diff --git a/Sources/JSONSchema/Utilities/LockIsolated.swift b/Sources/JSONSchema/Utilities/LockIsolated.swift
new file mode 100644
index 00000000..3f3e6422
--- /dev/null
+++ b/Sources/JSONSchema/Utilities/LockIsolated.swift
@@ -0,0 +1,24 @@
+import Foundation
+
+/// A thread-safe wrapper that uses a lock to protect access to a mutable value.
+///
+/// This type provides a simple way to make a value safe to access from multiple threads
+/// by wrapping it in a lock. Access to the value is controlled through the `withLock` method.
+final class LockIsolated<Value>: @unchecked Sendable {
+  private var value: Value
+  private let lock = NSRecursiveLock()
+
+  init(_ value: @autoclosure @Sendable () throws -> Value) rethrows {
+    self.value = try value()
+  }
+
+  func withLock<T: Sendable>(
+    _ operation: @Sendable (inout Value) throws -> T
+  ) rethrows -> T {
+    lock.lock()
+    defer { lock.unlock() }
+    var value = self.value
+    defer { self.value = value }
+    return try operation(&value)
+  }
+}
diff --git a/Sources/JSONSchema/Validation/Context.swift b/Sources/JSONSchema/Validation/Context.swift
index 0127676d..e81e9eb2 100644
--- a/Sources/JSONSchema/Validation/Context.swift
+++ b/Sources/JSONSchema/Validation/Context.swift
@@ -2,24 +2,57 @@ import Foundation
 
 /// Container for information used when validating a schema.
 public final class Context: Sendable {
-  var dialect: Dialect
+  private let lockedDialect: LockIsolated<Dialect>
+  var dialect: Dialect {
+    get { lockedDialect.withLock { $0 } }
+    set { lockedDialect.withLock { $0 = newValue } }
+  }
 
-  var rootRawSchema: JSONValue?
+  private let lockedRootRawSchema: LockIsolated<JSONValue?>
+  var rootRawSchema: JSONValue? {
+    get { lockedRootRawSchema.withLock { $0 } }
+    set { lockedRootRawSchema.withLock { $0 = newValue } }
+  }
 
-  var identifierRegistry: [URL: JSONPointer] = [:]
+  private let lockedIdentifierRegistry: LockIsolated<[URL: JSONPointer]>
+  var identifierRegistry: [URL: JSONPointer] {
+    get { lockedIdentifierRegistry.withLock { $0 } }
+    set { lockedIdentifierRegistry.withLock { $0 = newValue } }
+  }
 
-  var remoteSchemaStorage: [String: JSONValue] = [:]
-  var schemaCache = [String: Schema]()
+  private let lockedRemoteSchemaStorage: LockIsolated<[String: JSONValue]>
+  var remoteSchemaStorage: [String: JSONValue] {
+    get { lockedRemoteSchemaStorage.withLock { $0 } }
+    set { lockedRemoteSchemaStorage.withLock { $0 = newValue } }
+  }
 
-  var anchors = [URL: JSONPointer]()
+  private let lockedSchemaCache: LockIsolated<[String: Schema]>
+  var schemaCache: [String: Schema] {
+    get { lockedSchemaCache.withLock { $0 } }
+    set { lockedSchemaCache.withLock { $0 = newValue } }
+  }
+
+  private let lockedAnchors: LockIsolated<[URL: JSONPointer]>
+  var anchors: [URL: JSONPointer] {
+    get { lockedAnchors.withLock { $0 } }
+    set { lockedAnchors.withLock { $0 = newValue } }
+  }
 
   /// Stack of dynamic scopes used to resolve ``$dynamicRef`` references.
   /// Each scope maps an anchor name to the schema location pointer and its
   /// associated base URI.
-  var dynamicScopes: [[String: (pointer: JSONPointer, baseURI: URL)]] = []
+  private let lockedDynamicScopes: LockIsolated<[[String: (pointer: JSONPointer, baseURI: URL)]]>
+  var dynamicScopes: [[String: (pointer: JSONPointer, baseURI: URL)]] {
+    get { lockedDynamicScopes.withLock { $0 } }
+    set { lockedDynamicScopes.withLock { $0 = newValue } }
+  }
 
   /// Validators used when the ``Keywords.Format`` keyword is present.
-  var formatValidators: [String: any FormatValidator] = [:]
+  private let lockedFormatValidators: LockIsolated<[String: any FormatValidator]>
+  var formatValidators: [String: any FormatValidator] {
+    get { lockedFormatValidators.withLock { $0 } }
+    set { lockedFormatValidators.withLock { $0 = newValue } }
+  }
 
   /// A dictionary that tracks whether the `minContains` constraint is effectively zero
   /// for specific schema locations.
@@ -30,7 +63,11 @@ public final class Context: Sendable {
   ///   at the specified schema location. A value of `true` means that the constraint
   ///   is effectively zero, allowing for validation to pass even if no instances match
   ///   the `contains` keyword.
-  var minContainsIsZero = [JSONPointer: Bool]()
+  private let lockedMinContainsIsZero: LockIsolated<[JSONPointer: Bool]>
+  var minContainsIsZero: [JSONPointer: Bool] {
+    get { lockedMinContainsIsZero.withLock { $0 } }
+    set { lockedMinContainsIsZero.withLock { $0 = newValue } }
+  }
 
   /// A dictionary that stores the results of conditional validations within a schema.
   ///
@@ -38,17 +75,28 @@ public final class Context: Sendable {
   ///   path to the "if", "else", or "then" conditions.
   /// - Value: An optional `ValidationResult` that represents the outcome of the
   ///   conditional validation at the specified schema location.
-  var ifConditionalResults = [JSONPointer: ValidationResult]()
+  private let lockedIfConditionalResults: LockIsolated<[JSONPointer: ValidationResult]>
+  var ifConditionalResults: [JSONPointer: ValidationResult] {
+    get { lockedIfConditionalResults.withLock { $0 } }
+    set { lockedIfConditionalResults.withLock { $0 = newValue } }
+  }
 
   public init(
     dialect: Dialect,
     remoteSchema: [String: JSONValue] = [:],
     formatValidators: [any FormatValidator] = []
   ) {
-    self.dialect = dialect
-    self.remoteSchemaStorage = remoteSchema
-    self.formatValidators = Dictionary(
-      uniqueKeysWithValues: formatValidators.map { ($0.formatName, $0) }
+    self.lockedDialect = LockIsolated(dialect)
+    self.lockedRootRawSchema = LockIsolated(nil)
+    self.lockedIdentifierRegistry = LockIsolated([:])
+    self.lockedRemoteSchemaStorage = LockIsolated(remoteSchema)
+    self.lockedSchemaCache = LockIsolated([:])
+    self.lockedAnchors = LockIsolated([:])
+    self.lockedDynamicScopes = LockIsolated([])
+    self.lockedFormatValidators = LockIsolated(
+      Dictionary(uniqueKeysWithValues: formatValidators.map { ($0.formatName, $0) })
     )
+    self.lockedMinContainsIsZero = LockIsolated([:])
+    self.lockedIfConditionalResults = LockIsolated([:])
   }
 }
diff --git a/Sources/JSONSchemaBuilder/Builders/JSONPropertySchemaBuilder.swift b/Sources/JSONSchemaBuilder/Builders/JSONPropertySchemaBuilder.swift
index 36c50127..c8ff8033 100644
--- a/Sources/JSONSchemaBuilder/Builders/JSONPropertySchemaBuilder.swift
+++ b/Sources/JSONSchemaBuilder/Builders/JSONPropertySchemaBuilder.swift
@@ -33,7 +33,7 @@ import JSONSchema
   }
 }
 
-public protocol PropertyCollection: Sendable {
+public protocol PropertyCollection {
   associatedtype Output
 
   var schemaValue: SchemaValue { get }
diff --git a/Sources/JSONSchemaBuilder/JSONComponent/JSONSchema.swift b/Sources/JSONSchemaBuilder/JSONComponent/JSONSchema.swift
index 794aae66..4c003446 100644
--- a/Sources/JSONSchemaBuilder/JSONComponent/JSONSchema.swift
+++ b/Sources/JSONSchemaBuilder/JSONComponent/JSONSchema.swift
@@ -8,7 +8,7 @@ public struct JSONSchema<Components: JSONSchemaComponent, NewOutput>: JSONSchema
     set { components.schemaValue = newValue }
   }
 
-  let transform: @Sendable (Components.Output) -> NewOutput
+  let transform: (Components.Output) -> NewOutput
 
   var components: Components
 
@@ -17,7 +17,7 @@ public struct JSONSchema<Components: JSONSchemaComponent, NewOutput>: JSONSchema
   ///   - transform: The transform to apply to the output.
   ///   - component: The components to group together.
   public init(
-    _ transform: @Sendable @escaping (Components.Output) -> NewOutput,
+    _ transform: @escaping (Components.Output) -> NewOutput,
     @JSONSchemaBuilder component: () -> Components
   ) {
     self.transform = transform
diff --git a/Sources/JSONSchemaBuilder/JSONComponent/JSONSchemaComponent.swift b/Sources/JSONSchemaBuilder/JSONComponent/JSONSchemaComponent.swift
index 907b6b04..bfea24cb 100644
--- a/Sources/JSONSchemaBuilder/JSONComponent/JSONSchemaComponent.swift
+++ b/Sources/JSONSchemaBuilder/JSONComponent/JSONSchemaComponent.swift
@@ -2,7 +2,7 @@ import Foundation
 import JSONSchema
 
 /// A component for use in ``JSONSchemaBuilder`` to build, annotate, and validate schemas.
-public protocol JSONSchemaComponent<Output>: Sendable {
+public protocol JSONSchemaComponent<Output> {
   associatedtype Output
 
   var schemaValue: SchemaValue { get set }
@@ -10,7 +10,7 @@ public protocol JSONSchemaComponent<Output>: Sendable {
   /// Parse a JSON instance into a Swift type using the schema.
   /// - Parameter value: The value (aka instance or document) to validate.
   /// - Returns: A validated output or error messages.
-  @Sendable func parse(_ value: JSONValue) -> Parsed<Output, ParseIssue>
+  func parse(_ value: JSONValue) -> Parsed<Output, ParseIssue>
 }
 
 extension JSONSchemaComponent {
diff --git a/Sources/JSONSchemaBuilder/JSONComponent/Modifier/AnySchemaComponent.swift b/Sources/JSONSchemaBuilder/JSONComponent/Modifier/AnySchemaComponent.swift
index bfc3375d..1a1475de 100644
--- a/Sources/JSONSchemaBuilder/JSONComponent/Modifier/AnySchemaComponent.swift
+++ b/Sources/JSONSchemaBuilder/JSONComponent/Modifier/AnySchemaComponent.swift
@@ -9,7 +9,7 @@ extension JSONSchemaComponent {
 extension JSONComponents {
   /// Component for type erasure.
   public struct AnySchemaComponent<Output>: JSONSchemaComponent {
-    private let validate: @Sendable (JSONValue) -> Parsed<Output, ParseIssue>
+    private let validate: (JSONValue) -> Parsed<Output, ParseIssue>
     public var schemaValue: SchemaValue
 
     public init<Component: JSONSchemaComponent>(_ component: Component)
diff --git a/Sources/JSONSchemaBuilder/JSONPropertyComponent/JSONPropertyComponent.swift b/Sources/JSONSchemaBuilder/JSONPropertyComponent/JSONPropertyComponent.swift
index b7cce6a3..1af24eb9 100644
--- a/Sources/JSONSchemaBuilder/JSONPropertyComponent/JSONPropertyComponent.swift
+++ b/Sources/JSONSchemaBuilder/JSONPropertyComponent/JSONPropertyComponent.swift
@@ -2,7 +2,7 @@ import JSONSchema
 
 /// A component that represents a JSON property.
 /// Used in the ``JSONObject/init(with:)`` initializer to define the properties of an object schema.
-public protocol JSONPropertyComponent: Sendable {
+public protocol JSONPropertyComponent {
   associatedtype Value: JSONSchemaComponent
   associatedtype Output