diff --git a/kotlin/src/main/com/looker/rtl/OAuthSession.kt b/kotlin/src/main/com/looker/rtl/OAuthSession.kt
index 875b37cc5..0a5e7ab6d 100644
--- a/kotlin/src/main/com/looker/rtl/OAuthSession.kt
+++ b/kotlin/src/main/com/looker/rtl/OAuthSession.kt
@@ -27,77 +27,10 @@ package com.looker.rtl
 import com.looker.sdk.AccessToken
 import java.security.MessageDigest
 import java.security.SecureRandom
-import kotlin.experimental.and
+import java.util.Base64
 
-// https://stackoverflow.com/a/52225984/74137
-// TODO performance comparison of these two methods
-@ExperimentalUnsignedTypes
-fun ByteArray.toHexStr() = asUByteArray().joinToString("") { it.toString(16).padStart(2, '0') }
-
-// Adapted from https://www.samclarke.com/kotlin-hash-strings/
-
-fun String.md5(): String {
-    return hashString(this, "MD5")
-}
-
-fun String.sha512(): String {
-    return hashString(this, "SHA-512")
-}
-
-fun String.sha256(): String {
-    return hashString(this, "SHA-256")
-}
-
-fun String.sha1(): String {
-    return hashString(this, "SHA-1")
-}
-
-fun hashString(input: ByteArray, digester: MessageDigest): String {
-    val HEX_CHARS = "0123456789abcdef"
-    val bytes = digester
-            .digest(input)
-    val result = StringBuilder(bytes.size * 2)
-
-    bytes.forEach {
-        val i = it.toInt()
-        result.append(HEX_CHARS[i shr 4 and 0x0f])
-        result.append(HEX_CHARS[i and 0x0f])
-    }
-
-    return result.toString()
-}
-
-fun hashString(input: ByteArray, type: String): String {
-    val digester = MessageDigest.getInstance(type)
-    return hashString(input, digester)
-}
-
-/**
- * Supported algorithms on Android:
- *
- * Algorithm	Supported API Levels
- * MD5          1+
- * SHA-1	    1+
- * SHA-224	    1-8,22+
- * SHA-256	    1+
- * SHA-384	    1+
- * SHA-512	    1+
- */
-fun hashString(input: String, type: String): String {
-    return hashString(input.toByteArray(), type)
-}
-
-private val hexArray = "0123456789abcdef".toCharArray()
-
-fun hexStr(bytes: ByteArray): String {
-    val hexChars = CharArray(bytes.size * 2)
-    for (j in bytes.indices) {
-        val v = (bytes[j] and 0xFF.toByte()).toInt()
-
-        hexChars[j * 2] = hexArray[v ushr 4]
-        hexChars[j * 2 + 1] = hexArray[v and 0x0F]
-    }
-    return String(hexChars)
+fun base64UrlEncode(bytes: ByteArray): String {
+    return Base64.getUrlEncoder().encodeToString(bytes)
 }
 
 @ExperimentalUnsignedTypes
@@ -142,7 +75,7 @@ class OAuthSession(override val apiSettings: ConfigurationProvider, override val
      * Generate an OAuth2 authCode request URL
      */
     fun createAuthCodeRequestUrl(scope: String, state: String): String {
-        this.codeVerifier = this.secureRandom(32).toHexStr()
+        this.codeVerifier = base64UrlEncode(this.secureRandom(32))
         val codeChallenge = this.sha256hash(this.codeVerifier)
         val config = this.apiSettings.readConfig()
         val lookerUrl = config["looker_url"]
@@ -160,14 +93,13 @@ class OAuthSession(override val apiSettings: ConfigurationProvider, override val
     fun redeemAuthCodeBody(authCode: String, codeVerifier: String? = null): Map<String, String> {
         val verifier = codeVerifier?: this.codeVerifier
         val config = this.apiSettings.readConfig()
-        val map = mapOf(
+        return mapOf(
                 "grant_type" to "authorization_code",
                 "code" to authCode,
                 "code_verifier" to verifier,
                 "client_id" to (config["client_id"] ?: error("")),
                 "redirect_uri" to (config["redirect_uri"] ?: error(""))
         )
-        return map
     }
 
     fun redeemAuthCode(authCode: String, codeVerifier: String? = null): AuthToken {
@@ -181,7 +113,8 @@ class OAuthSession(override val apiSettings: ConfigurationProvider, override val
     }
 
     fun sha256hash(value: ByteArray): String {
-        return hashString(value, messageDigest)
+        val bytes = messageDigest.digest(value)
+        return base64UrlEncode(bytes)
     }
 
     fun sha256hash(value: String): String {
diff --git a/kotlin/src/test/TestAuthSession.kt b/kotlin/src/test/TestAuthSession.kt
index fd91c8844..5da504e77 100644
--- a/kotlin/src/test/TestAuthSession.kt
+++ b/kotlin/src/test/TestAuthSession.kt
@@ -76,13 +76,9 @@ class TestAuthSession {
     @test
     fun testSha256() {
         val session = OAuthSession(settings, Transport(testSettings))
-        val rosettaCode = "Rosetta code"
-        val rosettaHash = "764faf5c61ac315f1497f9dfa542713965b785e5cc2f707d6468d7d1124cdfcf"
-        var hash = session.sha256hash(rosettaCode)
-        assertEquals(rosettaHash, hash, "Rosetta code should match")
         val message = "The quick brown fox jumped over the lazy dog."
-        hash = session.sha256hash(message)
-        assertEquals("68b1282b91de2c054c36629cb8dd447f12f096d3e3c587978dc2248444633483", hash, "Quick brown fox should match")
+        val hash = session.sha256hash(message)
+        assertEquals("aLEoK5HeLAVMNmKcuN1EfxLwltPjxYeXjcIkhERjNIM=", hash, "Quick brown fox should match")
     }
 
     @test
diff --git a/python/looker_sdk/rtl/auth_session.py b/python/looker_sdk/rtl/auth_session.py
index 7a5a1fe1c..3b733e7f4 100644
--- a/python/looker_sdk/rtl/auth_session.py
+++ b/python/looker_sdk/rtl/auth_session.py
@@ -223,7 +223,7 @@ def _ok(self, response: transport.Response) -> str:
 
 class CryptoHash:
     def secure_random(self, byte_count: int) -> str:
-        return secrets.token_hex()
+        return secrets.token_urlsafe(byte_count)
 
     def sha256_hash(self, message: str) -> str:
         value = hashlib.sha256()
diff --git a/swift/looker/Tests/lookerTests/authSessionTests.swift b/swift/looker/Tests/lookerTests/authSessionTests.swift
index 8ed912a28..2a43c5121 100644
--- a/swift/looker/Tests/lookerTests/authSessionTests.swift
+++ b/swift/looker/Tests/lookerTests/authSessionTests.swift
@@ -41,7 +41,7 @@ class authSessionTests: XCTestCase {
         let session = OAuthSession(settings, xp)
         let message = "The quick brown fox jumped over the lazy dog."
         let hash = session.sha256Hash(message)
-        XCTAssertEqual("68b1282b91de2c054c36629cb8dd447f12f096d3e3c587978dc2248444633483", hash)
+        XCTAssertEqual("aLEoK5HeLAVMNmKcuN1EfxLwltPjxYeXjcIkhERjNIM", hash)
     }
     
     func testRedemptionBody() {
diff --git a/swift/looker/Tests/lookerTests/methodsTests.swift b/swift/looker/Tests/lookerTests/methodsTests.swift
index cae4bc082..75dc22318 100644
--- a/swift/looker/Tests/lookerTests/methodsTests.swift
+++ b/swift/looker/Tests/lookerTests/methodsTests.swift
@@ -97,7 +97,7 @@ class methodsTests: XCTestCase {
         XCTAssertNotNil(me)
         _ = sdk.authSession.logout()
     }
-    
+        
     func testUserSearch() {
         let list = try? sdk.ok(sdk.search_users(
             first_name:"%",
diff --git a/swift/looker/rtl/apiConfig.swift b/swift/looker/rtl/apiConfig.swift
index c6c12ab34..47ab4e980 100644
--- a/swift/looker/rtl/apiConfig.swift
+++ b/swift/looker/rtl/apiConfig.swift
@@ -79,7 +79,7 @@ public func parseConfig(_ filename : String) -> Config {
     return config
 }
 
-public class ApiConfig: IApiSettings {
+open class ApiConfig: IApiSettings {
     public func readConfig(_ section: String? = nil) -> IApiSection {
         if (self.fileName == "") {
             // No config file to read
@@ -103,16 +103,16 @@ public class ApiConfig: IApiSettings {
     private var fileName = ""
     private var section = "Looker"
     
-    init() {
+    public init() {
         self.assign(DefaultSettings())
     }
     
-    init(_ settings: IApiSettings) {
+    public init(_ settings: IApiSettings) {
         self.assign(settings)
     }
     
     /// Get SDK settings from a configuration file with environment variable overrides
-    init(_ fileName: String = "", _ section: String = "Looker") throws {
+    public init(_ fileName: String = "", _ section: String = "Looker") throws {
         let fm = FileManager.default
         if (fileName == "") {
             // Default file name to looker.ini?
diff --git a/swift/looker/rtl/apiMethods.swift b/swift/looker/rtl/apiMethods.swift
index f3579d2bf..8af2020e8 100644
--- a/swift/looker/rtl/apiMethods.swift
+++ b/swift/looker/rtl/apiMethods.swift
@@ -29,7 +29,7 @@ open class APIMethods {
     public var authSession: IAuthorizer
     public var encoder = JSONEncoder()
     
-    init(_ authSession: IAuthorizer) {
+    public init(_ authSession: IAuthorizer) {
         self.authSession = authSession
     }
     
@@ -37,7 +37,7 @@ open class APIMethods {
         return try! encoder.encode(value)
     }
     
-    public func ok<TSuccess, TError>(_ response: SDKResponse<TSuccess, TError>) throws -> TSuccess {
+    open func ok<TSuccess, TError>(_ response: SDKResponse<TSuccess, TError>) throws -> TSuccess {
         switch response {
         case .success(let response):
             return response
@@ -53,7 +53,7 @@ open class APIMethods {
         }
     }
     
-    public func authRequest<TSuccess: Codable, TError: Codable>(
+    open func authRequest<TSuccess: Codable, TError: Codable>(
         _ method: HttpMethod,
         _ path: String,
         _ queryParams: Values?,
@@ -79,7 +79,7 @@ open class APIMethods {
     }
     
     /** Make a GET request */
-    func get<TSuccess: Codable, TError: Codable>(
+    open func get<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
@@ -95,7 +95,7 @@ open class APIMethods {
     }
     
     /** Make a HEAD request */
-    func head<TSuccess: Codable, TError: Codable>(
+    open func head<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
@@ -111,7 +111,7 @@ open class APIMethods {
     }
     
     /** Make a DELETE request */
-    func delete<TSuccess: Codable, TError: Codable>(
+    open func delete<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
@@ -127,7 +127,7 @@ open class APIMethods {
     }
     
     /** Make a POST request */
-    func post<TSuccess: Codable, TError: Codable>(
+    open func post<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
@@ -143,7 +143,7 @@ open class APIMethods {
     }
     
     /** Make a PUT request */
-    func put<TSuccess: Codable, TError: Codable>(
+    open func put<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
@@ -159,7 +159,7 @@ open class APIMethods {
     }
     
     /** Make a PATCH request */
-    func patch<TSuccess: Codable, TError: Codable>(
+    open func patch<TSuccess: Codable, TError: Codable>(
         _ path: String,
         _ queryParams: Values?,
         _ body: Any?,
diff --git a/swift/looker/rtl/apiSettings.swift b/swift/looker/rtl/apiSettings.swift
index a4a9fcd6f..a3b8794ea 100644
--- a/swift/looker/rtl/apiSettings.swift
+++ b/swift/looker/rtl/apiSettings.swift
@@ -100,9 +100,9 @@ public struct ApiSettings: IApiSettings {
     public var headers: Headers?
     public var encoding: String?
     
-    init() { }
+    public init() { }
     
-    init(_ settings: IApiSettings) throws {
+    public init(_ settings: IApiSettings) throws {
         let defaults = DefaultSettings()
         // coerce types to declared types since some paths could have non-conforming settings values
         self.base_url = unquote(settings.base_url) ?? defaults.base_url
diff --git a/swift/looker/rtl/authSession.swift b/swift/looker/rtl/authSession.swift
index 76b0ba431..bcefc75f0 100644
--- a/swift/looker/rtl/authSession.swift
+++ b/swift/looker/rtl/authSession.swift
@@ -49,7 +49,7 @@ open class AuthSession: IAuthSession {
         }
     }
     
-    init(_ settings: IApiSettings, _ transport: ITransport? = nil) {
+    public init(_ settings: IApiSettings, _ transport: ITransport? = nil) {
         self.settings = settings
         self.transport = transport ?? BaseTransport(settings)
         self.apiPath = "/api/\(settings.api_version!)"
diff --git a/swift/looker/rtl/authToken.swift b/swift/looker/rtl/authToken.swift
index d7f943614..cf61aa7c4 100644
--- a/swift/looker/rtl/authToken.swift
+++ b/swift/looker/rtl/authToken.swift
@@ -47,9 +47,9 @@ public struct AuthToken: AccessTokenProtocol, Codable {
     
     private var expiresAt: Date?
     
-    init() { }
+    public init() { }
     
-    init(_ token: AccessToken) {
+    public init(_ token: AccessToken) {
         self = self.setToken(token)
     }
     
diff --git a/swift/looker/rtl/baseTransport.swift b/swift/looker/rtl/baseTransport.swift
index ea9e32490..8df25700b 100644
--- a/swift/looker/rtl/baseTransport.swift
+++ b/swift/looker/rtl/baseTransport.swift
@@ -24,11 +24,11 @@
 
 import Foundation
 
-struct RequestResponse {
+public struct RequestResponse {
     var data: Data?
     var response: URLResponse?
     var error: SDKError?
-    init(_ data: Data?, _ response: URLResponse?, _ error: SDKError?) {
+    public init(_ data: Data?, _ response: URLResponse?, _ error: SDKError?) {
         self.data = data
         self.response = response
         self.error = error
@@ -38,18 +38,18 @@ struct RequestResponse {
 
 // some good tips here https://www.swiftbysundell.com/articles/constructing-urls-in-swift/
 @available(OSX 10.12, *)
-class BaseTransport : ITransport  {
+open class BaseTransport : ITransport  {
     public static var debugging = false
     let session = URLSession.shared // TODO Should this be something else like `configuration: .default`? or ephemeral?
     var apiPath = ""
     var options: ITransportSettings
 
-    init(_ options: ITransportSettings) {
+    public init(_ options: ITransportSettings) {
         self.options = options
         self.apiPath = "\(options.base_url!)/api/\(options.api_version!)"
     }
 
-    func request<TSuccess: Codable, TError: Codable> (
+    open func request<TSuccess: Codable, TError: Codable> (
         _ method: HttpMethod,
         _ path: String,
         _ queryParams: Values?,
@@ -71,7 +71,7 @@ class BaseTransport : ITransport  {
         return result
     }
 
-    func plainRequest(
+    open func plainRequest(
         _ method: HttpMethod,
         _ path: String,
         _ queryParams: Values?,
@@ -173,7 +173,7 @@ class BaseTransport : ITransport  {
 }
 
 @available(OSX 10.12, *)
-func processResponse<TSuccess: Codable, TError: Codable> (_ response: RequestResponse) -> SDKResponse<TSuccess,TError> {
+public func processResponse<TSuccess: Codable, TError: Codable> (_ response: RequestResponse) -> SDKResponse<TSuccess,TError> {
     if let error = response.error {
         return SDKResponse.error((error as? TError)!)
     }
diff --git a/swift/looker/rtl/oauthSession.swift b/swift/looker/rtl/oauthSession.swift
index e26cbd2f2..a7f763b69 100644
--- a/swift/looker/rtl/oauthSession.swift
+++ b/swift/looker/rtl/oauthSession.swift
@@ -25,7 +25,7 @@
 import Foundation
 import CryptoKit
 
-// from https://stackoverflow.com/a/57255549/74137
+// partly from https://stackoverflow.com/a/57255549/74137
 @available(OSX 10.15, *)
 extension Digest {
     var bytes: [UInt8] { Array(makeIterator()) }
@@ -33,9 +33,12 @@ extension Digest {
     var hexStr: String {
         bytes.map { String(format: "%02x", $0) }.joined()
     }
+    var base64Url: String {
+         data.base64Url()
+     }
 }
 
-// from https://stackoverflow.com/a/40089462/74137
+// partly from https://stackoverflow.com/a/40089462/74137
 extension Data {
     struct HexEncodingOptions: OptionSet {
         let rawValue: Int
@@ -52,17 +55,24 @@ extension Data {
         }
         return String(utf16CodeUnits: chars, count: chars.count)
     }
+    
+    func base64Url() -> String {
+        return base64EncodedString()
+            .replacingOccurrences(of: "/", with: "_")
+            .replacingOccurrences(of: "+", with: "-")
+            .replacingOccurrences(of: "=", with: "")
+    }
 }
 
 @available(OSX 10.15, *)
-class OAuthSession: AuthSession {
+open class OAuthSession: AuthSession {
     var code_verifier: String = ""
 
-    override init(_ settings: IApiSettings, _ transport: ITransport? = nil) {
+    public override init(_ settings: IApiSettings, _ transport: ITransport? = nil) {
         super.init(settings, transport)
     }
 
-    func requestToken(_ body: Values) throws -> AuthToken {
+    open func requestToken(_ body: Values) throws -> AuthToken {
         let response : SDKResponse<AccessToken, SDKError> = self.transport.request(
             HttpMethod.POST,
             "/api/token",
@@ -81,7 +91,7 @@ class OAuthSession: AuthSession {
         }
     }
 
-    override func getToken() throws -> AuthToken {
+    open override func getToken() throws -> AuthToken {
         if (!self.isAuthenticated()) {
             if (!self.activeToken.refresh_token.isEmpty) {
                 let config = self.settings.readConfig(nil)
@@ -100,8 +110,8 @@ class OAuthSession: AuthSession {
     /*
      Generate an OAuth2 authCode request URL
      */
-    func createAuthCodeRequestUrl(scope: String, state: String) throws -> String {
-        self.code_verifier = try! self.secureRandom(32).hexStr()
+    public func createAuthCodeRequestUrl(scope: String, state: String) throws -> String {
+        self.code_verifier = try! self.secureRandom(32).base64Url()
         let code_challenge = self.sha256Hash(self.code_verifier)
         let config = self.settings.readConfig(nil)
         let looker_url = config["looker_url"]!
@@ -129,7 +139,7 @@ class OAuthSession: AuthSession {
         ]
     }
 
-    func redeemAuthCode(_ authCode: String, _ code_verifier: String? = nil) throws -> AuthToken {
+    public func redeemAuthCode(_ authCode: String, _ code_verifier: String? = nil) throws -> AuthToken {
         return try self.requestToken(redeemAuthCodeBody(authCode, code_verifier))
     }
 
@@ -146,7 +156,7 @@ class OAuthSession: AuthSession {
     }
 
     public func sha256Hash(_ data: Data) -> String {
-        return SHA256.hash(data: data).hexStr
+        return SHA256.hash(data: data).base64Url
     }
 
     public func sha256Hash(_ value: String) -> String {
diff --git a/swift/looker/rtl/transport.swift b/swift/looker/rtl/transport.swift
index a985d1271..b858ec1f4 100644
--- a/swift/looker/rtl/transport.swift
+++ b/swift/looker/rtl/transport.swift
@@ -125,8 +125,8 @@ public struct SDKError: ISDKError, Codable {
     private var suggestion: String?
     private var help: String?
 
-    init() { }
-    init(_ message: String, code: Int = 0, documentation_url: String? = "", reason: String? = "", suggestion: String? = "", help: String? = "") {
+    public init() { }
+    public init(_ message: String, code: Int = 0, documentation_url: String? = "", reason: String? = "", suggestion: String? = "", help: String? = "") {
         self.code = code
         self.message = message
         self.reason = reason