diff --git a/app/Api/V1/Controllers/AttachmentController.php b/app/Api/V1/Controllers/AttachmentController.php
index e5a3a93d84..83c3d74321 100644
--- a/app/Api/V1/Controllers/AttachmentController.php
+++ b/app/Api/V1/Controllers/AttachmentController.php
@@ -98,15 +98,15 @@ class AttachmentController extends Controller
     public function download(Attachment $attachment): LaravelResponse
     {
         if (false === $attachment->uploaded) {
-            throw new FireflyException(trans('api.error_no_upload'));
+            throw new FireflyException('200000: File has not been uploaded (yet).');
         }
         if (0 === $attachment->size) {
-            throw new FireflyException(trans('api.error_no_upload'));
+            throw new FireflyException('200000: File has not been uploaded (yet).');
         }
         if ($this->repository->exists($attachment)) {
             $content = $this->repository->getContent($attachment);
             if ('' === $content) {
-                throw new FireflyException(trans('api.error_no_upload'));
+                throw new FireflyException('200002: File is empty (zero bytes).');
             }
             $quoted  = sprintf('"%s"', addcslashes(basename($attachment->filename), '"\\'));
 
@@ -125,7 +125,7 @@ class AttachmentController extends Controller
 
             return $response;
         }
-        throw new FireflyException(trans('api.error_file_lost'));
+        throw new FireflyException('200003: File does not exist.');
     }
 
     /**
diff --git a/app/Api/V1/Controllers/BillController.php b/app/Api/V1/Controllers/BillController.php
index 9e9424a1bb..290864d023 100644
--- a/app/Api/V1/Controllers/BillController.php
+++ b/app/Api/V1/Controllers/BillController.php
@@ -211,20 +211,16 @@ class BillController extends Controller
      */
     public function store(BillRequest $request): JsonResponse
     {
-        $bill = $this->repository->store($request->getAll());
-        if (null !== $bill) {
-            $manager = $this->getManager();
+        $bill    = $this->repository->store($request->getAll());
+        $manager = $this->getManager();
 
-            /** @var BillTransformer $transformer */
-            $transformer = app(BillTransformer::class);
-            $transformer->setParameters($this->parameters);
+        /** @var BillTransformer $transformer */
+        $transformer = app(BillTransformer::class);
+        $transformer->setParameters($this->parameters);
 
-            $resource = new Item($bill, $transformer, 'bills');
-
-            return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
-        }
-        throw new FireflyException(trans('api.error_store_bill')); // @codeCoverageIgnore
+        $resource = new Item($bill, $transformer, 'bills');
 
+        return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
     }
 
     /**
diff --git a/app/Api/V1/Controllers/BudgetController.php b/app/Api/V1/Controllers/BudgetController.php
index 5ea5793cf7..5e07482b5c 100644
--- a/app/Api/V1/Controllers/BudgetController.php
+++ b/app/Api/V1/Controllers/BudgetController.php
@@ -187,19 +187,16 @@ class BudgetController extends Controller
      */
     public function store(BudgetRequest $request): JsonResponse
     {
-        $budget = $this->repository->store($request->getAll());
-        if (null !== $budget) {
-            $manager = $this->getManager();
+        $budget  = $this->repository->store($request->getAll());
+        $manager = $this->getManager();
 
-            /** @var BudgetTransformer $transformer */
-            $transformer = app(BudgetTransformer::class);
-            $transformer->setParameters($this->parameters);
+        /** @var BudgetTransformer $transformer */
+        $transformer = app(BudgetTransformer::class);
+        $transformer->setParameters($this->parameters);
 
-            $resource = new Item($budget, $transformer, 'budgets');
+        $resource = new Item($budget, $transformer, 'budgets');
 
-            return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
-        }
-        throw new FireflyException(trans('api.error_store_budget')); // @codeCoverageIgnore
+        return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
     }
 
     /**
diff --git a/app/Api/V1/Controllers/BudgetLimitController.php b/app/Api/V1/Controllers/BudgetLimitController.php
index d1ac952326..2ff32cfa18 100644
--- a/app/Api/V1/Controllers/BudgetLimitController.php
+++ b/app/Api/V1/Controllers/BudgetLimitController.php
@@ -165,7 +165,7 @@ class BudgetLimitController extends Controller
         $data   = $request->getAll();
         $budget = $this->repository->findNull($data['budget_id']);
         if (null === $budget) {
-            throw new FireflyException(trans('api.error_unknown_budget'));
+            throw new FireflyException('200004: Budget does not exist.');
         }
         $data['budget'] = $budget;
         $budgetLimit    = $this->blRepository->storeBudgetLimit($data);
diff --git a/app/Api/V1/Controllers/CategoryController.php b/app/Api/V1/Controllers/CategoryController.php
index c2ff07d87b..1021fbbbca 100644
--- a/app/Api/V1/Controllers/CategoryController.php
+++ b/app/Api/V1/Controllers/CategoryController.php
@@ -152,18 +152,15 @@ class CategoryController extends Controller
     public function store(CategoryRequest $request): JsonResponse
     {
         $category = $this->repository->store($request->getAll());
-        if (null !== $category) {
-            $manager = $this->getManager();
+        $manager = $this->getManager();
 
-            /** @var CategoryTransformer $transformer */
-            $transformer = app(CategoryTransformer::class);
-            $transformer->setParameters($this->parameters);
+        /** @var CategoryTransformer $transformer */
+        $transformer = app(CategoryTransformer::class);
+        $transformer->setParameters($this->parameters);
 
-            $resource = new Item($category, $transformer, 'categories');
+        $resource = new Item($category, $transformer, 'categories');
 
-            return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
-        }
-        throw new FireflyException(trans('api.error_store_new_category')); // @codeCoverageIgnore
+        return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
     }
 
     /**
diff --git a/app/Api/V1/Controllers/ConfigurationController.php b/app/Api/V1/Controllers/ConfigurationController.php
index 95a969b7c3..d6d426f269 100644
--- a/app/Api/V1/Controllers/ConfigurationController.php
+++ b/app/Api/V1/Controllers/ConfigurationController.php
@@ -57,7 +57,7 @@ class ConfigurationController extends Controller
                 $admin = auth()->user();
 
                 if (!$this->repository->hasRole($admin, 'owner')) {
-                    throw new FireflyException(trans('api.error_no_access')); // @codeCoverageIgnore
+                    throw new FireflyException('200005: You need the "owner" role to do this.'); // @codeCoverageIgnore
                 }
 
                 return $next($request);
diff --git a/app/Api/V1/Controllers/CurrencyController.php b/app/Api/V1/Controllers/CurrencyController.php
index 550820bcf6..3f1114361a 100644
--- a/app/Api/V1/Controllers/CurrencyController.php
+++ b/app/Api/V1/Controllers/CurrencyController.php
@@ -313,10 +313,10 @@ class CurrencyController extends Controller
 
         if (!$this->userRepository->hasRole($admin, 'owner')) {
             // access denied:
-            throw new FireflyException(trans('api.error_no_access_ownership')); // @codeCoverageIgnore
+            throw new FireflyException('200005: You need the "owner" role to do this.'); // @codeCoverageIgnore
         }
         if ($this->repository->currencyInUse($currency)) {
-            throw new FireflyException(trans('api.error_no_access_currency_in_use')); // @codeCoverageIgnore
+            throw new FireflyException('200006: Currency in use.'); // @codeCoverageIgnore
         }
         $this->repository->destroy($currency);
 
@@ -574,26 +574,21 @@ class CurrencyController extends Controller
     public function store(CurrencyRequest $request): JsonResponse
     {
         $currency = $this->repository->store($request->getAll());
-
-        if (null !== $currency) {
-            if (true === $request->boolean('default')) {
-                app('preferences')->set('currencyPreference', $currency->code);
-                app('preferences')->mark();
-            }
-            $manager         = $this->getManager();
-            $defaultCurrency = app('amount')->getDefaultCurrencyByUser(auth()->user());
-            $this->parameters->set('defaultCurrency', $defaultCurrency);
-
-            /** @var CurrencyTransformer $transformer */
-            $transformer = app(CurrencyTransformer::class);
-            $transformer->setParameters($this->parameters);
-
-            $resource = new Item($currency, $transformer, 'currencies');
-
-            return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
+        if (true === $request->boolean('default')) {
+            app('preferences')->set('currencyPreference', $currency->code);
+            app('preferences')->mark();
         }
-        throw new FireflyException(trans('api.error_store_new_currency')); // @codeCoverageIgnore
+        $manager         = $this->getManager();
+        $defaultCurrency = app('amount')->getDefaultCurrencyByUser(auth()->user());
+        $this->parameters->set('defaultCurrency', $defaultCurrency);
 
+        /** @var CurrencyTransformer $transformer */
+        $transformer = app(CurrencyTransformer::class);
+        $transformer->setParameters($this->parameters);
+
+        $resource = new Item($currency, $transformer, 'currencies');
+
+        return response()->json($manager->createData($resource)->toArray())->header('Content-Type', 'application/vnd.api+json');
     }
 
     /**
diff --git a/app/Factory/BillFactory.php b/app/Factory/BillFactory.php
index f958dfa7d4..3977712c6e 100644
--- a/app/Factory/BillFactory.php
+++ b/app/Factory/BillFactory.php
@@ -24,10 +24,12 @@ declare(strict_types=1);
 
 namespace FireflyIII\Factory;
 
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Bill;
 use FireflyIII\Models\TransactionCurrency;
 use FireflyIII\Services\Internal\Support\BillServiceTrait;
 use FireflyIII\User;
+use Illuminate\Database\QueryException;
 use Log;
 
 /**
@@ -55,6 +57,7 @@ class BillFactory
      * @param array $data
      *
      * @return Bill|null
+     * @throws FireflyException
      */
     public function create(array $data): ?Bill
     {
@@ -64,28 +67,31 @@ class BillFactory
         $currency = $factory->find((int)($data['currency_id'] ?? null), (string)($data['currency_code'] ?? null));
 
         if (null === $currency) {
-            // use default currency:
             $currency = app('amount')->getDefaultCurrencyByUser($this->user);
         }
+        try {
+            /** @var Bill $bill */
+            $bill = Bill::create(
+                [
+                    'name'                    => $data['name'],
+                    'match'                   => 'MIGRATED_TO_RULES',
+                    'amount_min'              => $data['amount_min'],
+                    'user_id'                 => $this->user->id,
+                    'transaction_currency_id' => $currency->id,
+                    'amount_max'              => $data['amount_max'],
+                    'date'                    => $data['date'],
+                    'repeat_freq'             => $data['repeat_freq'],
+                    'skip'                    => $data['skip'],
+                    'automatch'               => true,
+                    'active'                  => $data['active'] ?? true,
+                ]
+            );
+        } catch(QueryException $e) {
+            Log::error($e->getMessage());
+            Log::error($e->getTraceAsString());
+            throw new FireflyException('400000: Could not store bill.');
+        }
 
-        /** @var Bill $bill */
-        $bill = Bill::create(
-            [
-                'name'                    => $data['name'],
-                'match'                   => 'MIGRATED_TO_RULES',
-                'amount_min'              => $data['amount_min'],
-                'user_id'                 => $this->user->id,
-                'transaction_currency_id' => $currency->id,
-                'amount_max'              => $data['amount_max'],
-                'date'                    => $data['date'],
-                'repeat_freq'             => $data['repeat_freq'],
-                'skip'                    => $data['skip'],
-                'automatch'               => true,
-                'active'                  => $data['active'] ?? true,
-            ]
-        );
-
-        // update note:
         if (isset($data['notes'])) {
             $this->updateNote($bill, $data['notes']);
         }
diff --git a/app/Factory/CategoryFactory.php b/app/Factory/CategoryFactory.php
index b8690a04b6..da7396c8c4 100644
--- a/app/Factory/CategoryFactory.php
+++ b/app/Factory/CategoryFactory.php
@@ -24,8 +24,10 @@ declare(strict_types=1);
 namespace FireflyIII\Factory;
 
 
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Category;
 use FireflyIII\User;
+use Illuminate\Database\QueryException;
 use Log;
 
 /**
@@ -62,7 +64,7 @@ class CategoryFactory
      * @param null|string $categoryName
      *
      * @return Category|null
-     *
+     * @throws FireflyException
      */
     public function findOrCreate(?int $categoryId, ?string $categoryName): ?Category
     {
@@ -88,13 +90,17 @@ class CategoryFactory
             if (null !== $category) {
                 return $category;
             }
-
-            return Category::create(
-                [
-                    'user_id' => $this->user->id,
-                    'name'    => $categoryName,
-                ]
-            );
+            try {
+                return Category::create(
+                    [
+                        'user_id' => $this->user->id,
+                        'name'    => $categoryName,
+                    ]
+                );
+            } catch (QueryException $e) {
+                Log::error($e->getMessage());
+                throw new FireflyException('400003: Could not store new category.');
+            }
         }
 
         return null;
diff --git a/app/Factory/TransactionCurrencyFactory.php b/app/Factory/TransactionCurrencyFactory.php
index 52d1fa42aa..824046331c 100644
--- a/app/Factory/TransactionCurrencyFactory.php
+++ b/app/Factory/TransactionCurrencyFactory.php
@@ -27,6 +27,7 @@ declare(strict_types=1);
 
 namespace FireflyIII\Factory;
 
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\TransactionCurrency;
 use Illuminate\Database\QueryException;
 use Log;
@@ -51,9 +52,10 @@ class TransactionCurrencyFactory
     /**
      * @param array $data
      *
-     * @return TransactionCurrency|null
+     * @return TransactionCurrency
+     * @throws FireflyException
      */
-    public function create(array $data): ?TransactionCurrency
+    public function create(array $data): TransactionCurrency
     {
         try {
             /** @var TransactionCurrency $currency */
@@ -69,6 +71,7 @@ class TransactionCurrencyFactory
         } catch (QueryException $e) {
             $result = null;
             Log::error(sprintf('Could not create new currency: %s', $e->getMessage()));
+            throw new FireflyException('400004: Could not store new currency.');
         }
 
         return $result;
diff --git a/app/Repositories/Bill/BillRepository.php b/app/Repositories/Bill/BillRepository.php
index 2b19fb0413..8290c8479c 100644
--- a/app/Repositories/Bill/BillRepository.php
+++ b/app/Repositories/Bill/BillRepository.php
@@ -24,6 +24,7 @@ namespace FireflyIII\Repositories\Bill;
 
 use Carbon\Carbon;
 use DB;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Factory\BillFactory;
 use FireflyIII\Models\Bill;
 use FireflyIII\Models\Note;
@@ -662,9 +663,10 @@ class BillRepository implements BillRepositoryInterface
     /**
      * @param array $data
      *
-     * @return Bill|null
+     * @return Bill
+     * @throws FireflyException
      */
-    public function store(array $data): ?Bill
+    public function store(array $data): Bill
     {
         /** @var BillFactory $factory */
         $factory = app(BillFactory::class);
diff --git a/app/Repositories/Bill/BillRepositoryInterface.php b/app/Repositories/Bill/BillRepositoryInterface.php
index 6df333e44a..886816c0c2 100644
--- a/app/Repositories/Bill/BillRepositoryInterface.php
+++ b/app/Repositories/Bill/BillRepositoryInterface.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 namespace FireflyIII\Repositories\Bill;
 
 use Carbon\Carbon;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Bill;
 use FireflyIII\User;
 use Illuminate\Pagination\LengthAwarePaginator;
@@ -266,9 +267,10 @@ interface BillRepositoryInterface
     /**
      * @param array $data
      *
-     * @return Bill|null
+     * @return Bill
+     * @throws FireflyException
      */
-    public function store(array $data): ?Bill;
+    public function store(array $data): Bill;
 
     /**
      * @param Bill  $bill
diff --git a/app/Repositories/Budget/BudgetRepository.php b/app/Repositories/Budget/BudgetRepository.php
index 453e437e88..b89c8b28f2 100644
--- a/app/Repositories/Budget/BudgetRepository.php
+++ b/app/Repositories/Budget/BudgetRepository.php
@@ -25,6 +25,7 @@ namespace FireflyIII\Repositories\Budget;
 use Carbon\Carbon;
 use DB;
 use Exception;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Budget;
 use FireflyIII\Models\BudgetLimit;
 use FireflyIII\Models\RecurrenceTransactionMeta;
@@ -32,6 +33,7 @@ use FireflyIII\Models\RuleAction;
 use FireflyIII\Models\RuleTrigger;
 use FireflyIII\Services\Internal\Destroy\BudgetDestroyService;
 use FireflyIII\User;
+use Illuminate\Database\QueryException;
 use Illuminate\Support\Collection;
 use Log;
 
@@ -269,16 +271,20 @@ class BudgetRepository implements BudgetRepositoryInterface
      * @param array $data
      *
      * @return Budget
+     * @throws FireflyException
      */
     public function store(array $data): Budget
     {
-        $newBudget = new Budget(
-            [
-                'user_id' => $this->user->id,
-                'name'    => $data['name'],
-            ]
-        );
-        $newBudget->save();
+        try {
+            $newBudget = Budget::create(
+                [
+                    'user_id' => $this->user->id,
+                    'name'    => $data['name'],
+                ]
+            );
+        } catch(QueryException $e) {
+            throw new FireflyException('400002: Could not store budget.');
+        }
 
         return $newBudget;
     }
diff --git a/app/Repositories/Budget/BudgetRepositoryInterface.php b/app/Repositories/Budget/BudgetRepositoryInterface.php
index 90e5a4a6de..d92d8079f2 100644
--- a/app/Repositories/Budget/BudgetRepositoryInterface.php
+++ b/app/Repositories/Budget/BudgetRepositoryInterface.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 namespace FireflyIII\Repositories\Budget;
 
 use Carbon\Carbon;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Budget;
 use FireflyIII\User;
 use Illuminate\Support\Collection;
@@ -132,6 +133,7 @@ interface BudgetRepositoryInterface
      * @param array $data
      *
      * @return Budget
+     * @throws FireflyException
      */
     public function store(array $data): Budget;
 
diff --git a/app/Repositories/Category/CategoryRepository.php b/app/Repositories/Category/CategoryRepository.php
index f1f20c0427..ccedd6475f 100644
--- a/app/Repositories/Category/CategoryRepository.php
+++ b/app/Repositories/Category/CategoryRepository.php
@@ -24,6 +24,7 @@ namespace FireflyIII\Repositories\Category;
 
 use Carbon\Carbon;
 use DB;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Factory\CategoryFactory;
 use FireflyIII\Models\Category;
 use FireflyIII\Models\RecurrenceTransactionMeta;
@@ -239,6 +240,7 @@ class CategoryRepository implements CategoryRepositoryInterface
      * @param array $data
      *
      * @return Category
+     * @throws FireflyException
      */
     public function store(array $data): Category
     {
@@ -246,7 +248,13 @@ class CategoryRepository implements CategoryRepositoryInterface
         $factory = app(CategoryFactory::class);
         $factory->setUser($this->user);
 
-        return $factory->findOrCreate(null, $data['name']);
+        $category = $factory->findOrCreate(null, $data['name']);
+
+        if (null === $category) {
+            throw new FireflyException(sprintf('400003: Could not store new category with name "%s"', $data['name']));
+        }
+        return $category;
+
     }
 
     /**
diff --git a/app/Repositories/Category/CategoryRepositoryInterface.php b/app/Repositories/Category/CategoryRepositoryInterface.php
index a72f520223..443fb227a5 100644
--- a/app/Repositories/Category/CategoryRepositoryInterface.php
+++ b/app/Repositories/Category/CategoryRepositoryInterface.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 namespace FireflyIII\Repositories\Category;
 
 use Carbon\Carbon;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Models\Category;
 use FireflyIII\User;
 use Illuminate\Support\Collection;
@@ -117,7 +118,7 @@ interface CategoryRepositoryInterface
 
     /**
      * @param array $data
-     *
+     * @throws FireflyException
      * @return Category
      */
     public function store(array $data): Category;
diff --git a/app/Repositories/Currency/CurrencyRepository.php b/app/Repositories/Currency/CurrencyRepository.php
index ddbc21e05e..1a763ccd67 100644
--- a/app/Repositories/Currency/CurrencyRepository.php
+++ b/app/Repositories/Currency/CurrencyRepository.php
@@ -23,6 +23,7 @@ declare(strict_types=1);
 namespace FireflyIII\Repositories\Currency;
 
 use Carbon\Carbon;
+use FireflyIII\Exceptions\FireflyException;
 use FireflyIII\Factory\TransactionCurrencyFactory;
 use FireflyIII\Models\AccountMeta;
 use FireflyIII\Models\AvailableBudget;
@@ -489,14 +490,20 @@ class CurrencyRepository implements CurrencyRepositoryInterface
     /**
      * @param array $data
      *
-     * @return TransactionCurrency|null
+     * @return TransactionCurrency
+     * @throws FireflyException
      */
-    public function store(array $data): ?TransactionCurrency
+    public function store(array $data): TransactionCurrency
     {
         /** @var TransactionCurrencyFactory $factory */
         $factory = app(TransactionCurrencyFactory::class);
+        $result  = $factory->create($data);
 
-        return $factory->create($data);
+        if (null === $result) {
+            throw new FireflyException('400004: Could not store new currency.');
+        }
+
+        return $result;
     }
 
     /**
diff --git a/app/Repositories/Currency/CurrencyRepositoryInterface.php b/app/Repositories/Currency/CurrencyRepositoryInterface.php
index d5e850be84..1853e45106 100644
--- a/app/Repositories/Currency/CurrencyRepositoryInterface.php
+++ b/app/Repositories/Currency/CurrencyRepositoryInterface.php
@@ -234,9 +234,9 @@ interface CurrencyRepositoryInterface
     /**
      * @param array $data
      *
-     * @return TransactionCurrency|null
+     * @return TransactionCurrency
      */
-    public function store(array $data): ?TransactionCurrency;
+    public function store(array $data): TransactionCurrency;
 
     /**
      * @param TransactionCurrency $currency