Swift

Swift Personal Loans Mobile SDK Integration Guide

Overview

The Personal Loans vertical is delivered through the Engine Mobile SDK for iOS. This guide covers installation, prerequisites, the core configuration props (channel, zone, productTypes), a basic usage example, prefilling lead data, client tags, and event handlers.

You'll need the correct channel and zone values for your integration. Ask your Partner Manager to provide these values for Personal Loans.

Before you start, request an API token from your Partner Manager. It authenticates with the Engine API and is required to use the Prefill API. You may want multiple tokens depending on how many entry points your app has into the SDK.

Requirements

• Xcode 15 or higher

• iOS 15.0 or higher deployment target

• Swift 5.9 or higher

Install

Add the package via Swift Package Manager. In Xcode, select your project → Package Dependencies → “+”, enter the repository URL, then choose a version rule (Up to Next Major Version is recommended) and add the SwiftEngineSDK library to your app target. Use the latest published release — check the repository's Releases for the current version:

https://github.com/MoneyLion/engine-mobile-native-sdk.git

Because the repo is public, no GitHub account or token is required — SwiftPM downloads the binary directly.

Or add it to your Package.swift:

dependencies: [
    .package(
        url: "https://github.com/MoneyLion/engine-mobile-native-sdk.git",
        from: "1.0.0" // use the latest published release
    )
],
targets: [
    .target(
        name: "YourApp",
        dependencies: [
            .product(name: "SwiftEngineSDK", package: "engine-mobile-native-sdk")
        ]
    )
]

Initialize

Import the SDK in any file where you want to render the Engine flow:

import SwiftEngineSDK

Basic Example

EngineSDK is a UIView — construct it with its convenience initializer and add it to your view hierarchy. Use [.loan] for productTypes to render the Personal Loans flow. Your channel and zone values are provided by your Partner Manager.

let sdk = EngineSDK(
    channel: "your-channel",
    zone: "your-zone",
    productTypes: [.loan],
    onExit: { _ in
        // handle exit / navigation
    }
    // ...optional event handlers, see Event Handlers
)

view.addSubview(sdk)

Retain the EngineSDK view (e.g. as a property on your view controller or a SwiftUI coordinator). If it deallocates, the embed stops working.

Properties

Prop	Type	Required	Description
channel	String	Yes	Identifies your integration in Engine. Provided by your Partner Manager (e.g. "direct").
zone	String	Yes	Identifies the placement or distribution surface for the SDK. Provided by your Partner Manager (e.g. "marketplace").
productTypes	[ProductType]	Yes	Product flow(s) to render. ProductType is imported from the Engine SDK package — use [.loan] for Personal Loans, which maps to the string value "loan".
bearerToken	String	For prefill	API token from your Partner Manager. Required to use the Prefill API. Without it, the standard non-prefilled flow renders.
personalInformation	LeadPersonalInformation	No	Prefill data. See Prefilling Lead Data.
loanInformation	LeadLoanInformationJson	No	Prefill data. See Prefilling Lead Data.
mortgageInformation	LeadMortgageInformationJson	No	Prefill data. See Prefilling Lead Data.
creditInformation	LeadCreditInformationJson	No	Prefill data. See Prefilling Lead Data.
financialInformation	LeadFinancialInformation	No	Prefill data. See Prefilling Lead Data.
employmentInformation	LeadEmploymentInformationJson	No	Prefill data. See Prefilling Lead Data.
legalInformation	LeadLegalInformationJson	No	Prefill data. See Prefilling Lead Data.
educationInformation	LeadEducationInformationJson	No	Prefill data. See Prefilling Lead Data.
clientTags	[String: [String]]	No	Reporting/attribution tags. See Client Tags.
onExit	EngineSDKCallbacks.OnExit	Yes	Fired when the user exits the flow. Passed directly to EngineSDK(...).
onInitialize, onCreate, onUpdate, onNavigate, onSubmit, onRateTableRender, onOfferClick, onErrorPageView, onErrorPageRetry, onEmbedError, onEmbedErrorRetry	Callbacks	No	Optional tracking hooks passed to EngineSDK(...). See Event Handlers.

Prefilling Lead Data

Prefill any user data you already have to reduce what the user has to type in-flow. Prefilled data is grouped into typed information objects, each passed to EngineSDK(...) (e.g. personalInformation, loanInformation, financialInformation).

Prefilling requires a bearerToken. Pass only the fields you have — omitted fields are collected from the user in-flow.

Example

let sdk = EngineSDK(
    channel: "your-channel",
    zone: "your-zone",
    bearerToken: "{your_token}",
    productTypes: [.loan],
    personalInformation: LeadPersonalInformation(
        firstName: "Bob",
        lastName: "Dylan",
        email: "[email protected]",
        dateOfBirth: Calendar.current.date(from: DateComponents(year: 1990, month: 1, day: 1)),
        primaryPhone: "2325624852",
        address1: "1600 Pennsylvania Avenue",
        address2: "Apt 2",
        city: "Washington",
        state: .dc,
        zipcode: "20500",
        ssn: "512-54-7862"
    ),
    loanInformation: LeadLoanInformationJson(
        purpose: .creditCardRefi,
        loanAmount: 7500
    ),
    mortgageInformation: LeadMortgageInformationJson(
        propertyStatus: .ownWithMortgage
    ),
    creditInformation: LeadCreditInformationJson(
        providedCreditRating: .good
    ),
    financialInformation: LeadFinancialInformation(
        employmentStatus: .employedFullTime,
        employmentPayFrequency: .biweekly,
        annualIncome: 20000,
        bankRoutingNumber: "123456789",
        bankAccountNumber: "55555555555"
    ),
    employmentInformation: LeadEmploymentInformationJson(
        directDeposit: false
    ),
    legalInformation: LeadLegalInformationJson(
        consentsToSms: true
    ),
    educationInformation: LeadEducationInformationJson(
        educationLevel: .associate
    ),
    onExit: { _ in }
)

view.addSubview(sdk)

Type Definitions

Every prop and field is optional — pass only what you have.

struct LeadPersonalInformation {
    var firstName: String?
    var lastName: String?
    var email: String?
    var dateOfBirth: Date?
    var primaryPhone: String?   // 10 digits, no "+" or "-" chars
    var address1: String?
    var address2: String?       // optional apartment / suite
    var city: String?
    var state: State?           // 2-letter state enum (e.g. .dc)
    var zipcode: String?
    var ssn: String?            // 9 digits with or without hyphens
}

struct LeadLoanInformationJson {
    var purpose: LoanPurpose?
    var loanAmount: Int?        // whole numbers only
}

struct LeadMortgageInformationJson {
    var propertyStatus: PropertyStatus?
}

struct LeadCreditInformationJson {
    var providedCreditRating: ProvidedCreditRating?
}

struct LeadFinancialInformation {
    var employmentStatus: EmploymentStatus?
    var employmentPayFrequency: EmploymentPayFrequency?
    var annualIncome: Int?          // raw integer value (e.g. 20000)
    var bankRoutingNumber: String?  // must be exactly 9 digits
    var bankAccountNumber: String?
}

struct LeadEmploymentInformationJson {
    var directDeposit: Bool?
}

struct LeadLegalInformationJson {
    var consentsToSms: Bool?    // lead agrees to receive SMS
}

struct LeadEducationInformationJson {
    var educationLevel: EducationLevel?
}

Enums / Accepted Values

Fields backed by an enum must use a valid value.

enum LoanPurpose {
    case auto
    case autoPurchase
    case autoRefinance
    case baby
    case boat
    case business
    case carRepair
    case cosmetic
    case creditCardRefi
    case debtConsolidation
    case emergency
    case engagement
    case green
    case homeImprovement
    case homePurchase
    case homeRefi
    case householdExpenses
    case largePurchases
    case lifeEvent
    case medicalDental
    case motorcycle
    case movingRelocation
    case other
    case rv
    case specialOccasion
    case studentLoan
    case studentLoanRefi
    case taxes
    case vacation
    case wedding
}

enum ProvidedCreditRating {
    case excellent
    case good
    case fair
    case poor
    case limited
}

enum PropertyStatus {
    case ownOutright
    case ownWithMortgage
    case rent
}

enum EducationLevel {
    case highSchool
    case associate
    case bachelors
    case masters
    case doctorate
    case otherGradDegree
    case certificate
    case didNotGraduate
    case stillEnrolled
    case other
}

enum EmploymentStatus {
    case employed
    case employedFullTime
    case employedPartTime
    case military
    case notEmployed
    case selfEmployed
    case retired
    case other
}

enum EmploymentPayFrequency {
    case biweekly
    case monthly
    case twiceMonthly
    case weekly
}

// State is a 2-letter US state enum, e.g. .ca, .dc, .ny

Do not prefill any fields that are empty or unavailable — omit them so the user is prompted in-flow. Prefilled data must match the type definitions above, and any field backed by an enum must use a valid value. If a value is invalid, that attribute is stripped and the user will have to enter it again manually.

Client Tags

The Engine SDK supports adding your unique Client Tags to track performance of specific campaigns or users. All Client Tag data is attributed to the lead level.

Client Tags are added via the clientTags parameter on EngineSDK, a map of string keys to lists of string values. We strongly recommend including only one element per list for ease of reporting and attribution — if you want two separate tags, include the second tag under a different key. There is no limit to the number of keys.

let sdk = EngineSDK(
    channel: "your-channel",
    zone: "your-zone",
    bearerToken: "{your_token}",
    productTypes: [.loan],
    personalInformation: LeadPersonalInformation(/* ...any data you don't want to ask for again */),
    clientTags: [
        "clientId": ["client1"],
        "trafficsource": ["email"],
        "campaignId": ["campaign1"]
    ],
    onExit: { _ in }
)

view.addSubview(sdk)

Note: Client Tags are only sent as part of a prefill request. You must provide both a bearerToken and prefill data (via the information props such as personalInformation). If no prefill data is supplied, the SDK makes no prefill call and any clientTags you pass are ignored.

Supported Client Tag Keys for Reporting

If you plan for the Engine team to set up reporting (i.e., you do not plan to hit the Analytics API), these are the only keys that are currently fully supported. If a different key is needed, please reach out to your partner manager.

• agentId

• campaignId

• clientId

• deviceid

• medium

• sourceId

• subid

• subid1

• subid2

• subid3

• target

• trafficsource

• userid

Event Handlers

EngineSDK accepts optional callbacks that notify your app when key moments occur during the user's journey. Each callback receives an event object containing a timestamp (ISO 8601 UTC) and event-specific fields.

All callbacks are optional. Pass any combination when constructing EngineSDK. If a callback is not provided, the SDK will still log the event to the debug console in development mode.

let sdk = EngineSDK(
    channel: "your-channel",
    zone: "your-zone",
    productTypes: [.loan],
    onInitialize: { event in print("onInitialize \(event.timestamp)") },
    onCreate: { event in print("onCreate \(event.leadUuid)") },
    onSubmit: { event in print("onSubmit \(event.leadUuid)") },
    onOfferClick: { event in print("onOfferClick \(event.offerUuid)") },
    onExit: { event in
        // Navigate the user back or perform cleanup
    }
    // ...other callbacks
)

view.addSubview(sdk)

Available Events

For Personal Loans, onRateTableRender populates loanOffers and specialOffers, and onOfferClick includes loan-specific fields such as financialInstitutionName, loanAmount, apr, termLength, and monthlyPayment.

Callback	Event Type	Trigger
onInitialize	InitializeEvent	SDK finished loading the embed
onCreate	CreateEvent	New lead created
onUpdate	UpdateEvent	Lead data updated
onNavigate	NavigateEvent	Page navigation within the flow
onSubmit	SubmitEvent	Lead form submitted
onRateTableRender	RateTableRenderEvent	Rate table displayed with offers
onOfferClick	OfferClickEvent	User clicked an offer
onErrorPageView	ErrorPageViewEvent	Error page displayed in the flow
onErrorPageRetry	ErrorPageRetryEvent	User retried from the error page
onExit	ExitEvent	User exited the SDK
onEmbedError	EmbedErrorEvent	Web embed failed to load
onEmbedErrorRetry	EmbedErrorRetryEvent	User retried after embed failure

Every event includes a timestamp (ISO 8601 UTC). All fields are optional and may be null or absent. For events that vary by product (onRateTableRender and onOfferClick), each field is tagged as Common, Loan only, or Credit Card only.

onInitialize

Fired once, when the SDK finishes loading the embedded experience for the first time.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted

onCreate

Fired when a new lead is created.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the newly created lead
createPage	String	The page where the lead was created
editingPage	String	The page that the user is currently editing

onUpdate

Fired when existing lead data is updated.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the lead
updatePage	String	The page where the update occurred
editingPage	Any	The page or pages that the user is currently editing. Can be a string or a list of strings

onNavigate

Fired on page navigation within the flow.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the lead
fromPage	String	The page the user is navigating away from
toPage	String	The page the user is navigating to
editingPage	String	The page that the user is currently editing

onSubmit

Fired when the lead form is submitted.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the submitted lead

onRateTableRender

Fired when the rate table is rendered with offers. Offer objects are passed through from the embedded experience as-is.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted (Common)
rateTableUuid	String	Unique identifier for the Engine rate table (Common)
loanOffers	List	Array of loan offers returned for the lead (Loan only)
specialOffers	List	Array of special offers returned for the lead (Loan only)
creditCardOffers	List	Array of credit card offers returned for the lead (Credit Card only)

onOfferClick

Fired when the user clicks an offer in the rate table.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted (Common)
leadUuid	String	Unique identifier for the lead (Common)
offerUuid	String	Unique identifier for the clicked offer (Common)
productType	String	Type of product (e.g. "loan") (Common)
productSubType	String	Sub-type of product (Common)
financialInstitutionName	String	Name of the lending institution (Loan only)
financialInstitutionUuid	String	Unique identifier for the lending institution (Loan only)
loanAmount	Any	Loan amount offered. Can be a number or a string (Loan only)
apr	Any	Annual percentage rate. Can be a number or a string (Loan only)
termLength	Any	Length of the loan term. Can be a number or a string (Loan only)
monthlyPayment	Any	Estimated monthly payment. Can be a number or a string (Loan only)
financialInstitutionBrandName	String	Brand name of the card issuer (Credit Card only)
cardName	String	Name of the credit card (Credit Card only)
isITA	Boolean	Whether the offer is an instant-to-apply offer (Credit Card only)
cardNetwork	String	Card network (e.g. Visa, Mastercard) (Credit Card only)

onErrorPageView

Fired when the error page is displayed within the embedded flow. This is different from onEmbedError, which fires when the embedded experience itself fails to load.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the lead
fromPage	String	The page the user was on before the error
editingPage	String	The page that the user was editing

onErrorPageRetry

Fired when the user taps "Retry" on the error page within the embedded flow.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
leadUuid	String	Unique identifier for the lead
toPage	String	The page the user is retrying to navigate to
editingPage	String	The page that the user was editing

onExit

Fired when the user dismisses the SDK, either by tapping "Close" on the SDK's error screen or by exiting from within the embedded flow.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted

onEmbedError

Fired when the embedded experience fails to load (network error, or an HTTP status of 400 or above). The SDK then shows an error screen with "Retry" and "Close" options.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
errorMessage	String	Description of the error that occurred

onEmbedErrorRetry

Fired when the user taps "Retry" on the SDK's error screen after a load failure.

Field	Type	Description
timestamp	String	ISO 8601 UTC timestamp of when the event was emitted
errorMessage	String	Description of the original error that triggered the retry

Signing process

The Swift SDK's XCFramework binaries are code-signed with an Apple Distribution certificate (Apple Distribution: MoneyLion Inc) using Apple's codesign. This lets Apple and Xcode confirm that the framework was produced by Engine and has not been tampered with.

Verifying the artifact

Verification is automatic — Xcode and iOS validate the signature when the framework is integrated into your app. To check it manually:

1. Download xcframework.zip from the releases page:

https://github.com/MoneyLion/engine-mobile-native-sdk/releases

1. Extract the zip to get the .xcframework.

2. Run codesign against the framework:

codesign -dvvv <Framework>.xcframework

Confirm the output shows Authority=Apple Distribution: MoneyLion Inc.

Changelog

View the full Swift Personal Loan SDK changelog

1.0.4 (2026-10-13)

• Improve URL handling

1.0.3 (2026-09-29)

• Improve type definition

1.0.2 (2026-08-18)

• Fixed external browser behavior to ensure links open correctly in the device's default browser

1.0.1 (2026-08-04)

• Bug fixes and general improvement

1.0.0 (2026-08-03)

• Initial release of the Swift Engine SDK.