diff --git a/Sources/Hub/Hub.swift b/Sources/Hub/Hub.swift
index c5649ce..8789ebd 100644
--- a/Sources/Hub/Hub.swift
+++ b/Sources/Hub/Hub.swift
@@ -112,9 +112,12 @@ public class LanguageModelConfigurationFromHub {
 
     private var configPromise: Task<Configurations, Error>? = nil
 
-    public init(modelName: String) {
+    public init(
+        modelName: String,
+        hubApi: HubApi = .shared
+    ) {
         self.configPromise = Task.init {
-            return try await self.loadConfig(modelName: modelName)
+            return try await self.loadConfig(modelName: modelName, hubApi: hubApi)
         }
     }
 
@@ -161,8 +164,10 @@ public class LanguageModelConfigurationFromHub {
         }
     }
 
-    func loadConfig(modelName: String, hfToken: String? = nil) async throws -> Configurations {
-        let hubApi = HubApi(hfToken: hfToken)
+    func loadConfig(
+        modelName: String,
+        hubApi: HubApi = .shared
+    ) async throws -> Configurations {
         let filesToDownload = ["config.json", "tokenizer_config.json", "tokenizer.json"]
         let repo = Hub.Repo(id: modelName)
         try await hubApi.snapshot(from: repo, matching: filesToDownload)
@@ -172,7 +177,11 @@ public class LanguageModelConfigurationFromHub {
         let tokenizerConfig = try? hubApi.configuration(from: "tokenizer_config.json", in: repo)
         let tokenizerVocab = try hubApi.configuration(from: "tokenizer.json", in: repo)
         
-        let configs = Configurations(modelConfig: modelConfig, tokenizerConfig: tokenizerConfig, tokenizerData: tokenizerVocab)
+        let configs = Configurations(
+            modelConfig: modelConfig,
+            tokenizerConfig: tokenizerConfig,
+            tokenizerData: tokenizerVocab
+        )
         return configs
     }
 
diff --git a/Sources/Hub/HubApi.swift b/Sources/Hub/HubApi.swift
index da51cc8..edce7ba 100644
--- a/Sources/Hub/HubApi.swift
+++ b/Sources/Hub/HubApi.swift
@@ -8,25 +8,29 @@
 import Foundation
 
 public struct HubApi {
-    var downloadBase: URL
-    var hfToken: String?
-    var endpoint: String
+    public let downloadBase: URL
+    public let hfToken: String?
+    public let endpoint: String
     
     public typealias RepoType = Hub.RepoType
     public typealias Repo = Hub.Repo
     
-    public init(downloadBase: URL? = nil, hfToken: String? = nil, endpoint: String = "https://huggingface.co") {
-        if downloadBase == nil {
+    public init(
+        downloadBase: URL? = nil,
+        hfToken: String? = nil,
+        endpoint: String = "https://huggingface.co"
+    ) {
+        self.hfToken = hfToken
+        if let downloadBase {
+            self.downloadBase = downloadBase
+        } else {
             let documents = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
             self.downloadBase = documents.appending(component: "huggingface")
-        } else {
-            self.downloadBase = downloadBase!
         }
-        self.hfToken = hfToken
         self.endpoint = endpoint
     }
     
-    static let shared = HubApi()
+    public static let shared = HubApi()
 }
 
 /// File retrieval
@@ -179,7 +183,13 @@ public extension HubApi {
         let repoDestination = localRepoLocation(repo)
         for filename in filenames {
             let fileProgress = Progress(totalUnitCount: 100, parent: progress, pendingUnitCount: 1)
-            let downloader = HubFileDownloader(repo: repo, repoDestination: repoDestination, relativeFilename: filename, hfToken: hfToken, endpoint: endpoint)
+            let downloader = HubFileDownloader(
+                repo: repo,
+                repoDestination: repoDestination,
+                relativeFilename: filename,
+                hfToken: hfToken,
+                endpoint: endpoint
+            )
             try await downloader.download { fractionDownloaded in
                 fileProgress.completedUnitCount = Int64(100 * fractionDownloaded)
                 progressHandler(progress)
diff --git a/Sources/Tokenizers/Tokenizer.swift b/Sources/Tokenizers/Tokenizer.swift
index 300ed2a..093c212 100644
--- a/Sources/Tokenizers/Tokenizer.swift
+++ b/Sources/Tokenizers/Tokenizer.swift
@@ -234,8 +234,11 @@ extension AutoTokenizer {
         return try PreTrainedTokenizer(tokenizerConfig: tokenizerConfig, tokenizerData: tokenizerData)
     }
 
-    public static func from(pretrained model: String) async throws -> Tokenizer {
-        let config = LanguageModelConfigurationFromHub(modelName: model)
+    public static func from(
+        pretrained model: String,
+        hubApi: HubApi = .shared
+    ) async throws -> Tokenizer {
+        let config = LanguageModelConfigurationFromHub(modelName: model, hubApi: hubApi)
         guard let tokenizerConfig = try await config.tokenizerConfig else { throw TokenizerError.missingConfig }
         let tokenizerData = try await config.tokenizerData