diff --git a/Sources/TwigsCore/Budget.swift b/Sources/TwigsCore/Budget.swift
index 18f6c65..82d551b 100644
--- a/Sources/TwigsCore/Budget.swift
+++ b/Sources/TwigsCore/Budget.swift
@@ -5,15 +5,31 @@ public struct Budget: Identifiable, Hashable, Codable {
     public let name: String
     public let description: String?
     public let currencyCode: String?
+
+    public init(id: String, name: String, description: String?, currencyCode: String?) {
+        self.id = id
+        self.name = name
+        self.description = description
+        self.currencyCode = currencyCode
+    }
 }
 
-public struct BudgetOverview {
+public struct BudgetOverview: Equatable {
     public let budget: Budget
     public let balance: Int
-    public var expectedIncome: Int = 0
-    public var actualIncome: Int = 0
-    public var expectedExpenses: Int = 0
-    public var actualExpenses: Int = 0
+    public var expectedIncome: Int
+    public var actualIncome: Int
+    public var expectedExpenses: Int
+    public var actualExpenses: Int
+    
+    public init(budget: Budget, balance: Int, expectedIncome: Int = 0, actualIncome: Int = 0, expectedExpenses: Int = 0, actualExpenses: Int = 0) {
+        self.budget = budget
+        self.balance = balance
+        self.expectedIncome = expectedIncome
+        self.actualIncome = actualIncome
+        self.expectedExpenses = expectedExpenses
+        self.actualExpenses = actualExpenses
+    }
 }
 
 public protocol BudgetRepository {
diff --git a/Sources/TwigsCore/Category.swift b/Sources/TwigsCore/Category.swift
index 0cd8dbf..143b4be 100644
--- a/Sources/TwigsCore/Category.swift
+++ b/Sources/TwigsCore/Category.swift
@@ -8,6 +8,38 @@ public struct Category: Identifiable, Hashable, Codable {
     public let amount: Int
     public let expense: Bool
     public let archived: Bool
+    
+    public init(
+        budgetId: String,
+        id: String = "",
+        title: String = "",
+        description: String? = "",
+        amount: Int = 0,
+        expense: Bool = true,
+        archived: Bool = false
+    ) {
+        self.budgetId = budgetId
+        self.id = id
+        self.title = title
+        self.description = description
+        self.amount = amount
+        self.expense = expense
+        self.archived = archived
+    }
+}
+
+extension Category {
+    public var type: TransactionType {
+        if (self.expense) {
+            return .expense
+        } else {
+            return .income
+        }
+    }
+
+    public var amountString: String {
+        return self.amount > 0 ? String(format: "%.02d", Double(self.amount) / 100.0) : ""
+    }
 }
 
 public protocol CategoryRepository {
diff --git a/Sources/TwigsCore/RecurringTransaction.swift b/Sources/TwigsCore/RecurringTransaction.swift
index 6a4d8f1..9723df9 100644
--- a/Sources/TwigsCore/RecurringTransaction.swift
+++ b/Sources/TwigsCore/RecurringTransaction.swift
@@ -13,12 +13,52 @@ public struct RecurringTransaction: Identifiable, Hashable, Codable {
     public let description: String?
     public let frequency: Frequency
     public let start: Date
-    public let end: Date?
+    public let finish: Date?
     public let amount: Int
     public let categoryId: String?
     public let expense: Bool
     public let createdBy: String
     public let budgetId: String
+    
+    public init(
+        id: String = "",
+        title: String = "",
+        description: String? = nil,
+        frequency: Frequency = Frequency(unit: FrequencyUnit.daily, count: 1, time: Time(hours: 9, minutes: 0, seconds: 0)!)!,
+        start: Date = Date(),
+        finish: Date? = nil,
+        amount: Int = 0,
+        categoryId: String? = nil,
+        expense: Bool = true,
+        createdBy: String,
+        budgetId: String
+    ) {
+        self.id = id
+        self.title = title
+        self.description = description
+        self.frequency = frequency
+        self.start = start
+        self.finish = finish
+        self.amount = amount
+        self.categoryId = categoryId
+        self.expense = expense
+        self.createdBy = createdBy
+        self.budgetId = budgetId
+    }
+}
+
+extension RecurringTransaction {
+    public var type: TransactionType {
+        if (self.expense) {
+            return .expense
+        } else {
+            return .income
+        }
+    }
+    
+    public var amountString: String {
+        return self.amount > 0 ? String(format: "%.02f", Double(self.amount) / 100.0) : ""
+    }
 }
 
 public struct Frequency: Hashable, Codable, CustomStringConvertible {
@@ -100,7 +140,18 @@ public struct Frequency: Hashable, Codable, CustomStringConvertible {
     }
 }
 
-public enum FrequencyUnit: Hashable, CustomStringConvertible {
+public enum FrequencyUnit: Identifiable, Hashable, CustomStringConvertible, CaseIterable {
+    public var id: String {
+        return self.baseName
+    }
+    
+    public static var allCases: [FrequencyUnit] = [
+        .daily,
+        .weekly(Set()),
+        .monthly(.fixed(1)),
+        .yearly(DayOfYear(month: 1, day: 1)!),
+    ]
+    
     case daily
     case weekly(Set<DayOfWeek>)
     case monthly(DayOfMonth)
@@ -111,11 +162,11 @@ public enum FrequencyUnit: Hashable, CustomStringConvertible {
         case .daily:
             return "D"
         case .weekly(let daysOfWeek):
-            return String(format: "W;%s", daysOfWeek.map { $0.rawValue }.joined(separator: ","))
+            return "W;\(daysOfWeek.map { $0.rawValue }.joined(separator: ","))"
         case .monthly(let dayOfMonth):
-            return String(format: "M;%s", dayOfMonth.description)
+            return "M;\(dayOfMonth.description)"
         case .yearly(let dayOfYear):
-            return String(format: "Y;%s", dayOfYear.description)
+            return "Y;\(dayOfYear.description)"
         }
     }
     
@@ -131,6 +182,19 @@ public enum FrequencyUnit: Hashable, CustomStringConvertible {
             return String(localized: "Every \(count) year(s) on \(dayOfYear.description) at \(time.description)")
         }
     }
+    
+    public var baseName: String {
+        switch self {
+        case .daily:
+            return "day"
+        case .weekly(_):
+            return "week"
+        case .monthly(_):
+            return "month"
+        case .yearly(_):
+            return "year"
+        }
+    }
 }
 
 public struct Time: Hashable, CustomStringConvertible {
@@ -169,13 +233,13 @@ public struct Time: Hashable, CustomStringConvertible {
 }
 
 public enum DayOfMonth: Hashable, CustomStringConvertible {
-    case positional(Position, DayOfWeek)
+    case ordinal(Ordinal, DayOfWeek)
     case fixed(Int)
-    public init?(position: Position, dayOfWeek: DayOfWeek) {
-        if position == .day {
+    public init?(ordinal: Ordinal, dayOfWeek: DayOfWeek) {
+        if ordinal == .day {
             return nil
         }
-        self = .positional(position, dayOfWeek)
+        self = .ordinal(ordinal, dayOfWeek)
     }
     
     public init?(day: Int) {
@@ -187,7 +251,7 @@ public enum DayOfMonth: Hashable, CustomStringConvertible {
     
     public init?(from string: String) {
         let parts = string.split(separator: "-")
-        guard let position = Position.init(rawValue: String(parts[0])) else {
+        guard let position = Ordinal.init(rawValue: String(parts[0])) else {
             return nil
         }
         if position == .day {
@@ -199,21 +263,21 @@ public enum DayOfMonth: Hashable, CustomStringConvertible {
             guard let dayOfWeek = DayOfWeek(rawValue: String(parts[1])) else {
                 return nil
             }
-            self = .positional(position, dayOfWeek)
+            self = .ordinal(position, dayOfWeek)
         }
     }
     
     public var description: String {
         switch self {
-        case .positional(let position, let dayOfWeek):
-            return "\(position)-\(dayOfWeek)"
+        case .ordinal(let position, let dayOfWeek):
+            return "\(position.rawValue)-\(dayOfWeek)"
         case .fixed(let day):
-            return "\(Position.day)-\(day)"
+            return "\(Ordinal.day.rawValue)-\(day)"
         }
     }
 }
 
-public enum Position: String, Hashable {
+public enum Ordinal: String, Hashable, CaseIterable {
     case day = "DAY"
     case first = "FIRST"
     case second = "SECOND"
@@ -222,14 +286,18 @@ public enum Position: String, Hashable {
     case last = "LAST"
 }
 
-public enum DayOfWeek: String, Hashable {
+public enum DayOfWeek: String, Hashable, CaseIterable, Identifiable {
+    public var id: String {
+        return self.rawValue
+    }
+    
+    case sunday = "SUNDAY"
     case monday = "MONDAY"
     case tuesday = "TUESDAY"
     case wednesday = "WEDNESDAY"
     case thursday = "THURSDAY"
     case friday = "FRIDAY"
     case saturday = "SATURDAY"
-    case sunday = "SUNDAY"
 }
 
 public struct DayOfYear: Hashable, CustomStringConvertible {
@@ -237,17 +305,7 @@ public struct DayOfYear: Hashable, CustomStringConvertible {
     public let day: Int
     
     public init?(month: Int, day: Int) {
-        var maxDay: Int
-        switch month {
-        case 2:
-            maxDay = 29;
-            break;
-        case 4, 6, 9, 11:
-            maxDay = 30;
-            break;
-        default:
-            maxDay = 31;
-        }
+        let maxDay = DayOfYear.maxDays(inMonth: month)
         if day < 1 || day > maxDay {
             return nil
         }
@@ -271,10 +329,21 @@ public struct DayOfYear: Hashable, CustomStringConvertible {
     public var description: String {
         return String(format: "%02d-%02d", self.month, self.day)
     }
+    
+    public static func maxDays(inMonth month: Int) -> Int {
+        switch month {
+        case 2:
+            return 29;
+        case 4, 6, 9, 11:
+            return 30;
+        default:
+            return 31;
+        }
+    }
 }
 
 public protocol RecurringTransactionsRepository {
-    func getRecurringTransactions(budgetId: String) async throws -> [RecurringTransaction]
+    func getRecurringTransactions(_ budgetId: String) async throws -> [RecurringTransaction]
     func getRecurringTransaction(_ id: String) async throws -> RecurringTransaction
     func createRecurringTransaction(_ transaction: RecurringTransaction) async throws -> RecurringTransaction
     func updateRecurringTransaction(_ transaction: RecurringTransaction) async throws -> RecurringTransaction
diff --git a/Sources/TwigsCore/Transaction.swift b/Sources/TwigsCore/Transaction.swift
index 4d60357..b5bedbf 100644
--- a/Sources/TwigsCore/Transaction.swift
+++ b/Sources/TwigsCore/Transaction.swift
@@ -17,10 +17,26 @@ public struct Transaction: Identifiable, Hashable, Codable {
     public let expense: Bool
     public let createdBy: String
     public let budgetId: String
+    
+    public init(id: String = "", title: String = "", description: String? = "", date: Date = Date(), amount: Int = 0, categoryId: String? = "", expense: Bool = true, createdBy: String, budgetId: String) {
+        self.id = id
+        self.title = title
+        self.description = description
+        self.date = date
+        self.amount = amount
+        self.categoryId = categoryId
+        self.expense = expense
+        self.createdBy = createdBy
+        self.budgetId = budgetId
+    }
 }
 
 public struct BalanceResponse: Codable {
     public let balance: Int
+
+    public init(balance: Int) {
+        self.balance = balance
+    }
 }
 
 public enum TransactionType: Int, CaseIterable, Identifiable, Hashable {
@@ -40,7 +56,7 @@ extension Transaction {
     }
     
     public var amountString: String {
-        return String(Double(self.amount) / 100.0)
+        return self.amount > 0 ? String(format: "%.02d", Double(self.amount) / 100.0) : ""
     }
 }
 
diff --git a/Sources/TwigsCore/TwigsApiService.swift b/Sources/TwigsCore/TwigsApiService.swift
index 126be23..d7ebeab 100644
--- a/Sources/TwigsCore/TwigsApiService.swift
+++ b/Sources/TwigsCore/TwigsApiService.swift
@@ -14,7 +14,7 @@ open class TwigsApiService: BudgetRepository, CategoryRepository, RecurringTrans
         self.init(RequestHelper())
     }
     
-    init(_ requestHelper: RequestHelper) {
+    public init(_ requestHelper: RequestHelper) {
         self.requestHelper = requestHelper
     }
     
@@ -221,7 +221,7 @@ open class TwigsApiService: BudgetRepository, CategoryRepository, RecurringTrans
     }
     
     // MARK: Recurring Transactions
-    open func getRecurringTransactions(budgetId: String) async throws -> [RecurringTransaction] {
+    open func getRecurringTransactions(_ budgetId: String) async throws -> [RecurringTransaction] {
         return try await requestHelper.get("/api/recurringtransactions", queries: ["budgetId": [budgetId]])
     }
     
@@ -242,26 +242,26 @@ open class TwigsApiService: BudgetRepository, CategoryRepository, RecurringTrans
     }
 }
 
-class RequestHelper {
+public class RequestHelper {
     let decoder = JSONDecoder()
     private var _baseUrl: String? = nil
     var baseUrl: String? {
         get {
-            self.baseUrl
+            self._baseUrl
         }
         set {
             guard var correctServer = newValue?.lowercased() else {
                 return
             }
             if !correctServer.starts(with: "http://") && !correctServer.starts(with: "https://") {
-                correctServer = "http://\(correctServer)"
+                correctServer = "https://\(correctServer)"
             }
             self._baseUrl = correctServer
         }
     }
     var token: String?
     
-    init() {
+    public init() {
         self.decoder.dateDecodingStrategy = .formatted(Date.iso8601DateFormatter)
     }
     
@@ -317,11 +317,14 @@ class RequestHelper {
         var request = URLRequest(url: url)
         request.addValue("application/json", forHTTPHeaderField: "Content-Type")
         request.httpMethod = "DELETE"
+        if let token = self.token {
+            request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
+        }
         
         let (_, res) = try await URLSession.shared.data(for: request)
         guard let response = res as? HTTPURLResponse, 200...299 ~= response.statusCode else {
             switch (res as? HTTPURLResponse)?.statusCode {
-            case 400: throw NetworkError.badRequest
+            case 400: throw NetworkError.badRequest(nil)
             case 401, 403: throw NetworkError.unauthorized
             case 404: throw NetworkError.notFound
             default: throw NetworkError.unknown
@@ -351,16 +354,46 @@ class RequestHelper {
             request.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
         }
         
-        let (data, res) = try await URLSession.shared.data(for: request)
-        guard let response = res as? HTTPURLResponse, 200...299 ~= response.statusCode else {
-            switch (res as? HTTPURLResponse)?.statusCode {
-            case 400: throw NetworkError.badRequest
+        var data: Data? = nil
+        var res: URLResponse?
+        do {
+            (data, res) = try await URLSession.shared.data(for: request)
+            guard let response = res as? HTTPURLResponse, 200...299 ~= response.statusCode else {
+                switch (res as? HTTPURLResponse)?.statusCode ?? -1 {
+                case 400:
+                    var reason: String? = nil
+                    if let data = data {
+                        reason = String(decoding: data, as: UTF8.self)
+                    }
+                    throw NetworkError.badRequest(reason)
+                case 401, 403: throw NetworkError.unauthorized
+                case 404: throw NetworkError.notFound
+                case 500...599: throw NetworkError.server
+                default: throw NetworkError.unknown
+                }
+            }
+        } catch {
+            switch (res as? HTTPURLResponse)?.statusCode ?? -1 {
             case 401, 403: throw NetworkError.unauthorized
             case 404: throw NetworkError.notFound
-            default: throw NetworkError.unknown
+            case 500...599: throw NetworkError.server
+            default:
+                var reason: String = error.localizedDescription
+                if let data = data {
+                    reason = String(decoding: data, as: UTF8.self)
+                }
+                throw NetworkError.badRequest(reason)
             }
         }
-        return try self.decoder.decode(ResultType.self, from: data)
+        do {
+            guard let data = data else {
+                throw NetworkError.unknown
+            }
+            return try self.decoder.decode(ResultType.self, from: data)
+        } catch {
+            print("error decoding json: \(error)")
+            throw NetworkError.jsonParsingFailed(error)
+        }
     }
 }
 
@@ -373,10 +406,12 @@ public enum NetworkError: Error, Equatable {
             return true
         case (.unauthorized, .unauthorized):
             return true
-        case (.badRequest, .badRequest):
-            return true
+        case (let .badRequest(reason1), let .badRequest(reason2)):
+            return reason1 == reason2
         case (.invalidUrl, .invalidUrl):
             return true
+        case (.server, .server):
+            return true
         case (let .jsonParsingFailed(error1), let .jsonParsingFailed(error2)):
             return error1.localizedDescription == error2.localizedDescription
         default:
@@ -395,10 +430,12 @@ public enum NetworkError: Error, Equatable {
                 return "deleted"
             case .unauthorized:
                 return "unauthorized"
-            case .badRequest:
+            case .badRequest(_):
                 return "badRequest"
             case .invalidUrl:
                 return "invalidUrl"
+            case .server:
+                return "server"
             case .jsonParsingFailed(_):
                 return "jsonParsingFailed"
             }
@@ -409,8 +446,9 @@ public enum NetworkError: Error, Equatable {
     case notFound
     case deleted
     case unauthorized
-    case badRequest
+    case badRequest(String?)
     case invalidUrl
+    case server
     case jsonParsingFailed(Error)
 }
 
diff --git a/Sources/TwigsCore/User.swift b/Sources/TwigsCore/User.swift
index 9eb61b2..65f096d 100644
--- a/Sources/TwigsCore/User.swift
+++ b/Sources/TwigsCore/User.swift
@@ -10,25 +10,66 @@ import Foundation
 public struct User: Codable, Equatable, Hashable {
     public let id: String
     public let username: String
+    public let password: String?
     public let email: String?
     public let avatar: String?
+    
+    public init(id: String, username: String, email: String?, password: String?, avatar: String?) {
+        self.id = id
+        self.username = username
+        self.email = email
+        self.password = password
+        self.avatar = avatar
+    }
+    
+    public func copy(
+        username: String? = nil,
+        email: String? = nil,
+        password: String? = nil,
+        avatar: String? = nil
+    ) -> User {
+        return User(
+            id: self.id,
+            username: username ?? self.username,
+            email: email ?? self.email,
+            password: password ?? self.password,
+            avatar: avatar ?? self.avatar
+        )
+    }
 }
 
 public struct LoginRequest: Codable {
     public let username: String
     public let password: String
+
+    public init(username: String, password: String) {
+        self.username = username
+        self.password = password
+    }
 }
 
 public struct LoginResponse: Codable {
     public let token: String
     public let expiration: String
     public let userId: String
+    
+    public init(token: String, expiration: String, userId: String) {
+        self.token = token
+        self.expiration = expiration
+        self.userId = userId
+    }
 }
 
 public struct RegistrationRequest: Codable {
     public let username: String
     public let email: String
     public let password: String
+    
+    public init(username: String, email: String, password: String) {
+        self.username = username
+        self.email = email
+        self.password = password
+    }
 }
 
 public protocol UserRepository {