diff --git a/README.md b/README.md
index ae7796a..93c7903 100644
--- a/README.md
+++ b/README.md
@@ -98,6 +98,7 @@ new Store(dbName, options)
 | **`options.remote`** | Object | PouchDB instance | Yes (ignores `remoteBaseUrl` from [Store.defaults](#storedefaults))
 | **`options.remote`** | Promise | Resolves to either string or PouchDB instance | see above
 | **`options.PouchDB`** | Constructor | [PouchDB custom builds](https://pouchdb.com/custom.html) | Yes (unless preset using [Store.defaults](#storedefaults)))
+| **`options.validate`** | Function | Validation function to execute before DB operations (Can return promise for async validation) | No
 
 Returns `store` API.
 
diff --git a/index.js b/index.js
index 3ef3c55..8b2356e 100644
--- a/index.js
+++ b/index.js
@@ -33,6 +33,7 @@ function Store (dbName, options) {
     dbName: dbName,
     PouchDB: options.PouchDB,
     emitter: emitter,
+    validate: options.validate,
     get remote () {
       return options.remote
     }
diff --git a/lib/helpers/add-many.js b/lib/helpers/add-many.js
index 10f7f2e..45a91e2 100644
--- a/lib/helpers/add-many.js
+++ b/lib/helpers/add-many.js
@@ -1,5 +1,6 @@
 var clone = require('lodash/clone')
 var uuid = require('pouchdb-utils').uuid
+var validate = require('../validate')
 
 var addTimestamps = require('../utils/add-timestamps')
 var bulkDocs = require('./db-bulk-docs')
@@ -17,5 +18,16 @@ module.exports = function addMany (state, docs, prefix) {
     })
   }
 
-  return bulkDocs(state, docs)
+  var validationPromises = docs.map(function (doc) {
+    return validate(state, doc)
+  })
+
+  return Promise.all(validationPromises)
+
+  .then(function () {
+    return bulkDocs(state, docs)
+  })
+  .catch(function (error) {
+    throw error
+  })
 }
diff --git a/lib/helpers/add-one.js b/lib/helpers/add-one.js
index 1247eed..180b871 100644
--- a/lib/helpers/add-one.js
+++ b/lib/helpers/add-one.js
@@ -4,6 +4,7 @@ var clone = require('lodash/clone')
 var PouchDBErrors = require('pouchdb-errors')
 var Promise = require('lie')
 var uuid = require('pouchdb-utils').uuid
+var validate = require('../validate')
 
 var internals = addOne.internals = {}
 internals.addTimestamps = require('../utils/add-timestamps')
@@ -26,8 +27,11 @@ function addOne (state, doc, prefix) {
 
   delete doc.hoodie
 
-  return internals.put(state, internals.addTimestamps(doc))
+  return validate(state, doc)
 
+  .then(function () {
+    return internals.put(state, internals.addTimestamps(doc))
+  })
   .catch(function (error) {
     if (error.status === 409) {
       var conflict = new Error('Object with id "' + doc._id + '" already exists')
diff --git a/lib/validate.js b/lib/validate.js
new file mode 100644
index 0000000..718fe50
--- /dev/null
+++ b/lib/validate.js
@@ -0,0 +1,40 @@
+module.exports = validate
+
+var Promise = require('lie')
+
+function validate (state, doc) {
+  if (state.validate === undefined) {
+    return Promise.resolve()
+  }
+
+  return Promise.resolve()
+
+  .then(function () {
+    return state.validate(doc)
+  })
+  .catch(function (rejectValue) {
+    var error = new Error()
+
+    if (rejectValue instanceof Error) {
+      Object.keys(rejectValue).map(function (key) {
+        error[key] = rejectValue[key]
+      })
+
+      if (rejectValue.message) {
+        error.message = rejectValue.message
+      } else {
+        error.message = 'document validation failed'
+      }
+    } else {
+      if (typeof rejectValue === 'string') {
+        error.message = rejectValue
+      } else {
+        error.message = 'check error value for more details'
+        error.value = rejectValue
+      }
+    }
+
+    error.name = 'ValidationError'
+    throw error
+  })
+}
diff --git a/tests/integration/add.js b/tests/integration/add.js
index 4bf8d65..9a8e2be 100644
--- a/tests/integration/add.js
+++ b/tests/integration/add.js
@@ -124,7 +124,8 @@ test('adds multiple objects to db', function (t) {
   var name = uniqueName()
   var store = new Store(name, {
     PouchDB: PouchDB,
-    remote: 'remote-' + name
+    remote: 'remote-' + name,
+    validate: function () {}
   })
 
   store.add({
@@ -164,6 +165,34 @@ test('adds multiple objects to db', function (t) {
   .catch(t.error)
 })
 
+test('fail validation adding multiple objects to db', function (t) {
+  t.plan(2)
+
+  var name = uniqueName()
+  var store = new Store(name, {
+    PouchDB: PouchDB,
+    remote: 'remote-' + name,
+    validate: function () { throw new Error('Validation failed for the given docs') }
+  })
+
+  store.add([{
+    foo: 'bar'
+  }, {
+    foo: 'baz'
+  }, {
+    _id: 'foo',
+    foo: 'baz'
+  }])
+
+  .then(function () {
+    t.fail('Expecting ValidationError')
+  })
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError')
+    t.is(error.message, 'Validation failed for the given docs')
+  })
+})
+
 test('store.add(object) makes createdAt and updatedAt timestamps', function (t) {
   t.plan(4)
 
diff --git a/tests/unit/add-one-test.js b/tests/unit/add-one-test.js
index b8d714a..a7126d9 100644
--- a/tests/unit/add-one-test.js
+++ b/tests/unit/add-one-test.js
@@ -12,6 +12,7 @@ test('add-one non-409 error', function (t) {
   simple.mock(addOne.internals, 'addTimestamps')
 
   var state = {}
+
   var doc = {}
   addOne(state, doc)
 
@@ -25,3 +26,174 @@ test('add-one non-409 error', function (t) {
     simple.restore()
   })
 })
+
+test('add-one ValidationError', function (t) {
+  t.plan(2)
+
+  var state = {
+    validate: function () { throw new Error('Validation failed for the given docs') }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'Validation failed for the given docs', 'error message matches intent')
+  })
+})
+
+test('add-one validate rejects with Error (without message)', function (t) {
+  t.plan(2)
+
+  var state = {
+    validate: function () { return Promise.reject(new Error()) }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'document validation failed', 'error message matches intent')
+  })
+})
+
+test('add-one validate rejects with Error (with message)', function (t) {
+  t.plan(2)
+
+  var state = {
+    validate: function () { return Promise.reject(new Error('Validation failed for the given docs')) }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'Validation failed for the given docs', 'error message matches intent')
+  })
+})
+
+test('add-one validate rejects with a string', function (t) {
+  t.plan(2)
+
+  var state = {
+    validate: function () { return Promise.reject('Validation failed for the given docs') }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'Validation failed for the given docs', 'error message matches intent')
+  })
+})
+
+test('add-one validate rejects with a value I', function (t) {
+  t.plan(3)
+
+  var state = {
+    validate: function () { return Promise.reject(false) }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'check error value for more details', 'error message matches intent')
+    t.is(error.value, false, 'error.value is false')
+  })
+})
+
+test('add-one validate rejects with a value II', function (t) {
+  t.plan(3)
+
+  var state = {
+    validate: function () { return Promise.reject(1) }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'check error value for more details', 'error message matches intent')
+    t.is(error.value, 1, 'error.value is 1')
+  })
+})
+
+test('add-one validate rejects with a value III', function (t) {
+  t.plan(4)
+
+  var state = {
+    validate: function () { return Promise.reject({ failure: true, tries: 1 }) }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'check error value for more details', 'error message matches intent')
+    t.is(error.value.failure, true, 'error.value.failure is true')
+    t.is(error.value.tries, 1, 'error.value.tries is 1')
+  })
+})
+
+test('add-one validation fails with custom error', function (t) {
+  t.plan(4)
+
+  var customError = new Error('custom error message')
+
+  customError.status = 401
+  customError.errorCode = 'DB_401'
+
+  var state = {
+    validate: function () { throw customError }
+  }
+
+  var doc = {}
+  addOne(state, doc)
+
+  .then(function () {
+    t.fail('should throw an ValidationError')
+  })
+
+  .catch(function (error) {
+    t.is(error.name, 'ValidationError', 'validation error name matches')
+    t.is(error.message, 'custom error message', 'error message matches intent')
+    t.is(error.status, 401, 'error.status is 401')
+    t.is(error.errorCode, 'DB_401', 'error.errorCode is DB_401')
+  })
+})