Serverless

The serverless SDK is a lightweight JavaScript SDK optimized for serverless environments and compatible with any platform. The serverless SDK provides the same functionality as all other Statsig server SDKs.

1. Install the Statsig SDK

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   npm install @statsig/serverless-client
   

2. Import the Statsig SDK

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   import {StatsigServerlessClient} from '@statsig/serverless-client'
   

3. Create a StatsigServerlessClient instance

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   const client = new StatsigServerlessClient(process.env.STATSIG_KEY)
   

   The client instantiation takes two arguments:

   • sdkKey : string Your Statsig client API key. Available from the Project Settings page in the Statsig Console. Statsig uses this to authenticate requests.
   • options : StatsigOptions Refer to StatsigOptions for more options.

4. Client Initialization

   This line initializes the client by loading feature gate and experiment configurations over the network.

   javascript

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   const init = await client.initializeAsync();
   

5. Checking a Gate

   javascript

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   const GateResult = client.checkGate('pass_gate', user);
   

   The checkGate method takes two arguments:

   • name : string The name of the Statsig gate that you are checking.
   • user : StatsigUser The Statsig user object for whom the gate is checked. For more information on the user object, refer to StatsigUser.

   Refer to the JavaScript on-device evaluation SDK documentation for how to check other entities like experiments and dynamic configs.

6. Logging an Event

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   client.logEvent('gate_check', { userID: randomUserId });
   

   The logEvent method takes two parameters:

   • eventOrName : string | StatsigEvent The name and details of the event you are logging.
   • user : StatsigUser The Statsig user object for whom the event is logged.

   For more information on event logging, refer to Logging an Event.

7. javascript

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   client.flush();
   

   This flushes all events from the SDK to Statsig. Without this, diagnostic information and logged event data won't appear in the Statsig Console.

Putting it all together

import { StatsigServerlessClient } from '@statsig/serverless-client';

export default async function handler(request) {
    const client = new StatsigServerlessClient(process.env.STATSIG_KEY);
    
    let init = await client.initializeAsync();
    
    const user = { userID: Math.random().toString().substring(2, 5) };
    const passed = client.checkGate('pass_gate', user);
    
    client.logEvent('serverless_event', user, passed.toString());
    
    client.flush();

    return new Response(
      JSON.stringify({ passed, user }),
    );
}

Bootstrapping

Use the serverless SDK to bootstrap your client SDK.

// Get client initialize response for a user
const values = statsig.getClientInitializeResponse(user, options);

// Pass values to a client SDK to initialize without a network request

Bring your own CDN

The Statsig Serverless SDK also supports a bring-your-own-CDN model. Store your Statsig config specs anywhere and initialize your client directly from that source. This model has been tested and optimized for AWS Lambda/Lambda@Edge and S3, but is compatible with any other data source. The URL you provide must return the Statsig config specs for your project.

let init = await client.initializeViaURL("https://my-statsig-config.s3.us-east-1.amazonaws.com/my_dcs.json")

After initialization, use the SDK as usual.