diff --git a/fern/advanced/sip/sip-chime.mdx b/fern/advanced/sip/sip-chime.mdx
index e09c789ed..4e3ee9941 100644
--- a/fern/advanced/sip/sip-chime.mdx
+++ b/fern/advanced/sip/sip-chime.mdx
@@ -6,6 +6,12 @@ slug: advanced/sip/amazon-chime
This guide walks you through setting up both outbound and inbound SIP trunking between Amazon Chime SDK and Vapi using a Voice Connector.
+This is a **Voice Connector-only** integration — inbound and outbound calls work with no Lambda functions or custom logic required. Vapi handles the AI assistant entirely. This approach is best for straightforward AI assistants on a phone number where no additional integration is needed.
+
+
+This integration does not support passing custom SIP headers, metadata, or enriched escalation data (e.g., human transfer with SIP header context). For those use cases, use a **SIP Media Application** with **CallAndBridge** instead.
+
+
## Prerequisites
- An AWS account with access to the [Amazon Chime SDK console](https://console.aws.amazon.com/chime-sdk/)
@@ -180,20 +186,16 @@ curl -X POST https://api.vapi.ai/call/phone \
-## Inbound calls (Vapi to Chime SDK)
+## Inbound calls (Chime SDK to Vapi)
-For inbound calls, a caller dials your Chime SDK phone number. The call flows through a SIP Rule, SIP Media Application, and Lambda function that bridges the call to Vapi via the Voice Connector:
+For inbound calls, a caller dials your Chime SDK phone number. The Voice Connector routes the call to Vapi through its origination settings — no Lambda or SIP Media Application required:
```mermaid
graph LR
A[Caller] --> B[Chime Phone Number]
- B --> C[SIP Rule]
- C --> D[SIP Media Application]
- D --> E[Lambda]
- E --> F[CallAndBridge]
- F --> G[Voice Connector]
- G --> H[sip.vapi.ai]
- H --> I[Vapi AI Assistant]
+ B --> C[Voice Connector]
+ C --> D[sip.vapi.ai]
+ D --> E[Vapi AI Assistant]
```
### Vapi configuration
@@ -240,7 +242,7 @@ Save the returned `id` — this is your **Credential ID** used in the following
-Register a SIP phone number in Vapi, linking it to the credential and your assistant.
+Register your Chime SDK phone number in Vapi, linking it to the credential and your assistant:
```bash
curl -X POST https://api.vapi.ai/phone-number \
@@ -249,17 +251,16 @@ curl -X POST https://api.vapi.ai/phone-number \
-d '{
"provider": "byo-phone-number",
"name": "Chime SDK Number",
- "number": "YOUR_SIP_USERNAME",
- "numberE164CheckEnabled": false,
+ "number": "YOUR_CHIME_PHONE_NUMBER",
+ "numberE164CheckEnabled": true,
"credentialId": "YOUR_CREDENTIAL_ID",
"assistantId": "YOUR_ASSISTANT_ID"
}'
```
-
-The SIP username can be any string — it does not need to be a phone number. This value becomes the user portion of the SIP URI that the Voice Connector sends calls to.
-
-
+
+The `number` field must exactly match the E.164 phone number assigned to your Voice Connector (e.g., `+18312168445`). Inbound calls will fail to route if the numbers don't match.
+
@@ -269,27 +270,13 @@ The SIP username can be any string — it does not need to be a phone number. Th
-
-
-In the AWS Chime SDK console, go to **Phone Number Management** and either provision a new phone number or update an existing one.
-
-Set the **Product type** to **SIP Media Application Dial-In**.
-
-
-
-
-If the phone number is already assigned to a Voice Connector, you must first unassign it and save before changing the product type.
-
-
-
-
Navigate to your Voice Connector's **Origination** tab and set **Origination status** to **Enabled**.
-Click **New** to add an inbound route pointing to Vapi's SIP server so the Voice Connector knows where to send outbound SIP INVITEs:
+Click **New** to add an inbound route pointing to Vapi's SIP server:
- **Host:** `YOUR_CREDENTIAL_ID.sip.vapi.ai`
- **Port:** `5061` (for encrypted connections)
@@ -299,118 +286,11 @@ Click **New** to add an inbound route pointing to Vapi's SIP server so the Voice
-
-
-This Lambda handles inbound call events from the SIP Media Application and bridges the call to Vapi via the Voice Connector.
-
-Create a new Lambda function (**Node.js 18.x** or later) in the **same region** as your Chime SDK resources:
-
-```javascript title="index.mjs"
-exports.handler = async (event) => {
- console.log("Event:", JSON.stringify(event, null, 2));
-
- const eventType = event.InvocationEventType;
-
- switch (eventType) {
- case "NEW_INBOUND_CALL":
- return handleNewCall(event);
-
- case "ACTION_SUCCESSFUL":
- console.log("Action successful:", event.ActionData?.Type);
- return { SchemaVersion: "1.0", Actions: [] };
-
- case "ACTION_FAILED":
- console.log("Action failed:", JSON.stringify(event.ActionData));
- return {
- SchemaVersion: "1.0",
- Actions: [{ Type: "Hangup", Parameters: { SipResponseCode: "503" } }],
- };
-
- case "HANGUP":
- console.log("Call ended");
- return { SchemaVersion: "1.0", Actions: [] };
-
- default:
- console.log("Unhandled event:", eventType);
- return { SchemaVersion: "1.0", Actions: [] };
- }
-};
-
-function handleNewCall(event) {
- const callerNumber = event.CallDetails.Participants[0].From;
-
- const voiceConnectorArn =
- "arn:aws:chime:REGION:ACCOUNT_ID:vc/YOUR_VOICE_CONNECTOR_ID";
-
- const vapiSipUser = "YOUR_UNIQUE_USERNAME";
-
- return {
- SchemaVersion: "1.0",
- Actions: [
- {
- Type: "CallAndBridge",
- Parameters: {
- CallTimeoutSeconds: 30,
- CallerIdNumber: callerNumber,
- Endpoints: [
- {
- BridgeEndpointType: "AWS",
- Arn: voiceConnectorArn,
- Uri: vapiSipUser,
- },
- ],
- },
- },
- ],
- };
-}
-```
-
-Replace the following placeholders:
-- `REGION` — your AWS region (e.g., `us-west-2`)
-- `ACCOUNT_ID` — your AWS account ID
-- `YOUR_VOICE_CONNECTOR_ID` — your Voice Connector ID
-- `YOUR_UNIQUE_USERNAME` — the SIP username you configured in the Vapi phone number step
-
-The `Uri` field is the user portion of the SIP request. The Voice Connector sends the INVITE to the origination host (`sip.vapi.ai`) with this value as the user, resulting in `sip:YOUR_UNIQUE_USERNAME@YOUR_CREDENTIAL_ID.sip.vapi.ai`.
-
-
-The Lambda needs no special Chime SDK permissions — the SMA invokes it directly. Ensure the execution role has **AWSLambdaBasicExecutionRole** for CloudWatch logging.
-
-
-
-
-
-
-In the Chime SDK console, go to **SIP media applications** and create a new one. Enter a name and the **Lambda function ARN** from the previous step.
-
-
-
-Note the returned **SIP Media Application ID**.
-
-
-
-
-
-The SIP rule connects your provisioned phone number to the SIP Media Application. When a call arrives at your phone number, Chime invokes the SMA, which triggers the Lambda, which bridges the call to Vapi.
-
-In the Chime SDK console, go to **SIP rules** and create a new one:
-
-- **Trigger type:** To phone number
-- **Phone number:** Select your provisioned number
-- **SIP media application:** Select the SMA you created
-
-
-
-
-
-Call your Chime SDK phone number from any phone.
+Call your Chime SDK phone number from any phone. The call routes through the Voice Connector's origination settings to `sip.vapi.ai`, where your Vapi assistant answers.
-To debug issues:
-- Check **CloudWatch Logs** for the Lambda function to see event payloads and errors.
-- Enable **SIP logging** on the Voice Connector (under the **Logging** tab) for detailed SIP message traces.
+To debug issues, enable **SIP logging** on the Voice Connector (under the **Logging** tab) for detailed SIP message traces.