diff --git a/lib/entry-points.js b/lib/entry-points.js
index ee64cb6a5e..083567dfb2 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -29647,13 +29647,13 @@ var require_helpers = __commonJS({
     exports2.encodePath = function encodePointer(a) {
       return a.map(pathEncoder).join("");
     };
-    exports2.getDecimalPlaces = function getDecimalPlaces(number) {
+    exports2.getDecimalPlaces = function getDecimalPlaces(number2) {
       var decimalPlaces = 0;
-      if (isNaN(number)) return decimalPlaces;
-      if (typeof number !== "number") {
-        number = Number(number);
+      if (isNaN(number2)) return decimalPlaces;
+      if (typeof number2 !== "number") {
+        number2 = Number(number2);
       }
-      var parts = number.toString().split("e");
+      var parts = number2.toString().split("e");
       if (parts.length === 2) {
         if (parts[1][0] !== "-") {
           return decimalPlaces;
@@ -78733,9 +78733,9 @@ var require_enum_object = __commonJS({
       if (!isEnumObject(enumObject))
         throw new Error("not a typescript enum object");
       let values = [];
-      for (let [name, number] of Object.entries(enumObject))
-        if (typeof number == "number")
-          values.push({ name, number });
+      for (let [name, number2] of Object.entries(enumObject))
+        if (typeof number2 == "number")
+          values.push({ name, number: number2 });
       return values;
     }
     exports2.listEnumValues = listEnumValues;
@@ -92751,10 +92751,10 @@ var require_util12 = __commonJS({
       return arg == null;
     }
     exports2.isNullOrUndefined = isNullOrUndefined;
-    function isNumber(arg) {
+    function isNumber2(arg) {
       return typeof arg === "number";
     }
-    exports2.isNumber = isNumber;
+    exports2.isNumber = isNumber2;
     function isString3(arg) {
       return typeof arg === "string";
     }
@@ -101524,24 +101524,24 @@ var require_operators = __commonJS({
         }
       }.call(this);
     }
-    function toIntegerOrInfinity(number) {
-      number = Number2(number);
-      if (NumberIsNaN(number)) {
+    function toIntegerOrInfinity(number2) {
+      number2 = Number2(number2);
+      if (NumberIsNaN(number2)) {
         return 0;
       }
-      if (number < 0) {
-        throw new ERR_OUT_OF_RANGE("number", ">= 0", number);
+      if (number2 < 0) {
+        throw new ERR_OUT_OF_RANGE("number", ">= 0", number2);
       }
-      return number;
+      return number2;
     }
-    function drop(number, options = void 0) {
+    function drop(number2, options = void 0) {
       if (options != null) {
         validateObject(options, "options");
       }
       if ((options === null || options === void 0 ? void 0 : options.signal) != null) {
         validateAbortSignal(options.signal, "options.signal");
       }
-      number = toIntegerOrInfinity(number);
+      number2 = toIntegerOrInfinity(number2);
       return async function* drop2() {
         var _options$signal5;
         if (options !== null && options !== void 0 && (_options$signal5 = options.signal) !== null && _options$signal5 !== void 0 && _options$signal5.aborted) {
@@ -101552,20 +101552,20 @@ var require_operators = __commonJS({
           if (options !== null && options !== void 0 && (_options$signal6 = options.signal) !== null && _options$signal6 !== void 0 && _options$signal6.aborted) {
             throw new AbortError();
           }
-          if (number-- <= 0) {
+          if (number2-- <= 0) {
             yield val;
           }
         }
       }.call(this);
     }
-    function take(number, options = void 0) {
+    function take(number2, options = void 0) {
       if (options != null) {
         validateObject(options, "options");
       }
       if ((options === null || options === void 0 ? void 0 : options.signal) != null) {
         validateAbortSignal(options.signal, "options.signal");
       }
-      number = toIntegerOrInfinity(number);
+      number2 = toIntegerOrInfinity(number2);
       return async function* take2() {
         var _options$signal7;
         if (options !== null && options !== void 0 && (_options$signal7 = options.signal) !== null && _options$signal7 !== void 0 && _options$signal7.aborted) {
@@ -101576,10 +101576,10 @@ var require_operators = __commonJS({
           if (options !== null && options !== void 0 && (_options$signal8 = options.signal) !== null && _options$signal8 !== void 0 && _options$signal8.aborted) {
             throw new AbortError();
           }
-          if (number-- > 0) {
+          if (number2-- > 0) {
             yield val;
           }
-          if (number <= 0) {
+          if (number2 <= 0) {
             return;
           }
         }
@@ -124893,8 +124893,8 @@ var require_util16 = __commonJS({
       parts.push(format.substring(last));
       return parts.join("");
     };
-    util3.formatNumber = function(number, decimals, dec_point, thousands_sep) {
-      var n = number, c = isNaN(decimals = Math.abs(decimals)) ? 2 : decimals;
+    util3.formatNumber = function(number2, decimals, dec_point, thousands_sep) {
+      var n = number2, c = isNaN(decimals = Math.abs(decimals)) ? 2 : decimals;
       var d = dec_point === void 0 ? "," : dec_point;
       var t = thousands_sep === void 0 ? "." : thousands_sep, s = n < 0 ? "-" : "";
       var i = parseInt(n = Math.abs(+n || 0).toFixed(c), 10) + "";
@@ -144502,35 +144502,95 @@ function isArray(value) {
 function isString(value) {
   return typeof value === "string";
 }
+function isNumber(value) {
+  return typeof value === "number";
+}
 function isStringOrUndefined(value) {
   return value === void 0 || isString(value);
 }
-var string = {
-  validate: isString,
-  required: true
-};
+function defaultCheck(validate) {
+  return (arg) => ({ unknownKeys: [], invalidKeys: [], valid: validate(arg) });
+}
+function makeValidator(validate, required = true) {
+  return {
+    validate,
+    check: defaultCheck(validate),
+    required
+  };
+}
+var string = makeValidator(isString);
+var number = makeValidator(isNumber);
 function optionalOrNull(validator) {
   return {
     validate: (val) => {
       return val === void 0 || val === null || validator.validate(val);
     },
+    check: (val, opts, path29) => {
+      if (val === void 0 || val === null) {
+        return successfulCheckSchema();
+      }
+      return validator.check(val, opts, path29);
+    },
     required: false
   };
 }
 function validateSchema(schema, obj) {
+  const result = checkSchema(schema, obj, { failFast: true });
+  return result.valid;
+}
+function successfulCheckSchema() {
+  return {
+    valid: true,
+    unknownKeys: [],
+    invalidKeys: []
+  };
+}
+function checkSchema(schema, obj, options = {}, path29 = "") {
+  const result = successfulCheckSchema();
+  const inputKeys = new Set(Object.keys(obj));
+  const invalidKeys = /* @__PURE__ */ new Set();
   for (const [key, validator] of Object.entries(schema)) {
     const hasKey = key in obj;
+    inputKeys.delete(key);
+    invalidKeys.add(key);
     if (validator.required && !hasKey) {
-      return false;
+      result.valid = false;
+      if (options.failFast) {
+        break;
+      }
+      continue;
     }
     if (validator.required && (obj[key] === void 0 || obj[key] === null)) {
-      return false;
+      result.valid = false;
+      if (options.failFast) {
+        break;
+      }
+      continue;
     }
-    if (hasKey && !validator.validate(obj[key])) {
-      return false;
+    if (hasKey) {
+      const checkResult = validator.check(obj[key], options, `${path29}.${key}`);
+      result.unknownKeys.push(...checkResult.unknownKeys);
+      result.invalidKeys.push(...checkResult.invalidKeys);
+      if (checkResult.invalidKeys.length > 0) {
+        invalidKeys.delete(key);
+      }
+      if (!checkResult.valid) {
+        result.valid = false;
+        if (options.failFast) {
+          break;
+        }
+        continue;
+      }
     }
+    invalidKeys.delete(key);
   }
-  return true;
+  for (const remainingKey of inputKeys) {
+    result.unknownKeys.push(`${path29}.${remainingKey}`);
+  }
+  for (const invalidKey of invalidKeys) {
+    result.invalidKeys.push(`${path29}.${invalidKey}`);
+  }
+  return result;
 }
 
 // src/util.ts
diff --git a/src/json/index.test.ts b/src/json/index.test.ts
index eb259c757e..80edbedece 100644
--- a/src/json/index.test.ts
+++ b/src/json/index.test.ts
@@ -67,3 +67,76 @@ test("validateSchema - optional properties are optional", async (t) => {
   t.true(json.validateSchema(optionalSchema, { optionalKey: "" }));
   t.true(json.validateSchema(optionalSchema, { optionalKey: "foo" }));
 });
+
+const arraySchema = {
+  arrayKey: json.array(json.number),
+};
+
+test("validateSchema - validates arrays", async (t) => {
+  // Arrays of numeric elements are accepted.
+  t.true(json.validateSchema(arraySchema, { arrayKey: [] }));
+  t.true(json.validateSchema(arraySchema, { arrayKey: [4] }));
+  t.true(json.validateSchema(arraySchema, { arrayKey: [4, 8] }));
+  t.true(json.validateSchema(arraySchema, { arrayKey: [4, 8, 15] }));
+
+  // Other array elements are not accepted.
+  t.false(json.validateSchema(arraySchema, { arrayKey: [4, 8, 15, "bar"] }));
+  t.false(json.validateSchema(arraySchema, { arrayKey: [4, 8, undefined] }));
+  t.false(json.validateSchema(arraySchema, { arrayKey: [4, 8, 15, null] }));
+});
+
+const objectSchema = {
+  objectKey: json.object(arraySchema),
+};
+
+test("validateSchema - validates objects", async (t) => {
+  // Objects of the given schema are accepted.
+  t.true(json.validateSchema(objectSchema, { objectKey: { arrayKey: [] } }));
+  t.true(json.validateSchema(objectSchema, { objectKey: { arrayKey: [4] } }));
+
+  // Other values are not accepted.
+  t.false(json.validateSchema(objectSchema, {}));
+  t.false(json.validateSchema(objectSchema, { objectKey: [] }));
+  t.false(json.validateSchema(objectSchema, { objectKey: undefined }));
+  t.false(json.validateSchema(objectSchema, { objectKey: null }));
+  t.false(json.validateSchema(objectSchema, { objectKey: "foo" }));
+  t.false(json.validateSchema(objectSchema, { objectKey: 123 }));
+});
+
+const checkSchemaTestSchema = {
+  rootKey: json.object(objectSchema),
+};
+
+test("checkSchema - reports unknown keys", async (t) => {
+  const result = json.checkSchema(checkSchemaTestSchema, {
+    rootKey: {
+      objectKey: {
+        arrayKey: [],
+      },
+      nestedExtraKey: "foo",
+    },
+    extraKey: "bar",
+  });
+
+  t.true(result.valid);
+  t.deepEqual(
+    result.unknownKeys.sort(),
+    [".extraKey", ".rootKey.nestedExtraKey"].sort(),
+  );
+});
+
+test("checkSchema - reports invalid keys", async (t) => {
+  const result = json.checkSchema(checkSchemaTestSchema, {
+    rootKey: {
+      objectKey: {
+        arrayKey: ["foo"],
+      },
+    },
+  });
+
+  t.false(result.valid);
+  t.deepEqual(
+    result.invalidKeys.sort(),
+    [".rootKey.objectKey.arrayKey[0]"].sort(),
+  );
+});
diff --git a/src/json/index.ts b/src/json/index.ts
index a55de5b589..78923f8bac 100644
--- a/src/json/index.ts
+++ b/src/json/index.ts
@@ -48,23 +48,107 @@ export function isStringOrUndefined(
  */
 export type Validator<T> = {
   validate: (val: unknown) => val is T;
+  check: (
+    val: unknown,
+    opts: CheckSchemaOptions,
+    path: string,
+  ) => CheckSchemaResult;
   required: boolean;
 };
 
+function defaultCheck(
+  validate: (val: unknown) => val is any,
+): (arg: unknown) => CheckSchemaResult {
+  return (arg) => ({ unknownKeys: [], invalidKeys: [], valid: validate(arg) });
+}
+
+function makeValidator<T>(
+  validate: (arg: unknown) => arg is T,
+  required: boolean = true,
+) {
+  return {
+    validate,
+    check: defaultCheck(validate),
+    required,
+  } as const satisfies Validator<T>;
+}
+
 /** Extracts `T` from `Validator<T>`. */
 export type UnwrapValidator<V> = V extends Validator<infer A> ? A : never;
 
 /** A validator for string fields in schemas. */
-export const string = {
-  validate: isString,
-  required: true,
-} as const satisfies Validator<string>;
+export const string = makeValidator(isString);
 
 /** A validator for number fields in schemas. */
-export const number = {
-  validate: isNumber,
-  required: true,
-} as const satisfies Validator<number>;
+export const number = makeValidator(isNumber);
+
+/** A validator for arrays. */
+export function array<T>(validator: Validator<T>) {
+  const validate = (val: unknown) => {
+    return isArray(val) && val.every((e) => validator.validate(e));
+  };
+  return {
+    validate,
+    check: (val: unknown, opts: CheckSchemaOptions, path: string) => {
+      const result: CheckSchemaResult = successfulCheckSchema();
+
+      // The value must be an array.
+      if (!isArray(val)) {
+        result.valid = false;
+        return result;
+      }
+
+      // Validate all elements of the array.
+      let index = 0;
+      for (const e of val) {
+        const elementPath = `${path}[${index}]`;
+        const eResult = validator.check(e, opts, `${elementPath}`);
+
+        result.invalidKeys.push(...eResult.invalidKeys);
+        result.unknownKeys.push(...eResult.unknownKeys);
+        index++;
+
+        if (!eResult.valid) {
+          result.valid = false;
+
+          // Add the element path to `invalidKeys` if we didn't get
+          // any more specific ones from the element validator.
+          if (eResult.invalidKeys.length === 0) {
+            result.invalidKeys.push(elementPath);
+          }
+
+          if (opts.failFast) {
+            return result;
+          }
+
+          continue;
+        }
+      }
+
+      return result;
+    },
+    required: true,
+  } as const satisfies Validator<T[]>;
+}
+
+/** A validator for objects. */
+export function object<
+  S extends Schema,
+  T extends UnvalidatedObject<any> = FromSchema<S>,
+>(schema: S) {
+  return {
+    validate: (val: unknown) => {
+      return isObject(val) && validateSchema<S, T>(schema, val);
+    },
+    check: (val, opts, path) => {
+      if (!isObject(val)) {
+        return invalidCheckSchema();
+      }
+      return checkSchema(schema, val, opts, path);
+    },
+    required: true,
+  } as const satisfies Validator<T>;
+}
 
 /**
  * Transforms a validator to be optional, accepting `undefined` or `null` for an
@@ -75,6 +159,12 @@ export function optionalOrNull<T>(validator: Validator<T>) {
     validate: (val: unknown) => {
       return val === undefined || val === null || validator.validate(val);
     },
+    check: (val, opts, path) => {
+      if (val === undefined || val === null) {
+        return successfulCheckSchema();
+      }
+      return validator.check(val, opts, path);
+    },
     required: false,
   } as const satisfies Validator<T | undefined | null>;
 }
@@ -88,6 +178,12 @@ export function optional<T>(validator: Validator<T>) {
     validate: (val: unknown): val is T | undefined => {
       return val === undefined || validator.validate(val);
     },
+    check: (val, opts, path) => {
+      if (val === undefined) {
+        return successfulCheckSchema();
+      }
+      return validator.check(val, opts, path);
+    },
     required: false,
   } as const satisfies Validator<T | undefined>;
 }
@@ -117,28 +213,133 @@ export type FromSchema<S extends Schema> = {
  * @param obj The object to validate.
  * @returns Asserts that `obj` is of the `schema`'s type if validation is successful.
  */
-export function validateSchema<S extends Schema>(
+export function validateSchema<
+  S extends Schema,
+  T extends UnvalidatedObject<any> = FromSchema<S>,
+>(schema: S, obj: UnvalidatedObject<any>): obj is T {
+  const result = checkSchema(schema, obj, { failFast: true });
+  return result.valid;
+}
+
+export interface CheckSchemaOptions {
+  /** Whether to stop validation after the first error. */
+  failFast?: boolean;
+}
+
+export interface CheckSchemaResult {
+  /** Whether the `obj` satisfies the schema. */
+  valid: boolean;
+  /** Unknown keys that were found during validation. */
+  unknownKeys: string[];
+  /** Known keys that failed validation. */
+  invalidKeys: string[];
+}
+
+/**
+ * Convenience function to produce a `CheckSchemaResult` where `valid: true`.
+ */
+function successfulCheckSchema(): CheckSchemaResult {
+  return {
+    valid: true,
+    unknownKeys: [],
+    invalidKeys: [],
+  };
+}
+
+/**
+ * Convenience function to produce a `CheckSchemaResult` where `valid: false`.
+ */
+function invalidCheckSchema(): CheckSchemaResult {
+  return {
+    valid: false,
+    unknownKeys: [],
+    invalidKeys: [],
+  };
+}
+
+export function checkSchema<S extends Schema>(
   schema: S,
   obj: UnvalidatedObject<any>,
-): obj is FromSchema<S> {
+  options: CheckSchemaOptions = {},
+  path: string = "",
+): CheckSchemaResult {
+  const result: CheckSchemaResult = successfulCheckSchema();
+
+  // Track the set of input keys. We remove keys from this set as we recognise them
+  // during validation.
+  const inputKeys = new Set(Object.keys(obj));
+
+  // Track keys that have failed validation, starting with the empty set.
+  const invalidKeys = new Set();
+
+  // Loop through all keys in the object schema and validate that the given object
+  // satisfies the schema key.
   for (const [key, validator] of Object.entries(schema)) {
     const hasKey = key in obj;
 
+    // Remove key from set of unrecognised keys.
+    inputKeys.delete(key);
+
+    // Add the key to the set of invalid keys. We remove it later once
+    // it passes validation.
+    invalidKeys.add(key);
+
     // If the property is required, but absent, fail.
     if (validator.required && !hasKey) {
-      return false;
+      result.valid = false;
+
+      if (options.failFast) {
+        break;
+      }
+      continue;
     }
 
     // If the property is required, but undefined or null, fail.
     if (validator.required && (obj[key] === undefined || obj[key] === null)) {
-      return false;
+      result.valid = false;
+
+      if (options.failFast) {
+        break;
+      }
+      continue;
     }
 
     // If the property is present, validate it.
-    if (hasKey && !validator.validate(obj[key])) {
-      return false;
+    if (hasKey) {
+      const checkResult = validator.check(obj[key], options, `${path}.${key}`);
+
+      result.unknownKeys.push(...checkResult.unknownKeys);
+      result.invalidKeys.push(...checkResult.invalidKeys);
+
+      // If we have invalid keys from the validator, then that means that
+      // we have a more specific key than `key`. Remove `key` from the results.
+      if (checkResult.invalidKeys.length > 0) {
+        invalidKeys.delete(key);
+      }
+
+      if (!checkResult.valid) {
+        result.valid = false;
+
+        if (options.failFast) {
+          break;
+        }
+        continue;
+      }
     }
+
+    // If we reach this point, the key has been successfully validated.
+    invalidKeys.delete(key);
+  }
+
+  // If there are any remaining keys in `inputKeys`, add them to `unknownKeys`.
+  for (const remainingKey of inputKeys) {
+    result.unknownKeys.push(`${path}.${remainingKey}`);
+  }
+
+  // If there are any remaining keys in `invalidKeys`, add them to the result.
+  for (const invalidKey of invalidKeys) {
+    result.invalidKeys.push(`${path}.${invalidKey}`);
   }
 
-  return true;
+  return result;
 }