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    10.1.0 • Public • Published


    A Typescript Client to contact Promoted APIs. This is primarily intended to be used when logging Requests and Insertions on a Node.js server.

    Client logging libraries:


    • Demonstrates and implements the recommended practices and data types for calling Promoted's Metrics and Delivery APIs.
    • Shadow traffic and an only-log option for ramping up a Promoted integration.
    • Client-side position assignment and paging when not using results from Delivery API.

    Creating a PromotedClient

    We recommend creating a PromotedClient in a separate file so it can be reused.

    PromotedClient avoids having direct http client dependencies so customers have more options for customization and can keep dependencies smaller.

    import { logOnError, newPromotedClient, throwOnError } from 'promoted-ts-client';
    import { v5 as uuid } from 'uuid';
    // See section below.
    const apiClient = ...;
    // These values will vary depending on whether you are integrating with Promote's dev or prod environment.
    const deliveryApi = '';
    const deliveryApiKey = 'LongString1';
    const deliveryTimeoutMillis = 250;
    const metricsApi = '';
    const metricsApiKey = 'LongString2';
    const metricsTimeoutMillis = 3000;
    // NextJS example.  For errors, if inDev then throw else log.
    const throwError =
      process?.env?.NODE_ENV !== 'production' ||
      (typeof location !== "undefined" && location?.hostname === "localhost");
    export const promotedClient = newPromotedClient({
      // TODO - Customize handleError for your server.
      // When developing using Node.js, throwOnError will give a scary unhandled promise warning.
      handleError: throwError ? throwOnError : logOnError;
      deliveryClient: apiClient(deliveryApi, deliveryApiKey, deliveryTimeoutMillis),
      metricsClient: apiClient(metricsApi, metricsApiKey, metricsTimeoutMillis),

    For HTTP clients:

    • node-fetch has good latency but takes a little more work to setup. Make sure to test out the timeout logic.
    • axios is a little slower but is easier to setup.
    • got is harder to setup but provides HTTP/2 support.

    Using node-fetch

    node-fetch can be slightly faster than axios.

    import fetch from "node-fetch";
    import https from "https";
    const agent = new https.Agent({
      keepAlive: true,
      // You need to optimize this.
      maxSockets: 50,
    const apiClient = <Req, Res>(
      url: string,
      apiKey: string,
      timeoutMs: number
    ) => async (request: Req): Promise<Res> => {
      // AbortController was added in node v14.17.0 globally.
      // This can brought in as a normal import too.
      const AbortController = globalThis.AbortController || await import('abort-controller')
      const controller = new AbortController();
      const timeout = setTimeout(() => {
      }, timeoutMs);
      try {
        const response = await fetch(url, {
          method: 'POST',
          body: JSON.stringify(request),
          headers: {
            "Content-Type": "application/json",
            "Accept-Encoding": "gzip",
            "x-api-key": apiKey
          signal: controller.signal,
        return response.json();
      } finally {

    Using axios

    Axios example

    Using got

    got example

    Optimization - DNS cache

    // `szmarczak/cacheable-lookup` is owned by the same person as `got`.
    import CacheableLookup from "cacheable-lookup";
    const cacheable = new CacheableLookup({
        lookup: false,
        // TODO - review other options.

    Client Configuration Parameters

    Name Type Description
    deliveryClient ApiClient API client to make a POST request to the Delivery API endpoint including the x-api-key header, endpoint and header value obtained from Promoted
    metricsClient ApiClient API client to make a POST request to the Delivery API endpoint including the x-api-key header, endpoint and header value obtained from Promoted
    performChecks Boolean Whether or not to perform detailed input validation, defaults to true but may be disabled for performance
    shadowTrafficDeliveryRate Number between 0 and 1 % of traffic that gets directed to Delivery API as "shadow traffic". Only applies to cases where Delivery API is not called. Defaults to 0 (no shadow traffic).
    blockingShadowTraffic Boolean Option to make shadow traffic a blocking (as opposed to background) call to delivery API, defaults to False.
    defaultRequestValues BaseRequest Default values to use on every request. Only supports onlyLog setting.
    deliveryTimeoutMillis Number Timeout on the Delivery API call. Defaults to 250.
    metricsTimeoutMillis Number Timeout on the Metrics API call. Defaults to 3000.
    shouldApplyTreatment (cohortMembership: CohortMembership | undefined) => boolean Called during delivery, accepts an experiment and returns a Boolean indicating whether the request should be considered part of the control group (false) or in the treatment arm of an experiment (true). If not set, the default behavior of checking the experiement arm is applied.
    maxRequestInsertions Number Maximum number of request insertions that will be passed to Delivery API on a single request (any more will be truncated by the SDK). Defaults to 1000.

    Data Types


    Wrapper for API clients used to make Delivery and Metrics API calls to Promoted.

    export interface ApiClient<Req, Res> {
      (request: Req): Promise<Res>;


    Basic information about the request user.

    Field Name Type Optional? Description
    userId String Yes The platform user id, cleared from Promoted logs.
    logUserId String Yes A different user id (presumably a UUID) disconnected from the platform user id, good for working with unauthenticated users or implementing right-to-be-forgotten.
    isInternalUser Boolean Yes If this user is a test user or not, defaults to false.


    Assigns a user to a group. This SDK uses it to assign users to experiment groups. Useful fields for experimentation during the delivery phase.

    Field Name Type Optional? Description
    userInfo UserInfo Yes The user info structure.
    cohortId String No The experiment name.
    arm String No 'CONTROL' or one of the TREATMENT values ('TREATMENT', 'TREATMENT1', etc.).


    Properties bag. Has the structure:

      "struct": {
        "product": {
          "id": "product3",
          "title": "Product 3",
          "url": ""
          // other key-value pairs...


    Content being served at a certain position.

    Field Name Type Optional? Description
    userInfo UserInfo Yes The user info structure.
    insertionId String Yes Generated by the SDK (do not set)
    requestId String Yes Generated by the SDK when needed (do not set)
    contentId String No Identifier for the content to be ranked, must be set.
    retrievalRank Number Yes Optional original ranking of this content item.
    retrievalScore Number Yes Optional original quality score of this content item.
    properties Properties Yes Any additional custom properties to associate. For v1 integrations, it is fine not to fill in all the properties.


    User's screen dimensions.

    Field Name Type Optional? Description
    width Integer No Screen width
    height Integer No Screen height


    State of the screen including scaling.

    Field Name Type Optional? Description
    size Size Yes Screen size
    scale Float Yes Current screen scaling factor


    Alternative to user-agent strings. See

    Field Name Type Optional? Description
    isMobile Boolean Yes Mobile flag
    brand Array of ClientBrandHint Yes
    architecture String Yes
    model String Yes
    platform String Yes
    platformVersion String Yes
    uaFullVersion String Yes



    Field Name Type Optional? Description
    brand String Yes Mobile flag
    version String Yes


    Information about the user's location.

    Field Name Type Optional? Description
    latitude Float No Location latitude
    longitude Float No Location longitude
    accuracyInMeters Integer Yes Location accuracy if available


    Information about the user's browser.

    Field Name Type Optional? Description
    user_agent String Yes Browser user agent string
    viewportSize Size Yes Size of the browser viewport
    clientHints ClientHints Yes HTTP client hints structure
    referrer String Yes Request referrer


    Information about the user's device.

    Field Name Type Optional? Description
    deviceType one of (UNKNOWN_DEVICE_TYPE, DESKTOP, MOBILE, TABLET) Yes Type of device
    brand String Yes "Apple, "google", Samsung", etc.
    manufacturer String Yes "Apple", "HTC", Motorola", "HUAWEI", etc.
    identifier String Yes Android: android.os.Build.MODEL; iOS: iPhoneXX,YY, etc.
    screen Screen Yes Screen dimensions
    ipAddress String Yes Originating IP address
    location Location Yes Location information
    browser Browser Yes Browser information


    Describes a page of insertions

    Field Name Type Optional? Description
    size Number Yes Size of the page being requested
    offset Number Yes Page offset


    A request for content insertions.

    Field Name Type Optional? Description
    userInfo UserInfo Yes The user info structure.
    requestId String Yes Generated by the SDK when needed (do not set)
    useCase String Yes One of the use case enum values or strings, i.e. 'FEED', 'SEARCH', etc.
    properties Properties Yes Any additional custom properties to associate.
    paging Paging Yes Paging parameters
    device Device Yes Device information (as available)


    Input to deliver, returns ranked insertions for display.

    Field Name Type Optional? Description
    experiment CohortMembership Yes A cohort to evaluation in experimentation.
    request Request No The underlying request for content. Request insertions need to be set on request.
    onlyLog Boolean Yes Defaults to false. Set to true to log the request as the CONTROL arm of an experiment.


    Part of a ClientResponse, input to the Promoted Metrics API.

    Field Name Type Optional? Description
    request Request No The underlying request for content to log.
    insertion [] of Insertion No The insertions, which are either the original request insertions or the insertions resulting from a call to deliver if such call occurred.


    Output of deliver includes the insertions as well as a suitable LogRequest for forwarding to Metrics API.

    Field Name Type Optional? Description
    responseInsertions [] of Insertion No The insertions, which are from Delivery API (when deliver was called, i.e. we weren't either only-log or part of an experiment) or the input insertions (when the other conditions don't hold).
    logRequest LogRequest Yes A message suitable for logging to Metrics API via a follow-up call to the log() method. If a call to deliver was made (i.e. the request was not part of the CONTROL arm of an experiment or marked to only log), :logRequest will not be set, as you can assume logging was performed on the server-side by Promoted.
    clientRequestId String Yes Client-generated request id sent to Delivery API and may be useful for logging and debugging. You may fill this in yourself if you have a suitable id, otherwise the SDK will generate one.
    executionServer one of 'API' or 'SDK' Yes Indicates if response insertions on a delivery request came from the API or the SDK.


    Method Input Output Description
    deliver DeliveryRequest ClientResponse Can be used to (1) onlyLog Requests to Metrics API or (2) call Delivery API. Supports calling as shadow traffic, as an experiment or 100% launched. Clients must call ClientResponse.log() after calling deliever to log remaining records.

    Calling the Delivery API

    Let's say the previous code looks like this:

    static async getProducts(req: any, res: Response) {
      const products = ...; // Logic to get products from DB, apply filtering, etc.
      sendSuccessToClient(res, { products });

    We would modify to something like this:

     * @param userInfo { userId, logUserId, isInternalUser }
     * @return Product[].  This code will set `Product.insertionId`.
    async function callPromoted(
        products: Product[],
        userInfo: UserInfo): Promise<Product[]> {
      const responsePromise = promotedClient.deliver({
        // onlyLog: true - if you want to only log to Promoted.
        request: {
          useCase: 'FEED',
          // TODO - add `query` for the search query.
          properties: {
            struct: {
              // TODO - Add user, request and context features.
              // TODO - Add request filters.  The properties are used to generate a paging key that is used for caching.
          insertion:, retrievalRank) => ({
            properties: {
              struct: {
                // TODO - add user-item features here.
                // Example: "numReviews": product.numReviews,
        // It's okay to use Prepaged temporarily while only logging.
        insertionPageType: InsertionPageType.Unpaged,
      // Construct the map while the RPC is happening.
      const productIdToProduct = products.reduce((map, product) => {
          map[] = {...product};
          return map;
      }, {});
      const clientResponse = await responsePromise;
      // Do not block.  Log asynchronously.
      // Also adds `insertionId` field to the product.
      return toContents<Product>(

    Logging only

    You can use deliver but add a onlyLog: true property.


    • When calling deliver with onlyLog=false, we expect that you will pass an unpaged (complete) list of insertions, and the SDK assumes this to be the case. To help you catch this scenario, the SDK will call handleError in the pre-paged case if performChecks is turned on.

    • When calling deliver with onlyLog=true and shadow traffic turned on, we also expect an unpaged list of insertions, since in this case we are simulating delivery.

    • When calling deliver with onlyLog=true otherwise, you may choose to pass "pre-paged" or "unpaged" insertions based on the insertionPageType field on the MetricsRequest.

      • When insertionPageType is "unpaged", the Request.paging.offset and Request.paging.size parameters are used to log a "window" of insertions.
      • When insertionPageType is "pre-paged", the SDK will not handle pagination of the insertions that are part of the resulting lot request.


    Do not set the insertion position field in client code. The SDK and Delivery API will set it when deliver is called.

    Clients are responsible for setting retrievalRank.

    If you want to log using paginated data, you can use insertionPageType=PrePaged to log a page of data. When calling using shadow traffic or blocking to Delivery API, deliver needs as many request insertions as can be sent (probably max of 1,000).


    Promoted supports the ability to run Promoted-side experiments. Sometimes it is useful to run an experiment in your where promoted-ts-client is integrated (e.g. you want arm assignments to match your own internal experiment arm assignments).

    // Create a small config indicating the experiment is a 50-50 experiment where 10% of the users are activated.
    const experimentConfig = twoArmExperimentConfig5050("promoted-v1", 5, 5);
    async function callPromoted(
        products: Product[],
        userInfo: UserInfo): Promise<Insertion[]> {
      // This gets the anonymous user id from the request.
      const experimentMembership = twoArmExperimentMembership(userInfo.logUserId, experimentConfig);
      const responsePromise = promotedClient.deliver({
        // If experimentActivated can be false (e.g. only 5% of users get put into an experiment) and
        // you want the non-activated behavior to not call Delivery API, then you need to specify onlyLog to false.
        // This is common during ramp up.  `onlyLog` can be dropped if it's always false.
        // Example:
        // `onlyLog: experimentMembership == undefined`
        experiment: experimentMembership,
      return ...

    Here's an example using custom arm assignment logic (not using twoArmExperimentConfig5050).

    // If you already use an experiment framework, it'll have the ability to return
    // (1) if a user is activated into an experiment and
    // (2) which arm to perform.
    // [boolean, boolean]
    const [experimentActivated, inTreatment] = getExperimentActivationAndArm(experimentName, logUserId);
    // Only log if the user is activated into the experiment.
    const experimentMembership = experimentActivated
      ? {
          cohortId: experimentName,
          arm: inTreatment ? 'TREATMENT' : 'CONTROL',
      : null;

    Advanced example

    Here's a more complex example that supports:

    • Running an experiment.
    • Separate configuration for internal users.
    • Also supports skipping the experiment and only logging (or only calling Delivery API) through the same method.
     * @param userInfo { userId, logUserId, isInternalUser }
     * @param overrideOnlyLog If set, skips the experiment and forces the onlyLog option.
    async function callPromoted(
        products: Product[],
        userInfo: UserInfo,
        overrideOnlyLog : boolean | undefined): Promise<Insertion[]> {
      let onlyLog: boolean | undefined = undefined;
      let experiment: CohortMembership | undefined = undefined;
      if (overrideOnlyLog != undefined) {
        onlyLog = overrideOnlyLog;
        // Do not specify experiment when overrideOnlyLog is specified.
      } else if (userInfo.isInternalUser) {
        // Call Promoted Delivery API for internal users.
        onlyLog = false;
        // Keep experiment undefined for internal users.
      } else {
        // Normal external user for a call that should run as an experiment.
        experiment = twoArmExperimentMembership(logUserId, experimentConfig);
      const responsePromise = promotedClient.deliver({
        request: {
        insertionPageType: InsertionPageType.Unpaged,
      // Construct the map while the RPC is happening.
      const productIdToProduct = products.reduce((map, product) => {
          map[] = {...product};
          return map;
      }, {});
      const clientResponse = await responsePromise;
      // Do not block.  Log asynchronously.
      return toContents<Product>(

    Improving this library

    Tech used



    • Run most commands: npm run finish
    • Build the project: npm run build
      • Validate output bundle size with npm run size
    • Lint the project: npm run lint
    • Run unit tests: npm test or npm test

    When developing locally

    If you want to test local changes in an actual deployment, use npm link.

    1. Make sure your npm uses the same version as the client directory.
    2. Run npm run updatelink.
    3. Go to client directory and run npm link promoted-ts-client.

    When you update promoted-ts-client, run npm run updatelink.

    When you want to undo, run npm run unlink in this directory and npm unlink promoted-ts-client in the client directory.


    Based on the anticipated semantic-version, update the SERVER_VERSION constant in client.ts.

    We use a GitHub action that runs semantic-release to determine how to update versions. Just do a normal code review and this should work. Depending on the message prefixes (e.g. feat: , fix: , clean: , docs: ), it'll update the version appropriately.


    The base of this repository is a combination of the following repos:


    npm i promoted-ts-client

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