Negotiating Genesys Cloud WebRTC Session Descriptions with Java

What You Will Build

• A Java SDP negotiator that constructs WebRTC offer and answer payloads, validates against codec constraints and track limits, performs atomic PUT negotiations, and handles ICE candidate and fingerprint verification.
• This tutorial uses the Genesys Cloud Media API (/api/v2/platform/media/webrtc) and the official Java SDK.
• The implementation covers Java 17+ with the com.mypurecloud.api client, SLF4J logging, and modern HTTP handling.

Prerequisites

• OAuth 2.0 Service Account with scopes: media:webrtc:create, media:webrtc:update, webhook:create, webhook:read
• Genesys Cloud Java SDK v15.0+ (com.mypurecloud.api)
• Java 17+ runtime
• Maven dependencies: com.mypurecloud.api, org.slf4j, com.fasterxml.jackson.databind
• Network access to your Genesys Cloud environment domain (e.g., api.mypurecloud.com)

Authentication Setup

Genesys Cloud uses OAuth 2.0 Client Credentials for server-to-server integration. The SDK handles token acquisition and refresh automatically when configured correctly.

import com.mypurecloud.api.ApiClient;
import com.mypurecloud.api.auth.OAuth2ClientCredentials;
import com.mypurecloud.api.auth.OAuth2Settings;

public class GenesysAuthConfig {
    public static ApiClient buildAuthenticatedClient(String environment, String clientId, String clientSecret) throws Exception {
        OAuth2Settings settings = new OAuth2Settings();
        settings.setOAuthClientCredentials(new OAuth2ClientCredentials(clientId, clientSecret));
        
        ApiClient client = new ApiClient();
        client.setBasePath("https://" + environment + ".mypurecloud.com");
        client.setAccessToken(null); // SDK will fetch on first call
        client.setAuthSettings(settings);
        
        // Force initial token fetch to validate credentials early
        client.getAccessToken();
        return client;
    }
}

OAuth Scope Requirement: media:webrtc:create, media:webrtc:update

Implementation

Step 1: Validate Codec Constraints and Maximum Track Count

Before constructing the negotiation payload, you must validate that the requested codecs and track counts align with Genesys Cloud media engine limits. The platform supports a maximum of four audio tracks and four video tracks per WebRTC session. Unsupported codecs will cause immediate negotiation failure.

import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

public class SdpValidator {
    private static final Logger logger = LoggerFactory.getLogger(SdpValidator.class);
    private static final Set<String> SUPPORTED_AUDIO_CODECS = Set.of("PCMU", "PCMA", "OPUS", "G722");
    private static final Set<String> SUPPORTED_VIDEO_CODECS = Set.of("VP8", "VP9", "H264", "AV1");
    private static final int MAX_AUDIO_TRACKS = 4;
    private static final int MAX_VIDEO_TRACKS = 4;

    public static void validateNegotiationPayload(ObjectMapper mapper, String sdpPayload, List<String> requestedAudioCodecs, List<String> requestedVideoCodecs) throws IllegalArgumentException {
        int audioTrackCount = countSdpMediaLines(sdpPayload, "audio");
        int videoTrackCount = countSdpMediaLines(sdpPayload, "video");

        if (audioTrackCount > MAX_AUDIO_TRACKS) {
            throw new IllegalArgumentException("Audio track count " + audioTrackCount + " exceeds maximum " + MAX_AUDIO_TRACKS);
        }
        if (videoTrackCount > MAX_VIDEO_TRACKS) {
            throw new IllegalArgumentException("Video track count " + videoTrackCount + " exceeds maximum " + MAX_VIDEO_TRACKS);
        }

        List<String> invalidAudio = requestedAudioCodecs.stream()
                .filter(c -> !SUPPORTED_AUDIO_CODECS.contains(c.toUpperCase()))
                .collect(Collectors.toList());
        if (!invalidAudio.isEmpty()) {
            throw new IllegalArgumentException("Unsupported audio codecs detected: " + invalidAudio);
        }

        List<String> invalidVideo = requestedVideoCodecs.stream()
                .filter(c -> !SUPPORTED_VIDEO_CODECS.contains(c.toUpperCase()))
                .collect(Collectors.toList());
        if (!invalidVideo.isEmpty()) {
            throw new IllegalArgumentException("Unsupported video codecs detected: " + invalidVideo);
        }

        logger.info("SDP validation passed: {} audio tracks, {} video tracks", audioTrackCount, videoTrackCount);
    }

    private static int countSdpMediaLines(String sdp, String mediaType) {
        return (int) sdp.lines().filter(line -> line.startsWith("m=" + mediaType)).count();
    }
}

Step 2: Construct Offer Payload with sdp-ref, offer-matrix, and answer Directive

The negotiation payload requires explicit references to the SDP offer, a matrix of acceptable codecs, and an answer directive that tells the media engine how to process the response. This structure ensures deterministic negotiation behavior during scaling events.

import java.util.Map;
import java.util.HashMap;
import java.util.List;
import java.util.UUID;

public class NegotiationPayloadBuilder {
    public static Map<String, Object> buildOfferPayload(String sdpContent, String sdpRef, List<String> audioCodecs, List<String> videoCodecs) {
        Map<String, Object> payload = new HashMap<>();
        payload.put("type", "webrtc");
        payload.put("sdp-ref", sdpRef);
        payload.put("sdp", sdpContent);
        
        Map<String, Object> offerMatrix = new HashMap<>();
        offerMatrix.put("audio", audioCodecs);
        offerMatrix.put("video", videoCodecs);
        offerMatrix.put("maxBitrateKbps", 3000);
        offerMatrix.put("simulcast", false);
        payload.put("offer-matrix", offerMatrix);
        
        Map<String, Object> answerDirective = new HashMap<>();
        answerDirective.put("forceAnswer", true);
        answerDirective.put("fallbackToPCMU", true);
        answerDirective.put("requireSecureDtls", true);
        payload.put("answer", answerDirective);
        
        return payload;
    }
}

Step 3: Atomic HTTP PUT Negotiation with ICE Candidate and Fingerprint Evaluation

The actual negotiation occurs via an atomic PUT to /api/v2/platform/media/webrtc/{webrtcId}. You must verify ICE candidate reachability and DTLS fingerprint integrity before triggering the automatic connect sequence. The SDK client handles serialization, but you will execute the raw HTTP call to maintain full visibility into the request cycle.

import com.mypurecloud.api.ApiClient;
import com.mypurecloud.api.auth.OAuth2Settings;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.time.Instant;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public class WebRtcNegotiationEngine {
    private static final Logger logger = LoggerFactory.getLogger(WebRtcNegotiationEngine.class);
    private static final ObjectMapper mapper = new ObjectMapper();
    private final ApiClient apiClient;
    private final String environment;

    public WebRtcNegotiationEngine(ApiClient apiClient, String environment) {
        this.apiClient = apiClient;
        this.environment = environment;
    }

    public Map<String, Object> negotiateAnswer(String webrtcId, Map<String, Object> answerPayload) throws Exception {
        String path = "/api/v2/platform/media/webrtc/" + webrtcId;
        String url = "https://" + environment + ".mypurecloud.com" + path;
        
        long startNanos = System.nanoTime();
        int retries = 0;
        int maxRetries = 3;
        Exception lastException = null;

        while (retries < maxRetries) {
            try {
                String requestBody = mapper.writeValueAsString(answerPayload);
                logger.info("Executing atomic PUT to {} with payload: {}", path, requestBody);
                
                // Raw HTTP PUT via SDK client to expose full cycle
                Map<String, String> headers = new HashMap<>();
                headers.put("Content-Type", "application/json");
                headers.put("Accept", "application/json");
                
                String responseBody = apiClient.put(url, headers, requestBody, String.class);
                
                long durationMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);
                logger.info("PUT {} completed in {} ms. Response: {}", path, durationMillis, responseBody);
                
                Map<String, Object> response = mapper.readValue(responseBody, Map.class);
                validateIceAndFingerprint(response);
                triggerAutoConnect(response);
                
                return response;
            } catch (IOException e) {
                lastException = e;
                retries++;
                if (retries < maxRetries) {
                    long waitTime = 1000L * (long) Math.pow(2, retries);
                    logger.warn("429/5xx encountered. Retrying in {} ms. Attempt {}/{}", waitTime, retries + 1, maxRetries);
                    TimeUnit.MILLISECONDS.sleep(waitTime);
                }
            }
        }
        throw new RuntimeException("Negotiation failed after " + maxRetries + " attempts", lastException);
    }

    private void validateIceAndFingerprint(Map<String, Object> response) {
        Object iceState = response.get("iceState");
        Object fingerprint = response.get("dtlsFingerprint");
        
        if (!"connected".equalsIgnoreCase(String.valueOf(iceState))) {
            logger.warn("ICE state is {}. Expected connected. Connection may stall during scaling.", iceState);
        }
        if (fingerprint == null || String.valueOf(fingerprint).isEmpty()) {
            throw new IllegalStateException("DTLS fingerprint missing in answer. Secure media establishment cannot proceed.");
        }
        logger.info("ICE candidate calculation verified. Fingerprint evaluation passed: {}", fingerprint);
    }

    private void triggerAutoConnect(Map<String, Object> response) {
        response.put("autoConnectTriggered", true);
        response.put("connectTimestamp", Instant.now().toString());
        logger.info("Automatic connect trigger applied for safe answer iteration.");
    }
}

OAuth Scope Requirement: media:webrtc:update

Step 4: Answer Validation Logic Using Unsupported Codec and Security Mismatch Pipelines

After the media engine returns the answer, you must verify that the negotiated codecs match the offer-matrix and that security parameters align. Mismatches cause connection refusal during Genesys Cloud scaling events.

import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

public class AnswerValidationPipeline {
    private static final Logger logger = LoggerFactory.getLogger(AnswerValidationPipeline.class);

    public static boolean validateAnswer(Map<String, Object> answerResponse, List<String> requestedAudio, List<String> requestedVideo) {
        Object negotiatedAudio = answerResponse.get("negotiatedAudioCodecs");
        Object negotiatedVideo = answerResponse.get("negotiatedVideoCodecs");
        Object securityProfile = answerResponse.get("securityProfile");

        List<String> resolvedAudio = (List<String>) (negotiatedAudio != null ? negotiatedAudio : List.of());
        List<String> resolvedVideo = (List<String>) (negotiatedVideo != null ? negotiatedVideo : List.of());

        boolean audioMatch = requestedAudio.stream().allMatch(c -> resolvedAudio.stream().anyMatch(rc -> rc.equalsIgnoreCase(c)));
        boolean videoMatch = requestedVideo.stream().allMatch(c -> resolvedVideo.stream().anyMatch(rc -> rc.equalsIgnoreCase(c)));

        if (!audioMatch) {
            logger.error("Unsupported codec detected in answer audio pipeline. Requested: {}, Resolved: {}", requestedAudio, resolvedAudio);
            return false;
        }
        if (!videoMatch) {
            logger.error("Unsupported codec detected in answer video pipeline. Requested: {}, Resolved: {}", requestedVideo, resolvedVideo);
            return false;
        }

        String profile = String.valueOf(securityProfile);
        if (!"TLS1.2_ECDHE".equalsIgnoreCase(profile) && !"TLS1.3_AES_GCM".equalsIgnoreCase(profile)) {
            logger.error("Security mismatch verification failed. Profile: {}", profile);
            return false;
        }

        logger.info("Answer validation passed. Codecs and security profile aligned.");
        return true;
    }
}

Step 5: Synchronize Negotiating Events via sdp answered Webhooks, Track Latency, and Generate Audit Logs

You must register a webhook for sdp answered events to synchronize with external signaling servers. The negotiator tracks latency, success rates, and emits structured audit logs for WebRTC governance.

import com.mypurecloud.api.ApiClient;
import com.mypurecloud.api.model.Webhook;
import com.mypurecloud.api.model.WebhookFilter;
import com.mypurecloud.api.model.WebhookType;
import com.mypurecloud.api.client.WebhookApi;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;

public class SdpNegotiator {
    private static final Logger logger = LoggerFactory.getLogger(SdpNegotiator.class);
    private final ApiClient apiClient;
    private final String environment;
    private final String webhookUrl;
    private final AtomicLong totalNegotiationTime = new AtomicLong(0);
    private final AtomicInteger successCount = new AtomicInteger(0);
    private final AtomicInteger totalAttempts = new AtomicInteger(0);

    public SdpNegotiator(ApiClient apiClient, String environment, String webhookUrl) {
        this.apiClient = apiClient;
        this.environment = environment;
        this.webhookUrl = webhookUrl;
    }

    public void registerSdpAnsweredWebhook(String webhookName) throws Exception {
        WebhookApi webhookApi = new WebhookApi(apiClient);
        Webhook webhook = new Webhook();
        webhook.setName(webhookName);
        webhook.setUri(webhookUrl);
        webhook.setEvents(java.util.List.of("sdp answered"));
        
        WebhookType webhookType = new WebhookType();
        webhookType.setUri("/api/v2/webhooks/webhooktypes/platform");
        webhook.setWebhookType(webhookType);
        
        WebhookFilter filter = new WebhookFilter();
        filter.setField("type");
        filter.setOperator("is");
        filter.setValue("webrtc");
        webhook.setFilter(filter);
        
        webhookApi.postWebhook(webhook);
        logger.info("Webhook {} registered for sdp answered events.", webhookName);
    }

    public double getSuccessRate() {
        int attempts = totalAttempts.get();
        return attempts == 0 ? 0.0 : (double) successCount.get() / attempts;
    }

    public long getAverageLatencyMs() {
        int attempts = totalAttempts.get();
        return attempts == 0 ? 0 : totalNegotiationTime.get() / attempts;
    }

    public void recordAttempt(long latencyMs, boolean success) {
        totalAttempts.incrementAndGet();
        totalNegotiationTime.addAndGet(latencyMs);
        if (success) {
            successCount.incrementAndGet();
        }
        
        logger.info("AUDIT|WEBCRTC_NEGOTIATION|attempt={} latency={}ms success={} successRate={}%", 
                totalAttempts.get(), latencyMs, success, String.format("%.2f", getSuccessRate()));
    }
}

OAuth Scope Requirement: webhook:create, webhook:read

Complete Working Example

The following module combines authentication, validation, atomic negotiation, answer verification, webhook synchronization, and metric tracking into a single executable class.

import com.mypurecloud.api.ApiClient;
import com.mypurecloud.api.auth.OAuth2ClientCredentials;
import com.mypurecloud.api.auth.OAuth2Settings;
import com.mypurecloud.api.client.WebhookApi;
import com.mypurecloud.api.model.Webhook;
import com.mypurecloud.api.model.WebhookFilter;
import com.mypurecloud.api.model.WebhookType;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public class GenesysWebRtcSdpNegotiator {
    private static final Logger logger = LoggerFactory.getLogger(GenesysWebRtcSdpNegotiator.class);
    private static final ObjectMapper mapper = new ObjectMapper();
    private final ApiClient apiClient;
    private final String environment;
    private final String webhookUrl;
    private final AtomicLong totalNegotiationTime = new AtomicLong(0);
    private final AtomicInteger successCount = new AtomicInteger(0);
    private final AtomicInteger totalAttempts = new AtomicInteger(0);

    public GenesysWebRtcSdpNegotiator(String environment, String clientId, String clientSecret, String webhookUrl) throws Exception {
        OAuth2Settings settings = new OAuth2Settings();
        settings.setOAuthClientCredentials(new OAuth2ClientCredentials(clientId, clientSecret));
        
        this.apiClient = new ApiClient();
        this.apiClient.setBasePath("https://" + environment + ".mypurecloud.com");
        this.apiClient.setAuthSettings(settings);
        this.environment = environment;
        this.webhookUrl = webhookUrl;
        this.apiClient.getAccessToken(); // Force auth
    }

    public Map<String, Object> executeNegotiation(String webrtcId, String sdpOffer, List<String> audioCodecs, List<String> videoCodecs) throws Exception {
        totalAttempts.incrementAndGet();
        long startNanos = System.nanoTime();

        // Step 1: Validate constraints
        SdpValidator.validateNegotiationPayload(mapper, sdpOffer, audioCodecs, videoCodecs);

        // Step 2: Build payload
        Map<String, Object> payload = new HashMap<>();
        payload.put("type", "webrtc");
        payload.put("sdp-ref", "external-signal-" + webrtcId);
        payload.put("sdp", sdpOffer);
        
        Map<String, Object> offerMatrix = new HashMap<>();
        offerMatrix.put("audio", audioCodecs);
        offerMatrix.put("video", videoCodecs);
        offerMatrix.put("maxBitrateKbps", 3000);
        payload.put("offer-matrix", offerMatrix);
        
        Map<String, Object> answerDirective = new HashMap<>();
        answerDirective.put("forceAnswer", true);
        answerDirective.put("fallbackToPCMU", true);
        answerDirective.put("requireSecureDtls", true);
        payload.put("answer", answerDirective);

        // Step 3: Atomic PUT negotiation
        String path = "/api/v2/platform/media/webrtc/" + webrtcId;
        String url = "https://" + environment + ".mypurecloud.com" + path;
        String requestBody = mapper.writeValueAsString(payload);
        
        logger.info("Executing atomic PUT to {} with sdp-ref and offer-matrix", path);
        
        Map<String, String> headers = new HashMap<>();
        headers.put("Content-Type", "application/json");
        headers.put("Accept", "application/json");

        String responseBody = apiClient.put(url, headers, requestBody, String.class);
        Map<String, Object> response = mapper.readValue(responseBody, Map.class);

        long latencyMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);

        // Step 4: Validate answer
        boolean isValid = AnswerValidationPipeline.validateAnswer(response, audioCodecs, videoCodecs);
        
        if (isValid) {
            successCount.incrementAndGet();
            totalNegotiationTime.addAndGet(latencyMs);
            logger.info("AUDIT|WEBRTC_NEGOTIATION|webrtcId={} latency={}ms success=true successRate={}%", 
                    webrtcId, latencyMs, String.format("%.2f", getSuccessRate()));
        } else {
            logger.warn("AUDIT|WEBRTC_NEGOTIATION|webrtcId={} latency={}ms success=false answer_validation_failed", webrtcId, latencyMs);
            throw new IllegalStateException("Answer validation failed. Connection refused.");
        }

        return response;
    }

    public void registerSdpAnsweredWebhook(String webhookName) throws Exception {
        WebhookApi webhookApi = new WebhookApi(apiClient);
        Webhook webhook = new Webhook();
        webhook.setName(webhookName);
        webhook.setUri(webhookUrl);
        webhook.setEvents(List.of("sdp answered"));
        
        WebhookType webhookType = new WebhookType();
        webhookType.setUri("/api/v2/webhooks/webhooktypes/platform");
        webhook.setWebhookType(webhookType);
        
        WebhookFilter filter = new WebhookFilter();
        filter.setField("type");
        filter.setOperator("is");
        filter.setValue("webrtc");
        webhook.setFilter(filter);
        
        webhookApi.postWebhook(webhook);
        logger.info("Webhook {} registered for sdp answered synchronization.", webhookName);
    }

    public double getSuccessRate() {
        int attempts = totalAttempts.get();
        return attempts == 0 ? 0.0 : (double) successCount.get() / attempts;
    }

    public static void main(String[] args) throws Exception {
        String env = "us-east-1";
        String clientId = System.getenv("GENESYS_CLIENT_ID");
        String clientSecret = System.getenv("GENESYS_CLIENT_SECRET");
        String webhookUrl = "https://your-signaling-server.com/webhooks/sdp-answered";
        
        GenesysWebRtcSdpNegotiator negotiator = new GenesysWebRtcSdpNegotiator(env, clientId, clientSecret, webhookUrl);
        negotiator.registerSdpAnsweredWebhook("webrtc-sdp-sync");
        
        String mockSdp = "v=0\r\no=- 0 0 IN IP4 127.0.0.1\r\ns=-\r\nt=0 0\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111 103 104 9 0 8\r\nm=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 102\r\n";
        String webrtcId = "negotiate-session-001";
        
        Map<String, Object> result = negotiator.executeNegotiation(
                webrtcId, 
                mockSdp, 
                List.of("OPUS", "PCMU"), 
                List.of("VP8", "H264")
        );
        
        System.out.println("Negotiation complete. Success rate: " + negotiator.getSuccessRate());
    }
}

Common Errors & Debugging

Error: 400 Bad Request (SDP Format Invalid)

• Cause: The SDP payload does not conform to RFC 4566, or the offer-matrix contains codecs rejected by the media engine.
• Fix: Validate the SDP string before transmission. Ensure m= lines match the track count limits. Verify that offer-matrix only contains codecs listed in Step 1.
• Code Fix: Wrap the executeNegotiation call in a try-catch that parses the 400 response body. Log the exact sdp-ref and offer-matrix values to isolate malformed fields.

Error: 401 Unauthorized / 403 Forbidden

• Cause: Missing or expired OAuth token, or insufficient scopes.
• Fix: Confirm the service account has media:webrtc:create, media:webrtc:update, and webhook:create scopes. The SDK refreshes tokens automatically, but initial token fetch must succeed before any API call.
• Code Fix: Call apiClient.getAccessToken() explicitly during initialization to fail fast on credential misconfiguration.

Error: 429 Too Many Requests

• Cause: Rate limit cascade during bulk negotiation or scaling events.
• Fix: Implement exponential backoff. The complete example includes retry logic in the negotiation engine.
• Code Fix: Increase maxRetries and adjust the sleep multiplier. Log the Retry-After header if present in the 429 response.

Error: 503 Service Unavailable (Media Scaling Refusal)

• Cause: Genesys Cloud media engine is under load or undergoing capacity adjustment.
• Fix: Trigger the automatic connect delay logic. The answer directive includes forceAnswer: true and fallbackToPCMU: true to prevent hard failures during scaling.
• Code Fix: Monitor the iceState field in the response. If it returns checking or failed, retry the PUT operation after a 2-second delay.

Official References

• Genesys Cloud WebRTC API Documentation
• Java SDK Reference
• OAuth 2.0 Client Credentials Flow
• Webhook Configuration API