diff --git a/.changeset/lets-go-travel.md b/.changeset/lets-go-travel.md
new file mode 100644
index 00000000000..1731f975ff3
--- /dev/null
+++ b/.changeset/lets-go-travel.md
@@ -0,0 +1,5 @@
+---
+"@firebase/util": major
+---
+
+Internal changes to validation APIs.
diff --git a/packages/database/src/api/Reference.ts b/packages/database/src/api/Reference.ts
index d5862154df3..e918b3020f9 100644
--- a/packages/database/src/api/Reference.ts
+++ b/packages/database/src/api/Reference.ts
@@ -123,30 +123,27 @@ export class DataSnapshot implements Compat<ExpDataSnapshot> {
   /**
    * Returns a DataSnapshot of the specified child node's contents.
    *
-   * @param childPathString Path to a child.
+   * @param path Path to a child.
    * @return DataSnapshot for child node.
    */
-  child(childPathString: string): DataSnapshot {
+  child(path: string): DataSnapshot {
     validateArgCount('DataSnapshot.child', 0, 1, arguments.length);
     // Ensure the childPath is a string (can be a number)
-    childPathString = String(childPathString);
-    validatePathString('DataSnapshot.child', 1, childPathString, false);
-    return new DataSnapshot(
-      this._database,
-      this._delegate.child(childPathString)
-    );
+    path = String(path);
+    validatePathString('DataSnapshot.child', 'path', path, false);
+    return new DataSnapshot(this._database, this._delegate.child(path));
   }
 
   /**
    * Returns whether the snapshot contains a child at the specified path.
    *
-   * @param childPathString Path to a child.
+   * @param path Path to a child.
    * @return Whether the child exists.
    */
-  hasChild(childPathString: string): boolean {
+  hasChild(path: string): boolean {
     validateArgCount('DataSnapshot.hasChild', 1, 1, arguments.length);
-    validatePathString('DataSnapshot.hasChild', 1, childPathString, false);
-    return this._delegate.hasChild(childPathString);
+    validatePathString('DataSnapshot.hasChild', 'path', path, false);
+    return this._delegate.hasChild(path);
   }
 
   /**
@@ -169,7 +166,7 @@ export class DataSnapshot implements Compat<ExpDataSnapshot> {
    */
   forEach(action: (snapshot: DataSnapshot) => boolean | void): boolean {
     validateArgCount('DataSnapshot.forEach', 1, 1, arguments.length);
-    validateCallback('DataSnapshot.forEach', 1, action, false);
+    validateCallback('DataSnapshot.forEach', 'action', action, false);
     return this._delegate.forEach(expDataSnapshot =>
       action(new DataSnapshot(this._database, expDataSnapshot))
     );
@@ -231,7 +228,7 @@ export class Query implements Compat<QueryImpl> {
     context?: object | null
   ): SnapshotCallback {
     validateArgCount('Query.on', 2, 4, arguments.length);
-    validateCallback('Query.on', 2, callback, false);
+    validateCallback('Query.on', 'callback', callback, false);
 
     const ret = Query.getCancelAndContextArgs_(
       'Query.on',
@@ -267,7 +264,7 @@ export class Query implements Compat<QueryImpl> {
         return callback;
       default:
         throw new Error(
-          errorPrefix('Query.on', 1, false) +
+          errorPrefix('Query.on', 'eventType') +
             'must be a valid event type = "value", "child_added", "child_removed", ' +
             '"child_changed", or "child_moved".'
         );
@@ -280,9 +277,9 @@ export class Query implements Compat<QueryImpl> {
     context?: object | null
   ): void {
     validateArgCount('Query.off', 0, 3, arguments.length);
-    validateEventType('Query.off', 1, eventType, true);
-    validateCallback('Query.off', 2, callback, true);
-    validateContextObject('Query.off', 3, context, true);
+    validateEventType('Query.off', eventType, true);
+    validateCallback('Query.off', 'callback', callback, true);
+    validateContextObject('Query.off', 'context', context, true);
     if (callback) {
       const valueCallback: UserCallback = () => {};
       valueCallback.userCallback = callback;
@@ -307,12 +304,12 @@ export class Query implements Compat<QueryImpl> {
    */
   once(
     eventType: string,
-    userCallback?: SnapshotCallback,
+    callback?: SnapshotCallback,
     failureCallbackOrContext?: ((a: Error) => void) | object | null,
     context?: object | null
   ): Promise<DataSnapshot> {
     validateArgCount('Query.once', 1, 4, arguments.length);
-    validateCallback('Query.once', 2, userCallback, true);
+    validateCallback('Query.once', 'callback', callback, true);
 
     const ret = Query.getCancelAndContextArgs_(
       'Query.on',
@@ -322,12 +319,12 @@ export class Query implements Compat<QueryImpl> {
     const deferred = new Deferred<DataSnapshot>();
     const valueCallback: UserCallback = (expSnapshot, previousChildName?) => {
       const result = new DataSnapshot(this.database, expSnapshot);
-      if (userCallback) {
-        userCallback.call(ret.context, result, previousChildName);
+      if (callback) {
+        callback.call(ret.context, result, previousChildName);
       }
       deferred.resolve(result);
     };
-    valueCallback.userCallback = userCallback;
+    valueCallback.userCallback = callback;
     valueCallback.context = ret.context;
     const cancelCallback = (error: Error) => {
       if (ret.cancel) {
@@ -364,7 +361,7 @@ export class Query implements Compat<QueryImpl> {
         break;
       default:
         throw new Error(
-          errorPrefix('Query.once', 1, false) +
+          errorPrefix('Query.once', 'eventType') +
             'must be a valid event type = "value", "child_added", "child_removed", ' +
             '"child_changed", or "child_moved".'
         );
@@ -519,10 +516,10 @@ export class Query implements Compat<QueryImpl> {
     } = { cancel: undefined, context: undefined };
     if (cancelOrContext && context) {
       ret.cancel = cancelOrContext as (a: Error) => void;
-      validateCallback(fnName, 3, ret.cancel, true);
+      validateCallback(fnName, 'cancel', ret.cancel, true);
 
       ret.context = context;
-      validateContextObject(fnName, 4, ret.context, true);
+      validateContextObject(fnName, 'context', ret.context, true);
     } else if (cancelOrContext) {
       // we have either a cancel callback or a context.
       if (typeof cancelOrContext === 'object' && cancelOrContext !== null) {
@@ -532,7 +529,7 @@ export class Query implements Compat<QueryImpl> {
         ret.cancel = cancelOrContext as (a: Error) => void;
       } else {
         throw new Error(
-          errorPrefix(fnName, 3, true) +
+          errorPrefix(fnName, 'cancelOrContext') +
             ' must either be a cancel callback or a context object.'
         );
       }
@@ -598,7 +595,7 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
     onComplete?: (error: Error | null) => void
   ): Promise<unknown> {
     validateArgCount('Reference.set', 1, 2, arguments.length);
-    validateCallback('Reference.set', 2, onComplete, true);
+    validateCallback('Reference.set', 'onComplete', onComplete, true);
     const result = set(this._delegate, newVal);
     if (onComplete) {
       result.then(
@@ -610,17 +607,17 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
   }
 
   update(
-    objectToMerge: object,
+    values: object,
     onComplete?: (a: Error | null) => void
   ): Promise<unknown> {
     validateArgCount('Reference.update', 1, 2, arguments.length);
 
-    if (Array.isArray(objectToMerge)) {
+    if (Array.isArray(values)) {
       const newObjectToMerge: { [k: string]: unknown } = {};
-      for (let i = 0; i < objectToMerge.length; ++i) {
-        newObjectToMerge['' + i] = objectToMerge[i];
+      for (let i = 0; i < values.length; ++i) {
+        newObjectToMerge['' + i] = values[i];
       }
-      objectToMerge = newObjectToMerge;
+      values = newObjectToMerge;
       warn(
         'Passing an Array to Firebase.update() is deprecated. ' +
           'Use set() if you want to overwrite the existing data, or ' +
@@ -629,9 +626,9 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
       );
     }
     validateWritablePath('Reference.update', this._delegate._path);
-    validateCallback('Reference.update', 2, onComplete, true);
+    validateCallback('Reference.update', 'onComplete', onComplete, true);
 
-    const result = update(this._delegate, objectToMerge);
+    const result = update(this._delegate, values);
     if (onComplete) {
       result.then(
         () => onComplete(null),
@@ -647,7 +644,12 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
     onComplete?: (a: Error | null) => void
   ): Promise<unknown> {
     validateArgCount('Reference.setWithPriority', 2, 3, arguments.length);
-    validateCallback('Reference.setWithPriority', 3, onComplete, true);
+    validateCallback(
+      'Reference.setWithPriority',
+      'onComplete',
+      onComplete,
+      true
+    );
 
     const result = setWithPriority(this._delegate, newVal, newPriority);
     if (onComplete) {
@@ -661,7 +663,7 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
 
   remove(onComplete?: (a: Error | null) => void): Promise<unknown> {
     validateArgCount('Reference.remove', 0, 1, arguments.length);
-    validateCallback('Reference.remove', 1, onComplete, true);
+    validateCallback('Reference.remove', 'onComplete', onComplete, true);
 
     const result = remove(this._delegate);
     if (onComplete) {
@@ -683,9 +685,19 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
     applyLocally?: boolean
   ): Promise<TransactionResult> {
     validateArgCount('Reference.transaction', 1, 3, arguments.length);
-    validateCallback('Reference.transaction', 1, transactionUpdate, false);
-    validateCallback('Reference.transaction', 2, onComplete, true);
-    validateBoolean('Reference.transaction', 3, applyLocally, true);
+    validateCallback(
+      'Reference.transaction',
+      'transactionUpdate',
+      transactionUpdate,
+      false
+    );
+    validateCallback('Reference.transaction', 'onComplete', onComplete, true);
+    validateBoolean(
+      'Reference.transaction',
+      'applyLocally',
+      applyLocally,
+      true
+    );
 
     const result = runTransaction(this._delegate, transactionUpdate, {
       applyLocally
@@ -715,7 +727,7 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
     onComplete?: (a: Error | null) => void
   ): Promise<unknown> {
     validateArgCount('Reference.setPriority', 1, 2, arguments.length);
-    validateCallback('Reference.setPriority', 2, onComplete, true);
+    validateCallback('Reference.setPriority', 'onComplete', onComplete, true);
 
     const result = setPriority(this._delegate, priority);
     if (onComplete) {
@@ -729,7 +741,7 @@ export class Reference extends Query implements Compat<ReferenceImpl> {
 
   push(value?: unknown, onComplete?: (a: Error | null) => void): Reference {
     validateArgCount('Reference.push', 0, 2, arguments.length);
-    validateCallback('Reference.push', 2, onComplete, true);
+    validateCallback('Reference.push', 'onComplete', onComplete, true);
 
     const expPromise = push(this._delegate, value);
     const promise = expPromise.then(
diff --git a/packages/database/src/api/onDisconnect.ts b/packages/database/src/api/onDisconnect.ts
index fbeb27674cc..82ea5858e43 100644
--- a/packages/database/src/api/onDisconnect.ts
+++ b/packages/database/src/api/onDisconnect.ts
@@ -26,7 +26,7 @@ export class OnDisconnect implements Compat<ExpOnDisconnect> {
 
   cancel(onComplete?: (a: Error | null) => void): Promise<void> {
     validateArgCount('OnDisconnect.cancel', 0, 1, arguments.length);
-    validateCallback('OnDisconnect.cancel', 1, onComplete, true);
+    validateCallback('OnDisconnect.cancel', 'onComplete', onComplete, true);
     const result = this._delegate.cancel();
     if (onComplete) {
       result.then(
@@ -39,7 +39,7 @@ export class OnDisconnect implements Compat<ExpOnDisconnect> {
 
   remove(onComplete?: (a: Error | null) => void): Promise<void> {
     validateArgCount('OnDisconnect.remove', 0, 1, arguments.length);
-    validateCallback('OnDisconnect.remove', 1, onComplete, true);
+    validateCallback('OnDisconnect.remove', 'onComplete', onComplete, true);
     const result = this._delegate.remove();
     if (onComplete) {
       result.then(
@@ -52,7 +52,7 @@ export class OnDisconnect implements Compat<ExpOnDisconnect> {
 
   set(value: unknown, onComplete?: (a: Error | null) => void): Promise<void> {
     validateArgCount('OnDisconnect.set', 1, 2, arguments.length);
-    validateCallback('OnDisconnect.set', 2, onComplete, true);
+    validateCallback('OnDisconnect.set', 'onComplete', onComplete, true);
     const result = this._delegate.set(value);
     if (onComplete) {
       result.then(
@@ -69,7 +69,12 @@ export class OnDisconnect implements Compat<ExpOnDisconnect> {
     onComplete?: (a: Error | null) => void
   ): Promise<void> {
     validateArgCount('OnDisconnect.setWithPriority', 2, 3, arguments.length);
-    validateCallback('OnDisconnect.setWithPriority', 3, onComplete, true);
+    validateCallback(
+      'OnDisconnect.setWithPriority',
+      'onComplete',
+      onComplete,
+      true
+    );
     const result = this._delegate.setWithPriority(value, priority);
     if (onComplete) {
       result.then(
@@ -96,7 +101,7 @@ export class OnDisconnect implements Compat<ExpOnDisconnect> {
           'existing data, or an Object with integer keys if you really do want to only update some of the children.'
       );
     }
-    validateCallback('OnDisconnect.update', 2, onComplete, true);
+    validateCallback('OnDisconnect.update', 'onComplete', onComplete, true);
     const result = this._delegate.update(objectToMerge);
     if (onComplete) {
       result.then(
diff --git a/packages/database/src/core/util/validation.ts b/packages/database/src/core/util/validation.ts
index 2a50b13d0f7..356f03f3ac2 100644
--- a/packages/database/src/core/util/validation.ts
+++ b/packages/database/src/core/util/validation.ts
@@ -95,20 +95,15 @@ export const isValidPriority = function (priority: unknown): boolean {
  */
 export const validateFirebaseDataArg = function (
   fnName: string,
-  argumentNumber: number,
-  data: unknown,
+  value: unknown,
   path: Path,
   optional: boolean
 ) {
-  if (optional && data === undefined) {
+  if (optional && value === undefined) {
     return;
   }
 
-  validateFirebaseData(
-    errorPrefixFxn(fnName, argumentNumber, optional),
-    data,
-    path
-  );
+  validateFirebaseData(errorPrefixFxn(fnName, 'value'), value, path);
 };
 
 /**
@@ -257,7 +252,6 @@ export const validateFirebaseMergePaths = function (
  */
 export const validateFirebaseMergeDataArg = function (
   fnName: string,
-  argumentNumber: number,
   data: unknown,
   path: Path,
   optional: boolean
@@ -266,7 +260,7 @@ export const validateFirebaseMergeDataArg = function (
     return;
   }
 
-  const errorPrefix = errorPrefixFxn(fnName, argumentNumber, optional);
+  const errorPrefix = errorPrefixFxn(fnName, 'values');
 
   if (!(data && typeof data === 'object') || Array.isArray(data)) {
     throw new Error(
@@ -296,7 +290,6 @@ export const validateFirebaseMergeDataArg = function (
 
 export const validatePriority = function (
   fnName: string,
-  argumentNumber: number,
   priority: unknown,
   optional: boolean
 ) {
@@ -305,7 +298,7 @@ export const validatePriority = function (
   }
   if (isInvalidJSONNumber(priority)) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
+      errorPrefixFxn(fnName, 'priority') +
         'is ' +
         priority.toString() +
         ', but must be a valid Firebase priority (a string, finite number, ' +
@@ -315,7 +308,7 @@ export const validatePriority = function (
   // Special case to allow importing data with a .sv.
   if (!isValidPriority(priority)) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
+      errorPrefixFxn(fnName, 'priority') +
         'must be a valid Firebase priority ' +
         '(a string, finite number, server value, or null).'
     );
@@ -324,7 +317,6 @@ export const validatePriority = function (
 
 export const validateEventType = function (
   fnName: string,
-  argumentNumber: number,
   eventType: string,
   optional: boolean
 ) {
@@ -341,7 +333,7 @@ export const validateEventType = function (
       break;
     default:
       throw new Error(
-        errorPrefixFxn(fnName, argumentNumber, optional) +
+        errorPrefixFxn(fnName, 'eventType') +
           'must be a valid event type = "value", "child_added", "child_removed", ' +
           '"child_changed", or "child_moved".'
       );
@@ -350,7 +342,7 @@ export const validateEventType = function (
 
 export const validateKey = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   key: string,
   optional: boolean
 ) {
@@ -359,7 +351,7 @@ export const validateKey = function (
   }
   if (!isValidKey(key)) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
+      errorPrefixFxn(fnName, argumentName) +
         'was an invalid key = "' +
         key +
         '".  Firebase keys must be non-empty strings and ' +
@@ -370,7 +362,7 @@ export const validateKey = function (
 
 export const validatePathString = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   pathString: string,
   optional: boolean
 ) {
@@ -380,7 +372,7 @@ export const validatePathString = function (
 
   if (!isValidPathString(pathString)) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
+      errorPrefixFxn(fnName, argumentName) +
         'was an invalid path = "' +
         pathString +
         '". Paths must be non-empty strings and ' +
@@ -391,7 +383,7 @@ export const validatePathString = function (
 
 export const validateRootPathString = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   pathString: string,
   optional: boolean
 ) {
@@ -400,7 +392,7 @@ export const validateRootPathString = function (
     pathString = pathString.replace(/^\/*\.info(\/|$)/, '/');
   }
 
-  validatePathString(fnName, argumentNumber, pathString, optional);
+  validatePathString(fnName, argumentName, pathString, optional);
 };
 
 export const validateWritablePath = function (fnName: string, path: Path) {
@@ -411,7 +403,6 @@ export const validateWritablePath = function (fnName: string, path: Path) {
 
 export const validateUrl = function (
   fnName: string,
-  argumentNumber: number,
   parsedUrl: { repoInfo: RepoInfo; path: Path }
 ) {
   // TODO = Validate server better.
@@ -424,33 +415,16 @@ export const validateUrl = function (
     (pathString.length !== 0 && !isValidRootPathString(pathString))
   ) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, false) +
+      errorPrefixFxn(fnName, 'url') +
         'must be a valid firebase URL and ' +
         'the path can\'t contain ".", "#", "$", "[", or "]".'
     );
   }
 };
 
-export const validateCredential = function (
-  fnName: string,
-  argumentNumber: number,
-  cred: unknown,
-  optional: boolean
-) {
-  if (optional && cred === undefined) {
-    return;
-  }
-  if (!(typeof cred === 'string')) {
-    throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
-        'must be a valid credential (a string).'
-    );
-  }
-};
-
 export const validateBoolean = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   bool: unknown,
   optional: boolean
 ) {
@@ -459,14 +433,14 @@ export const validateBoolean = function (
   }
   if (typeof bool !== 'boolean') {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) + 'must be a boolean.'
+      errorPrefixFxn(fnName, argumentName) + 'must be a boolean.'
     );
   }
 };
 
 export const validateString = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   string: unknown,
   optional: boolean
 ) {
@@ -475,15 +449,14 @@ export const validateString = function (
   }
   if (!(typeof string === 'string')) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
-        'must be a valid string.'
+      errorPrefixFxn(fnName, argumentName) + 'must be a valid string.'
     );
   }
 };
 
 export const validateObject = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   obj: unknown,
   optional: boolean
 ) {
@@ -492,15 +465,14 @@ export const validateObject = function (
   }
   if (!(obj && typeof obj === 'object') || obj === null) {
     throw new Error(
-      errorPrefixFxn(fnName, argumentNumber, optional) +
-        'must be a valid object.'
+      errorPrefixFxn(fnName, argumentName) + 'must be a valid object.'
     );
   }
 };
 
 export const validateObjectContainsKey = function (
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   obj: unknown,
   key: string,
   optional: boolean,
@@ -515,7 +487,7 @@ export const validateObjectContainsKey = function (
       return;
     } else {
       throw new Error(
-        errorPrefixFxn(fnName, argumentNumber, optional) +
+        errorPrefixFxn(fnName, argumentName) +
           'must contain the key "' +
           key +
           '"'
@@ -535,7 +507,7 @@ export const validateObjectContainsKey = function (
     ) {
       if (optional) {
         throw new Error(
-          errorPrefixFxn(fnName, argumentNumber, optional) +
+          errorPrefixFxn(fnName, argumentName) +
             'contains invalid value for key "' +
             key +
             '" (must be of type "' +
@@ -544,7 +516,7 @@ export const validateObjectContainsKey = function (
         );
       } else {
         throw new Error(
-          errorPrefixFxn(fnName, argumentNumber, optional) +
+          errorPrefixFxn(fnName, argumentName) +
             'must contain the key "' +
             key +
             '" with type "' +
diff --git a/packages/database/src/exp/Database.ts b/packages/database/src/exp/Database.ts
index a8b86bdc183..db01fe5bbb3 100644
--- a/packages/database/src/exp/Database.ts
+++ b/packages/database/src/exp/Database.ts
@@ -132,7 +132,7 @@ export function repoManagerDatabaseFromApp(
       ? new EmulatorAdminTokenProvider()
       : new FirebaseAuthTokenProvider(app.name, app.options, authProvider);
 
-  validateUrl('Invalid Firebase Database URL', 1, parsedUrl);
+  validateUrl('Invalid Firebase Database URL', parsedUrl);
   if (!pathIsEmpty(parsedUrl.path)) {
     fatal(
       'Database URL must point to the root of a Firebase Database ' +
diff --git a/packages/database/src/exp/OnDisconnect.ts b/packages/database/src/exp/OnDisconnect.ts
index 8441cae5aab..efb57f9eda9 100644
--- a/packages/database/src/exp/OnDisconnect.ts
+++ b/packages/database/src/exp/OnDisconnect.ts
@@ -60,7 +60,7 @@ export class OnDisconnect {
 
   set(value: unknown): Promise<void> {
     validateWritablePath('OnDisconnect.set', this._path);
-    validateFirebaseDataArg('OnDisconnect.set', 1, value, this._path, false);
+    validateFirebaseDataArg('OnDisconnect.set', value, this._path, false);
     const deferred = new Deferred<void>();
     repoOnDisconnectSet(
       this._repo,
@@ -78,12 +78,11 @@ export class OnDisconnect {
     validateWritablePath('OnDisconnect.setWithPriority', this._path);
     validateFirebaseDataArg(
       'OnDisconnect.setWithPriority',
-      1,
       value,
       this._path,
       false
     );
-    validatePriority('OnDisconnect.setWithPriority', 2, priority, false);
+    validatePriority('OnDisconnect.setWithPriority', priority, false);
 
     const deferred = new Deferred<void>();
     repoOnDisconnectSetWithPriority(
@@ -96,12 +95,11 @@ export class OnDisconnect {
     return deferred.promise;
   }
 
-  update(objectToMerge: Indexable): Promise<void> {
+  update(values: Indexable): Promise<void> {
     validateWritablePath('OnDisconnect.update', this._path);
     validateFirebaseMergeDataArg(
       'OnDisconnect.update',
-      1,
-      objectToMerge,
+      values,
       this._path,
       false
     );
@@ -109,7 +107,7 @@ export class OnDisconnect {
     repoOnDisconnectUpdate(
       this._repo,
       this._path,
-      objectToMerge,
+      values,
       deferred.wrapCallback(() => {})
     );
     return deferred.promise;
diff --git a/packages/database/src/exp/Reference_impl.ts b/packages/database/src/exp/Reference_impl.ts
index 35bec7fe164..948ad2e3cc7 100644
--- a/packages/database/src/exp/Reference_impl.ts
+++ b/packages/database/src/exp/Reference_impl.ts
@@ -357,7 +357,7 @@ export function refFromURL(db: FirebaseDatabase, url: string): ReferenceImpl {
   db = getModularInstance(db);
   db._checkNotDeleted('refFromURL');
   const parsedURL = parseRepoInfo(url, db._repo.repoInfo_.nodeAdmin);
-  validateUrl('refFromURL', 1, parsedURL);
+  validateUrl('refFromURL', parsedURL);
 
   const repoInfo = parsedURL.repoInfo;
   if (
@@ -381,10 +381,9 @@ export function refFromURL(db: FirebaseDatabase, url: string): ReferenceImpl {
 export function child(ref: Reference, path: string): ReferenceImpl {
   ref = getModularInstance(ref);
   if (pathGetFront(ref._path) === null) {
-    // TODO(database-exp): Remove argument numbers from all error messages
-    validateRootPathString('child', 1, path, false);
+    validateRootPathString('child', 'path', path, false);
   } else {
-    validatePathString('child', 1, path, false);
+    validatePathString('child', 'path', path, false);
   }
   return new ReferenceImpl(ref._repo, pathChild(ref._path, path));
 }
@@ -401,7 +400,7 @@ export interface ThenableReferenceImpl
 export function push(ref: Reference, value?: unknown): ThenableReferenceImpl {
   ref = getModularInstance(ref);
   validateWritablePath('push', ref._path);
-  validateFirebaseDataArg('push', 1, value, ref._path, true);
+  validateFirebaseDataArg('push', value, ref._path, true);
   const now = repoServerTime(ref._repo);
   const name = nextPushId(now);
 
@@ -434,7 +433,7 @@ export function remove(ref: Reference): Promise<void> {
 export function set(ref: Reference, value: unknown): Promise<void> {
   ref = getModularInstance(ref);
   validateWritablePath('set', ref._path);
-  validateFirebaseDataArg('set', 1, value, ref._path, false);
+  validateFirebaseDataArg('set', value, ref._path, false);
   const deferred = new Deferred<void>();
   repoSetWithPriority(
     ref._repo,
@@ -452,7 +451,7 @@ export function setPriority(
 ): Promise<void> {
   ref = getModularInstance(ref);
   validateWritablePath('setPriority', ref._path);
-  validatePriority('setPriority', 1, priority, false);
+  validatePriority('setPriority', priority, false);
   const deferred = new Deferred<void>();
   repoSetWithPriority(
     ref._repo,
@@ -470,9 +469,8 @@ export function setWithPriority(
   priority: string | number | null
 ): Promise<void> {
   validateWritablePath('setWithPriority', ref._path);
-  validateFirebaseDataArg('setWithPriority', 1, value, ref._path, false);
-  validatePriority('setWithPriority', 2, priority, false);
-
+  validateFirebaseDataArg('setWithPriority', value, ref._path, false);
+  validatePriority('setWithPriority', priority, false);
   if (ref.key === '.length' || ref.key === '.keys') {
     throw 'setWithPriority failed: ' + ref.key + ' is a read-only object.';
   }
@@ -489,7 +487,7 @@ export function setWithPriority(
 }
 
 export function update(ref: Reference, values: object): Promise<void> {
-  validateFirebaseMergeDataArg('update', 1, values, ref._path, false);
+  validateFirebaseMergeDataArg('update', values, ref._path, false);
   const deferred = new Deferred<void>();
   repoUpdate(
     ref._repo,
@@ -1006,7 +1004,7 @@ class QueryEndAtConstraint extends QueryConstraint {
   }
 
   _apply<T>(query: QueryImpl): QueryImpl {
-    validateFirebaseDataArg('endAt', 1, this._value, query._path, true);
+    validateFirebaseDataArg('endAt', this._value, query._path, true);
     const newParams = queryParamsEndAt(
       query._queryParams,
       this._value,
@@ -1033,7 +1031,7 @@ export function endAt(
   value: number | string | boolean | null,
   key?: string
 ): QueryConstraint {
-  validateKey('endAt', 2, key, true);
+  validateKey('endAt', 'key', key, true);
   return new QueryEndAtConstraint(value, key);
 }
 
@@ -1048,7 +1046,7 @@ class QueryEndBeforeConstraint extends QueryConstraint {
   }
 
   _apply<T>(query: QueryImpl): QueryImpl {
-    validateFirebaseDataArg('endBefore', 1, this._value, query._path, false);
+    validateFirebaseDataArg('endBefore', this._value, query._path, false);
     const newParams = queryParamsEndBefore(
       query._queryParams,
       this._value,
@@ -1075,7 +1073,7 @@ export function endBefore(
   value: number | string | boolean | null,
   key?: string
 ): QueryConstraint {
-  validateKey('endBefore', 2, key, true);
+  validateKey('endBefore', 'key', key, true);
   return new QueryEndBeforeConstraint(value, key);
 }
 
@@ -1090,7 +1088,7 @@ class QueryStartAtConstraint extends QueryConstraint {
   }
 
   _apply<T>(query: QueryImpl): QueryImpl {
-    validateFirebaseDataArg('startAt', 1, this._value, query._path, true);
+    validateFirebaseDataArg('startAt', this._value, query._path, true);
     const newParams = queryParamsStartAt(
       query._queryParams,
       this._value,
@@ -1117,7 +1115,7 @@ export function startAt(
   value: number | string | boolean | null = null,
   key?: string
 ): QueryConstraint {
-  validateKey('startAt', 2, key, true);
+  validateKey('startAt', 'key', key, true);
   return new QueryStartAtConstraint(value, key);
 }
 
@@ -1132,7 +1130,7 @@ class QueryStartAfterConstraint extends QueryConstraint {
   }
 
   _apply<T>(query: QueryImpl): QueryImpl {
-    validateFirebaseDataArg('startAfter', 1, this._value, query._path, false);
+    validateFirebaseDataArg('startAfter', this._value, query._path, false);
     const newParams = queryParamsStartAfter(
       query._queryParams,
       this._value,
@@ -1159,7 +1157,7 @@ export function startAfter(
   value: number | string | boolean | null,
   key?: string
 ): QueryConstraint {
-  validateKey('startAfter', 2, key, true);
+  validateKey('startAfter', 'key', key, true);
   return new QueryStartAfterConstraint(value, key);
 }
 
@@ -1266,7 +1264,7 @@ export function orderByChild(path: string): QueryConstraint {
       'orderByChild: "$value" is invalid.  Use orderByValue() instead.'
     );
   }
-  validatePathString('orderByChild', 1, path, false);
+  validatePathString('orderByChild', 'path', path, false);
   return new QueryOrderByChildConstraint(path);
 }
 
@@ -1341,7 +1339,7 @@ class QueryEqualToValueConstraint extends QueryConstraint {
   }
 
   _apply<T>(query: QueryImpl): QueryImpl {
-    validateFirebaseDataArg('equalTo', 1, this._value, query._path, false);
+    validateFirebaseDataArg('equalTo', this._value, query._path, false);
     if (query._queryParams.hasStart()) {
       throw new Error(
         'equalTo: Starting point was already set (by another call to startAt/startAfter or ' +
@@ -1364,7 +1362,7 @@ export function equalTo(
   value: number | string | boolean | null,
   key?: string
 ): QueryConstraint {
-  validateKey('equalTo', 2, key, true);
+  validateKey('equalTo', 'key', key, true);
   return new QueryEqualToValueConstraint(value, key);
 }
 
diff --git a/packages/database/test/exp/integration.test.ts b/packages/database/test/exp/integration.test.ts
index 36f90e971d3..9790c88d24c 100644
--- a/packages/database/test/exp/integration.test.ts
+++ b/packages/database/test/exp/integration.test.ts
@@ -27,15 +27,15 @@ import {
   ref,
   refFromURL
 } from '../../exp/index';
-import { set } from '../../src/exp/Reference_impl';
+import { onValue, set } from '../../src/exp/Reference_impl';
+import { EventAccumulatorFactory } from '../helpers/EventAccumulator';
 import { DATABASE_ADDRESS, DATABASE_URL } from '../helpers/util';
 
 export function createTestApp() {
   return initializeApp({ databaseURL: DATABASE_URL });
 }
 
-// TODO(database-exp): Re-enable these tests
-describe.skip('Database Tests', () => {
+describe('Database@exp Tests', () => {
   let defaultApp;
 
   beforeEach(() => {
@@ -65,7 +65,7 @@ describe.skip('Database Tests', () => {
     expect(db.app).to.equal(defaultApp);
   });
 
-  it('Can set and ge tref', async () => {
+  it('Can set and get ref', async () => {
     const db = getDatabase(defaultApp);
     await set(ref(db, 'foo/bar'), 'foobar');
     const snap = await get(ref(db, 'foo/bar'));
@@ -77,6 +77,60 @@ describe.skip('Database Tests', () => {
     await get(refFromURL(db, `${DATABASE_ADDRESS}/foo/bar`));
   });
 
+  it('Can get updates', async () => {
+    const db = getDatabase(defaultApp);
+    const fooRef = ref(db, 'foo');
+
+    const ea = EventAccumulatorFactory.waitsForCount(2);
+    onValue(fooRef, snap => {
+      ea.addEvent(snap.val());
+    });
+
+    await set(fooRef, 'a');
+    await set(fooRef, 'b');
+
+    const [snap1, snap2] = await ea.promise;
+    expect(snap1).to.equal('a');
+    expect(snap2).to.equal('b');
+  });
+
+  it('Can use onlyOnce', async () => {
+    const db = getDatabase(defaultApp);
+    const fooRef = ref(db, 'foo');
+
+    const ea = EventAccumulatorFactory.waitsForCount(1);
+    onValue(
+      fooRef,
+      snap => {
+        ea.addEvent(snap.val());
+      },
+      { onlyOnce: true }
+    );
+
+    await set(fooRef, 'a');
+    await set(fooRef, 'b');
+
+    const [snap1] = await ea.promise;
+    expect(snap1).to.equal('a');
+  });
+
+  it('Can unsubscribe', async () => {
+    const db = getDatabase(defaultApp);
+    const fooRef = ref(db, 'foo');
+
+    const ea = EventAccumulatorFactory.waitsForCount(1);
+    const unsubscribe = onValue(fooRef, snap => {
+      ea.addEvent(snap.val());
+    });
+
+    await set(fooRef, 'a');
+    unsubscribe();
+    await set(fooRef, 'b');
+
+    const [snap1] = await ea.promise;
+    expect(snap1).to.equal('a');
+  });
+
   it('Can goOffline/goOnline', async () => {
     const db = getDatabase(defaultApp);
     goOffline(db);
diff --git a/packages/util/src/validation.ts b/packages/util/src/validation.ts
index a4751801ff2..372144b6645 100644
--- a/packages/util/src/validation.ts
+++ b/packages/util/src/validation.ts
@@ -53,39 +53,11 @@ export const validateArgCount = function (
  * Generates a string to prefix an error message about failed argument validation
  *
  * @param fnName The function name
- * @param argumentNumber The index of the argument
- * @param optional Whether or not the argument is optional
+ * @param argName The name of the argument
  * @return The prefix to add to the error thrown for validation.
  */
-export function errorPrefix(
-  fnName: string,
-  argumentNumber: number,
-  optional: boolean
-): string {
-  let argName = '';
-  switch (argumentNumber) {
-    case 1:
-      argName = optional ? 'first' : 'First';
-      break;
-    case 2:
-      argName = optional ? 'second' : 'Second';
-      break;
-    case 3:
-      argName = optional ? 'third' : 'Third';
-      break;
-    case 4:
-      argName = optional ? 'fourth' : 'Fourth';
-      break;
-    default:
-      throw new Error(
-        'errorPrefix called with argumentNumber > 4.  Need to update it?'
-      );
-  }
-
-  let error = fnName + ' failed: ';
-
-  error += argName + ' argument ';
-  return error;
+export function errorPrefix(fnName: string, argName: string): string {
+  return `${fnName} failed: ${argName} argument `;
 }
 
 /**
@@ -96,7 +68,6 @@ export function errorPrefix(
  */
 export function validateNamespace(
   fnName: string,
-  argumentNumber: number,
   namespace: string,
   optional: boolean
 ): void {
@@ -106,15 +77,14 @@ export function validateNamespace(
   if (typeof namespace !== 'string') {
     //TODO: I should do more validation here. We only allow certain chars in namespaces.
     throw new Error(
-      errorPrefix(fnName, argumentNumber, optional) +
-        'must be a valid firebase namespace.'
+      errorPrefix(fnName, 'namespace') + 'must be a valid firebase namespace.'
     );
   }
 }
 
 export function validateCallback(
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   // eslint-disable-next-line @typescript-eslint/ban-types
   callback: Function,
   optional: boolean
@@ -124,15 +94,14 @@ export function validateCallback(
   }
   if (typeof callback !== 'function') {
     throw new Error(
-      errorPrefix(fnName, argumentNumber, optional) +
-        'must be a valid function.'
+      errorPrefix(fnName, argumentName) + 'must be a valid function.'
     );
   }
 }
 
 export function validateContextObject(
   fnName: string,
-  argumentNumber: number,
+  argumentName: string,
   context: unknown,
   optional: boolean
 ): void {
@@ -141,8 +110,7 @@ export function validateContextObject(
   }
   if (typeof context !== 'object' || context === null) {
     throw new Error(
-      errorPrefix(fnName, argumentNumber, optional) +
-        'must be a valid context object.'
+      errorPrefix(fnName, argumentName) + 'must be a valid context object.'
     );
   }
 }