5 checksum for integrity verification, explicit content type headers, and retry logic for rate limit responses.

using System.Net.Http;
using System.Security.Cryptography;
using System.Text;

public static async Task<string> UploadRecordingAsync(HttpClient client, byte[] wavData, string recordingId, ILogger logger)
{
    var md5Hash = MD5.Create().ComputeHash(wavData);
    var checksum = Convert.ToBase64String(md5Hash);

    var content = new ByteArrayContent(wavData);
    content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("audio/wav");
    content.Headers.Add("Content-MD5", checksum);
    content.Headers.Add("X-Recording-Id", recordingId);

    int retryCount = 0;
    const int maxRetries = 3;
    TimeSpan delay = TimeSpan.FromSeconds(1);

    while (true)
    {
        try
        {
            var response = await client.PutAsync($"/api/v2/media/recordings/{recordingId}", content);

            if (response.StatusCode == System.Net.HttpStatusCode.TooManyRequests)
            {
                retryCount++;
                if (retryCount > maxRetries)
                {
                    throw new HttpRequestException("429 Too Many Requests: Exhausted retry attempts.");
                }
                logger.LogWarning("Received 429. Retrying in {Delay} seconds. Attempt {Attempt}", delay.TotalSeconds, retryCount);
                await Task.Delay(delay);
                delay = delay * 2;
                continue;
            }

            response.EnsureSuccessStatusCode();

            var result = await response.Content.ReadAsStringAsync();
            logger.LogInformation("Recording {RecordingId} uploaded successfully. Checksum verified.", recordingId);
            return result;
        }
        catch (HttpRequestException ex) when (ex.Message.Contains("401") || ex.Message.Contains("403"))
        {
            throw new UnauthorizedAccessException("Authentication or authorization failed during recording upload.", ex);
        }
        catch (Exception ex) when (ex is not HttpRequestException)
        {
            throw new InvalidOperationException($"Upload failed for {recordingId}: {ex.Message}", ex);
        }
    }
}

Required OAuth scopes: recordings:write. The Content-MD5 header triggers automatic checksum verification on the CXone media engine side. If the computed hash does not match the payload, the server returns a 400 Bad Request.

Step 4: Implement Validation Pipelines, Webhook Synchronization, and Audit Logging

Compliance recording requires duration threshold checking, silence suppression verification, webhook registration for external storage synchronization, latency tracking, and structured audit logging.

using System.Diagnostics;
using System.Text.Json;

public record AuditLogEntry(
    string Timestamp,
    string Action,
    string DisclaimerId,
    string RecordingId,
    double LatencyMs,
    bool Success,
    string? ErrorMessage);

public static class CompliancePipeline
{
    public static bool ValidateDurationAndSilence(byte[] wavData, TimeSpan minDuration, TimeSpan maxDuration)
    {
        var byteRate = BitConverter.ToInt32(wavData, 28);
        var dataSize = BitConverter.ToInt32(wavData, 40);
        var duration = TimeSpan.FromSeconds(dataSize / (double)byteRate);

        if (duration < minDuration || duration > maxDuration)
        {
            return false;
        }

        var silenceThreshold = 32;
        var silenceFrames = 0;
        var totalFrames = dataSize / 2;

        for (int i = 36 + 8; i < wavData.Length - 1; i += 2)
        {
            short sample = BitConverter.ToInt16(wavData, i);
            if (Math.Abs(sample) < silenceThreshold)
            {
                silenceFrames++;
            }
        }

        var silenceRatio = (double)silenceFrames / totalFrames;
        return silenceRatio < 0.4;
    }

    public static async Task RegisterWebhookAsync(HttpClient client, string webhookUrl, ILogger logger)
    {
        var payload = new
        {
            name = "disclaimer_recorded_sync",
            url = webhookUrl,
            events = new[] { "disclaimer.recorded" },
            enabled = true
        };

        var json = JsonSerializer.Serialize(payload);
        var content = new StringContent(json, Encoding.UTF8, "application/json");

        var response = await client.PostAsync("/api/v2/webhooks", content);
        response.EnsureSuccessStatusCode();

        logger.LogInformation("Webhook registered for disclaimer.recorded events at {Url}", webhookUrl);
    }

    public static AuditLogEntry CreateAuditLog(string disclaimerId, string recordingId, double latencyMs, bool success, string? error = null)
    {
        return new AuditLogEntry(
            Timestamp: DateTime.UtcNow.ToString("O"),
            Action: "DISCLAIMER_RECORDING_UPLOAD",
            DisclaimerId: disclaimerId,
            RecordingId: recordingId,
            LatencyMs: latencyMs,
            Success: success,
            ErrorMessage: error);
    }
}

Required OAuth scopes for webhook registration: webhooks:write. The pipeline validates audio duration against campaign thresholds, computes silence ratios to prevent truncated playback, and generates structured audit entries for compliance governance.

Complete Working Example

The following class integrates all components into a production-ready service. It handles authentication, payload construction, validation, atomic upload, webhook synchronization, metrics tracking, and audit logging.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

public class DisclaimerRecorderService
{
    private readonly CxoneAuthClient _authClient;
    private readonly ILogger<DisclaimerRecorderService> _logger;
    private readonly TimeSpan _minDuration = TimeSpan.FromSeconds(2);
    private readonly TimeSpan _maxDuration = TimeSpan.FromSeconds(30);
    private readonly Dictionary<string, int> _successMetrics = new();
    private readonly Dictionary<string, int> _failureMetrics = new();

    public DisclaimerRecorderService(string cxoneBaseUrl, string clientId, string clientSecret, ILogger<DisclaimerRecorderService> logger)
    {
        _authClient = new CxoneAuthClient(cxoneBaseUrl, clientId, clientSecret);
        _logger = logger;
    }

    public async Task<RecordingResult> ProcessDisclaimerAsync(string disclaimerId, string campaignId, byte[] wavData)
    {
        var stopwatch = Stopwatch.StartNew();
        var recordingId = $"DIS_{disclaimerId}_{Guid.NewGuid():N}";

        try
        {
            var payload = PayloadFactory.Create(disclaimerId, campaignId);
            AudioValidator.ValidateAudioMatrix(payload.AudioMatrix);
            AudioValidator.ValidateWavHeader(wavData);

            if (!CompliancePipeline.ValidateDurationAndSilence(wavData, _minDuration, _maxDuration))
            {
                throw new InvalidDataException("Audio failed duration or silence suppression validation.");
            }

            var client = await _authClient.CreateAuthenticatedClientAsync();
            var uploadResult = await UploadRecordingAsync(client, wavData, recordingId, _logger);

            stopwatch.Stop();
            _successMetrics[disclaimerId] = _successMetrics.GetValueOrDefault(disclaimerId, 0) + 1;

            var auditEntry = CompliancePipeline.CreateAuditLog(disclaimerId, recordingId, stopwatch.Elapsed.TotalMilliseconds, true);
            _logger.LogInformation("Audit: {Audit}", JsonSerializer.Serialize(auditEntry));

            return new RecordingResult(true, recordingId, uploadResult, stopwatch.Elapsed.TotalMilliseconds);
        }
        catch (Exception ex)
        {
            stopwatch.Stop();
            _failureMetrics[disclaimerId] = _failureMetrics.GetValueOrDefault(disclaimerId, 0) + 1;

            var auditEntry = CompliancePipeline.CreateAuditLog(disclaimerId, recordingId, stopwatch.Elapsed.TotalMilliseconds, false, ex.Message);
            _logger.LogError("Audit: {Audit}", JsonSerializer.Serialize(auditEntry));

            return new RecordingResult(false, recordingId, null, stopwatch.Elapsed.TotalMilliseconds, ex.Message);
        }
    }

    public async Task SynchronizeWebhookAsync(string webhookUrl)
    {
        var client = await _authClient.CreateAuthenticatedClientAsync();
        await CompliancePipeline.RegisterWebhookAsync(client, webhookUrl, _logger);
    }

    public Dictionary<string, int> GetSuccessMetrics() => new(_successMetrics);
    public Dictionary<string, int> GetFailureMetrics() => new(_failureMetrics);

    private static async Task<string> UploadRecordingAsync(HttpClient client, byte[] wavData, string recordingId, ILogger logger)
    {
        var md5Hash = System.Security.Cryptography.MD5.Create().ComputeHash(wavData);
        var checksum = Convert.ToBase64String(md5Hash);

        var content = new ByteArrayContent(wavData);
        content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("audio/wav");
        content.Headers.Add("Content-MD5", checksum);
        content.Headers.Add("X-Recording-Id", recordingId);

        int retryCount = 0;
        const int maxRetries = 3;
        TimeSpan delay = TimeSpan.FromSeconds(1);

        while (true)
        {
            var response = await client.PutAsync($"/api/v2/media/recordings/{recordingId}", content);

            if (response.StatusCode == System.Net.HttpStatusCode.TooManyRequests)
            {
                retryCount++;
                if (retryCount > maxRetries)
                {
                    throw new HttpRequestException("429 Too Many Requests: Exhausted retry attempts.");
                }
                logger.LogWarning("Received 429. Retrying in {Delay} seconds.", delay.TotalSeconds);
                await Task.Delay(delay);
                delay = delay * 2;
                continue;
            }

            response.EnsureSuccessStatusCode();
            return await response.Content.ReadAsStringAsync();
        }
    }
}

public record RecordingResult(bool Success, string RecordingId, string? ResponsePayload, double LatencyMs, string? Error = null);

Common Errors & Debugging

Error: 400 Bad Request (Invalid WAV Header or Audio Matrix)

• Cause: The WAV file contains multi-channel audio, exceeds 8000 Hz sample rate, or uses a bit depth other than 16. The CXone media engine rejects non-compliant formats before processing.
• Fix: Resample audio to 8000 Hz mono 16-bit PCM before passing it to the service. Use FFmpeg or NAudio for conversion. Verify the header bytes match RIFF and WAVE signatures.
• Code Fix: Run AudioValidator.ValidateWavHeader() locally before upload. If it throws, convert the source file.

Error: 401 Unauthorized or 403 Forbidden

• Cause: The OAuth token expired during a long-running batch operation, or the client credentials lack recordings:write or campaigns:write scopes.
• Fix: Ensure the CxoneAuthClient caches tokens and refreshes before expiry. Verify the OAuth client in the CXone admin portal has the required scopes assigned.
• Code Fix: The GetAccessTokenAsync() method includes a 5-minute buffer before expiry. If you receive 401, force a token refresh by clearing _cachedToken.

Error: 429 Too Many Requests

• Cause: CXone enforces per-tenant and per-endpoint rate limits. Bulk disclaimer uploads trigger cascading limits when concurrent requests exceed thresholds.
• Fix: Implement exponential backoff. The UploadRecordingAsync method includes a retry loop with doubling delays. For large batches, serialize uploads or add a delay between iterations.
• Code Fix: Monitor the Retry-After header if CXone returns it. The current implementation uses a fixed exponential backoff starting at 1 second.

Error: 500 Internal Server Error (Checksum Mismatch)

• Cause: The Content-MD5 header does not match the computed hash of the request body. Network proxies or compression middleware may alter the payload.
• Fix: Disable automatic gzip compression on the HttpClient for media uploads. Verify the byte array remains unmodified between hash computation and transmission.
• Code Fix: Add client.DefaultRequestHeaders.AcceptEncoding.Clear() before the PUT request to prevent content transformation.

Official References

• NICE CXone Media Recordings API Documentation
• NICE CXone Outbound Disclaimers API Documentation
• NICE CXone Webhook Management API Documentation
• NICE CXone OAuth 2.0 Client Credentials Flow
• NICE CXone C# SDK Reference