Telnyx Voice Java

Telnyx Voice - Java

Installation

<!-- Maven -->
<dependency>
    <groupId>com.telnyx.sdk</groupId>
    <artifactId>telnyx</artifactId>
    <version>6.89.0</version>
</dependency>

// Gradle
implementation("com.telnyx.sdk:telnyx:6.89.0")

Setup

import com.telnyx.sdk.client.TelnyxClient;
import com.telnyx.sdk.client.okhttp.TelnyxOkHttpClient;

TelnyxClient client = TelnyxOkHttpClient.fromEnv();

All examples below assume client is already initialized as shown above.

Error Handling

All API calls can fail with network errors, rate limits (429), validation errors (422), or authentication errors (401). Always handle errors in production code:

import com.telnyx.sdk.models.calls.CallDialParams;
import com.telnyx.sdk.models.calls.CallDialResponse;
CallDialParams params = CallDialParams.builder()
    .connectionId("7267xxxxxxxxxxxxxx")
    .from("+18005550101")
    .to("+18005550100;secure=srtp")
    .build();
CallDialResponse response = client.calls().dial(params);

Common error codes: 401 invalid API key, 403 insufficient permissions, 404 resource not found, 422 validation error (check field formats), 429 rate limited (retry with exponential backoff).

Important Notes

• Phone numbers must be in E.164 format (e.g., +13125550001). Include the + prefix and country code. No spaces, dashes, or parentheses.
• Pagination: List methods return a page. Use .autoPager() for automatic iteration: for (var item : page.autoPager()) { ... }. For manual control, use .hasNextPage() and .nextPage().

Operational Caveats

• Call Control is event-driven. After dial() or an inbound webhook, issue follow-up commands from webhook handlers using the call_control_id in the event payload.
• Outbound and inbound flows are different: outbound calls start with dial(), while inbound calls must be answered from the incoming webhook before other commands run.
• A publicly reachable webhook endpoint is required for real call control. Without it, calls may connect but your application cannot drive the live call state.

Reference Use Rules

Do not invent Telnyx parameters, enums, response fields, or webhook fields.

• If the parameter, enum, or response field you need is not shown inline in this skill, read references/api-details.md before writing code.
• Before using any operation in ## Additional Operations, read the optional-parameters section and the response-schemas section.
• Before reading or matching webhook fields beyond the inline examples, read the webhook payload reference.

Core Tasks

Dial an outbound call

Primary voice entrypoint. Agents need the async call-control identifiers returned here.

client.calls().dial() — POST /calls

import com.telnyx.sdk.models.calls.CallDialParams;
import com.telnyx.sdk.models.calls.CallDialResponse;

CallDialParams params = CallDialParams.builder()
    .connectionId("7267xxxxxxxxxxxxxx")
    .from("+18005550101")
    .to("+18005550100;secure=srtp")
    .build();
CallDialResponse response = client.calls().dial(params);

Primary response fields:

• response.data.callControlId
• response.data.callLegId
• response.data.callSessionId
• response.data.isAlive
• response.data.recordingId
• response.data.callDuration

Answer an inbound call

Primary inbound call-control command.

client.calls().actions().answer() — POST /calls/{call_control_id}/actions/answer

import com.telnyx.sdk.models.calls.actions.ActionAnswerParams;
import com.telnyx.sdk.models.calls.actions.ActionAnswerResponse;

ActionAnswerResponse response = client.calls().actions().answer("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ");

Primary response fields:

• response.data.result
• response.data.recordingId

Transfer a live call

Common post-answer control path with downstream webhook implications.

client.calls().actions().transfer() — POST /calls/{call_control_id}/actions/transfer

import com.telnyx.sdk.models.calls.actions.ActionTransferParams;
import com.telnyx.sdk.models.calls.actions.ActionTransferResponse;

ActionTransferParams params = ActionTransferParams.builder()
    .callControlId("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ")
    .to("+18005550100;secure=srtp")
    .build();
ActionTransferResponse response = client.calls().actions().transfer(params);

Primary response fields:

• response.data.result

Webhook Verification

Telnyx signs webhooks with Ed25519. Each request includes telnyx-signature-ed25519 and telnyx-timestamp headers. Always verify signatures in production:

import com.telnyx.sdk.core.UnwrapWebhookParams;
import com.telnyx.sdk.core.http.Headers;

// In your webhook handler (e.g., Spring — use raw body):
@PostMapping("/webhooks")
public ResponseEntity<String> handleWebhook(
    @RequestBody String payload,
    HttpServletRequest request) {
  try {
    Headers headers = Headers.builder()
        .put("telnyx-signature-ed25519", request.getHeader("telnyx-signature-ed25519"))
        .put("telnyx-timestamp", request.getHeader("telnyx-timestamp"))
        .build();
    var event = client.webhooks().unwrap(
        UnwrapWebhookParams.builder()
            .body(payload)
            .headers(headers)
            .build());
    // Signature valid — process the event
    System.out.println("Received webhook event");
    return ResponseEntity.ok("OK");
  } catch (Exception e) {
    System.err.println("Webhook verification failed: " + e.getMessage());
    return ResponseEntity.badRequest().body("Invalid signature");
  }
}

Webhooks

These webhook payload fields are inline because they are part of the primary integration path.

Call Answered

Call Hangup

Call Initiated

If you need webhook fields that are not listed inline here, read the webhook payload reference before writing the handler.

Important Supporting Operations

Use these when the core tasks above are close to your flow, but you need a common variation or follow-up step.

Hangup call

End a live call from your webhook-driven control flow.

client.calls().actions().hangup() — POST /calls/{call_control_id}/actions/hangup

import com.telnyx.sdk.models.calls.actions.ActionHangupParams;
import com.telnyx.sdk.models.calls.actions.ActionHangupResponse;

ActionHangupResponse response = client.calls().actions().hangup("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ");

Primary response fields:

• response.data.result

Bridge calls

Trigger a follow-up action in an existing workflow rather than creating a new top-level resource.

client.calls().actions().bridge() — POST /calls/{call_control_id}/actions/bridge

import com.telnyx.sdk.models.calls.actions.ActionBridgeParams;
import com.telnyx.sdk.models.calls.actions.ActionBridgeResponse;

ActionBridgeParams params = ActionBridgeParams.builder()
    .callControlIdToBridge("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ")
    .callControlId("v3:MdI91X4lWFEs7IgbBEOT9M4AigoY08M0WWZFISt1Yw2axZ_IiE4pqg")
    .build();
ActionBridgeResponse response = client.calls().actions().bridge(params);

Primary response fields:

• response.data.result

Reject a call

Trigger a follow-up action in an existing workflow rather than creating a new top-level resource.

client.calls().actions().reject() — POST /calls/{call_control_id}/actions/reject

import com.telnyx.sdk.models.calls.actions.ActionRejectParams;
import com.telnyx.sdk.models.calls.actions.ActionRejectResponse;

ActionRejectParams params = ActionRejectParams.builder()
    .callControlId("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ")
    .cause(ActionRejectParams.Cause.USER_BUSY)
    .build();
ActionRejectResponse response = client.calls().actions().reject(params);

Primary response fields:

• response.data.result

Retrieve a call status

Fetch the current state before updating, deleting, or making control-flow decisions.

client.calls().retrieveStatus() — GET /calls/{call_control_id}

import com.telnyx.sdk.models.calls.CallRetrieveStatusParams;
import com.telnyx.sdk.models.calls.CallRetrieveStatusResponse;

CallRetrieveStatusResponse response = client.calls().retrieveStatus("v3:550e8400-e29b-41d4-a716-446655440000_gRU1OGRkYQ");

Primary response fields:

• response.data.callControlId
• response.data.callDuration
• response.data.callLegId
• response.data.callSessionId
• response.data.clientState
• response.data.endTime

List all active calls for given connection

Fetch the current state before updating, deleting, or making control-flow decisions.

client.connections().listActiveCalls() — GET /connections/{connection_id}/active_calls

import com.telnyx.sdk.models.connections.ConnectionListActiveCallsPage;
import com.telnyx.sdk.models.connections.ConnectionListActiveCallsParams;

ConnectionListActiveCallsPage page = client.connections().listActiveCalls("1293384261075731461");

Response wrapper:

• items: page.data
• pagination: page.meta

Primary item fields:

• callControlId
• callDuration
• callLegId
• callSessionId
• clientState
• recordType

List call control applications

Inspect available resources or choose an existing resource before mutating it.

client.callControlApplications().list() — GET /call_control_applications

import com.telnyx.sdk.models.callcontrolapplications.CallControlApplicationListPage;
import com.telnyx.sdk.models.callcontrolapplications.CallControlApplicationListParams;

CallControlApplicationListPage page = client.callControlApplications().list();

Response wrapper:

• items: page.data
• pagination: page.meta

Primary item fields:

• id
• createdAt
• updatedAt
• active
• anchorsiteOverride
• applicationName

Additional Operations

Use the core tasks above first. The operations below are indexed here with exact SDK methods and required params; use references/api-details.md for full optional params, response schemas, and lower-frequency webhook payloads. Before using any operation below, read the optional-parameters section and the response-schemas section so you do not guess missing fields.

Other Webhook Events

For exhaustive optional parameters, full response schemas, and complete webhook payloads, see references/api-details.md.