diff --git a/apps/api/src/lib/errors/error-builder.ts b/apps/api/src/lib/errors/error-builder.ts
new file mode 100644
index 0000000..9de1612
--- /dev/null
+++ b/apps/api/src/lib/errors/error-builder.ts
@@ -0,0 +1,520 @@
+import {
+  BadRequestException,
+  ConflictException,
+  ForbiddenException,
+  GoneException,
+  HttpException,
+  HttpStatus,
+  InternalServerErrorException,
+  MethodNotAllowedException,
+  NotAcceptableException,
+  NotFoundException,
+  NotImplementedException,
+  PayloadTooLargeException,
+  PreconditionFailedException,
+  RequestTimeoutException,
+  ServiceUnavailableException,
+  UnauthorizedException,
+  UnprocessableEntityException,
+  UnsupportedMediaTypeException,
+} from '@nestjs/common';
+
+/**
+ * Centralized error builder with comprehensive error handling capabilities.
+ *
+ * @example
+ * // Basic usage
+ * ErrorBuilder.notFound('User not found');
+ *
+ * @example
+ * // Conditional throwing
+ * ErrorBuilder.throwIf(!user, () => ErrorBuilder.notFound('User not found'));
+ *
+ */
+export class ErrorBuilder {
+  // ============================================================================
+  // STANDARD HTTP ERRORS (4xx - Client Errors)
+  // ============================================================================
+
+  /**
+   * Throws a 400 Bad Request exception
+   * @param message - Error message describing the bad request
+   */
+  static badRequest(message: string): never {
+    throw new BadRequestException(message);
+  }
+
+  /**
+   * Throws a 401 Unauthorized exception
+   * @param message - Error message describing the authorization failure
+   */
+  static unauthorized(message: string): never {
+    throw new UnauthorizedException(message);
+  }
+
+  /**
+   * Throws a 402 Payment Required exception
+   * @param message - Error message describing payment requirement
+   */
+  static paymentRequired(message: string): never {
+    throw new HttpException(message, HttpStatus.PAYMENT_REQUIRED);
+  }
+
+  /**
+   * Throws a 403 Forbidden exception
+   * @param message - Error message describing why access is forbidden
+   */
+  static forbidden(message: string): never {
+    throw new ForbiddenException(message);
+  }
+
+  /**
+   * Throws a 404 Not Found exception
+   * @param message - Error message describing what was not found
+   */
+  static notFound(message: string): never {
+    throw new NotFoundException(message);
+  }
+
+  /**
+   * Throws a 405 Method Not Allowed exception
+   * @param message - Error message describing the method not allowed
+   */
+  static methodNotAllowed(message: string): never {
+    throw new MethodNotAllowedException(message);
+  }
+
+  /**
+   * Throws a 406 Not Acceptable exception
+   * @param message - Error message describing the not acceptable content
+   */
+  static notAcceptable(message: string): never {
+    throw new NotAcceptableException(message);
+  }
+
+  /**
+   * Throws a 407 Proxy Authentication Required exception
+   * @param message - Error message describing proxy authentication requirement
+   */
+  static proxyAuthRequired(message: string): never {
+    throw new HttpException(message, HttpStatus.PROXY_AUTHENTICATION_REQUIRED);
+  }
+
+  /**
+   * Throws a 408 Request Timeout exception
+   * @param message - Error message describing the timeout
+   */
+  static requestTimeout(message: string): never {
+    throw new RequestTimeoutException(message);
+  }
+
+  /**
+   * Throws a 409 Conflict exception
+   * @param message - Error message describing the conflict
+   */
+  static conflict(message: string): never {
+    throw new ConflictException(message);
+  }
+
+  /**
+   * Throws a 410 Gone exception
+   * @param message - Error message describing what is gone
+   */
+  static gone(message: string): never {
+    throw new GoneException(message);
+  }
+
+  /**
+   * Throws a 411 Length Required exception
+   * @param message - Error message describing length requirement
+   */
+  static lengthRequired(message: string): never {
+    throw new HttpException(message, HttpStatus.LENGTH_REQUIRED);
+  }
+
+  /**
+   * Throws a 412 Precondition Failed exception
+   * @param message - Error message describing the failed precondition
+   */
+  static preconditionFailed(message: string): never {
+    throw new PreconditionFailedException(message);
+  }
+
+  /**
+   * Throws a 413 Payload Too Large exception
+   * @param message - Error message describing the payload size issue
+   */
+  static payloadTooLarge(message: string): never {
+    throw new PayloadTooLargeException(message);
+  }
+
+  /**
+   * Throws a 414 URI Too Long exception
+   * @param message - Error message describing URI length issue
+   */
+  static uriTooLong(message: string): never {
+    throw new HttpException(message, HttpStatus.URI_TOO_LONG);
+  }
+
+  /**
+   * Throws a 415 Unsupported Media Type exception
+   * @param message - Error message describing the unsupported media type
+   */
+  static unsupportedMediaType(message: string): never {
+    throw new UnsupportedMediaTypeException(message);
+  }
+
+  /**
+   * Throws a 416 Range Not Satisfiable exception
+   * @param message - Error message describing range issue
+   */
+  static rangeNotSatisfiable(message: string): never {
+    throw new HttpException(
+      message,
+      HttpStatus.REQUESTED_RANGE_NOT_SATISFIABLE,
+    );
+  }
+
+  /**
+   * Throws a 417 Expectation Failed exception
+   * @param message - Error message describing expectation failure
+   */
+  static expectationFailed(message: string): never {
+    throw new HttpException(message, HttpStatus.EXPECTATION_FAILED);
+  }
+
+  /**
+   * Throws a 418 I'm a teapot exception (Easter egg, but why not?)
+   * @param message - Error message
+   */
+  static imATeapot(message: string): never {
+    throw new HttpException(message, HttpStatus.I_AM_A_TEAPOT);
+  }
+
+  /**
+   * Throws a 421 Misdirected Request exception
+   * @param message - Error message describing misdirected request
+   */
+  static misdirected(message: string): never {
+    throw new HttpException(message, HttpStatus.MISDIRECTED);
+  }
+
+  /**
+   * Throws a 422 Unprocessable Entity exception
+   * @param message - Error message describing the unprocessable entity
+   */
+  static unprocessableEntity(message: string): never {
+    throw new UnprocessableEntityException(message);
+  }
+
+  /**
+   * Throws a 423 Locked exception
+   * @param message - Error message describing the locked resource
+   */
+  static locked(message: string): never {
+    throw new HttpException(message, HttpStatus.LOCKED);
+  }
+
+  /**
+   * Throws a 424 Failed Dependency exception
+   * @param message - Error message describing the failed dependency
+   */
+  static failedDependency(message: string): never {
+    throw new HttpException(message, HttpStatus.FAILED_DEPENDENCY);
+  }
+
+  /**
+   * Throws a 426 Upgrade Required exception
+   * @param message - Error message describing upgrade requirement
+   */
+  static upgradeRequired(message: string): never {
+    throw new HttpException(message, 426);
+  }
+
+  /**
+   * Throws a 428 Precondition Required exception
+   * @param message - Error message describing precondition requirement
+   */
+  static preconditionRequired(message: string): never {
+    throw new HttpException(message, HttpStatus.PRECONDITION_REQUIRED);
+  }
+
+  /**
+   * Throws a 429 Too Many Requests exception
+   * @param message - Error message describing rate limit
+    (consider setting retryAfter)
+   */
+  static tooManyRequests(message: string): never {
+    throw new HttpException(message, HttpStatus.TOO_MANY_REQUESTS);
+  }
+
+  /**
+   * Throws a 431 Request Header Fields Too Large exception
+   * @param message - Error message describing header size issue
+   */
+  static headersTooLarge(message: string): never {
+    throw new HttpException(message, 431);
+  }
+
+  /**
+   * Throws a 451 Unavailable For Legal Reasons exception
+   * @param message - Error message describing legal restriction
+   */
+  static unavailableForLegalReasons(message: string): never {
+    throw new HttpException(message, 451);
+  }
+
+  // ============================================================================
+  // STANDARD HTTP ERRORS (5xx - Server Errors)
+  // ============================================================================
+
+  /**
+   * Throws a 500 Internal Server Error exception
+   * @param message - Error message describing the internal error
+   */
+  static internalError(message: string): never {
+    throw new InternalServerErrorException(message);
+  }
+
+  /**
+   * Throws a 501 Not Implemented exception
+   * @param message - Error message describing what's not implemented
+   */
+  static notImplemented(message: string): never {
+    throw new NotImplementedException(message);
+  }
+
+  /**
+   * Throws a 502 Bad Gateway exception
+   * @param message - Error message describing the bad gateway
+   */
+  static badGateway(message: string): never {
+    throw new HttpException(message, HttpStatus.BAD_GATEWAY);
+  }
+
+  /**
+   * Throws a 503 Service Unavailable exception
+   * @param message - Error message describing service unavailability
+   */
+  static serviceUnavailable(message: string): never {
+    throw new ServiceUnavailableException(message);
+  }
+
+  /**
+   * Throws a 504 Gateway Timeout exception
+   * @param message - Error message describing the gateway timeout
+   */
+  static gatewayTimeout(message: string): never {
+    throw new HttpException(message, HttpStatus.GATEWAY_TIMEOUT);
+  }
+
+  /**
+   * Throws a 505 HTTP Version Not Supported exception
+   * @param message - Error message describing HTTP version issue
+   */
+  static httpVersionNotSupported(message: string): never {
+    throw new HttpException(message, HttpStatus.HTTP_VERSION_NOT_SUPPORTED);
+  }
+
+  /**
+   * Throws a 506 Variant Also Negotiates exception
+   * @param message - Error message
+   */
+  static variantAlsoNegotiates(message: string): never {
+    throw new HttpException(message, 506);
+  }
+
+  /**
+   * Throws a 507 Insufficient Storage exception
+   * @param message - Error message describing storage issue
+   */
+  static insufficientStorage(message: string): never {
+    throw new HttpException(message, HttpStatus.INSUFFICIENT_STORAGE);
+  }
+
+  /**
+   * Throws a 508 Loop Detected exception
+   * @param message - Error message describing loop detection
+   */
+  static loopDetected(message: string): never {
+    throw new HttpException(message, HttpStatus.LOOP_DETECTED);
+  }
+
+  /**
+   * Throws a 510 Not Extended exception
+   * @param message - Error message
+   */
+  static notExtended(message: string): never {
+    throw new HttpException(message, 510);
+  }
+
+  /**
+   * Throws a 511 Network Authentication Required exception
+   * @param message - Error message describing network auth requirement
+   */
+  static networkAuthRequired(message: string): never {
+    throw new HttpException(message, 511);
+  }
+
+  // ============================================================================
+  // SPECIALIZED ERROR HELPERS
+  // ============================================================================
+
+  /**
+   * Throws a database-related error
+   * @param message - Error message
+   */
+  static validationError(message: string): never {
+    throw new BadRequestException(message);
+  }
+
+  /**
+   * Throws a database-related error
+   * @param message - Error message
+   */
+  static databaseError(message: string): never {
+    throw new InternalServerErrorException(message);
+  }
+
+  /**
+   * Throws an external service error
+   * @param service - Service name
+   */
+  static externalServiceError(service: string): never {
+    throw new ServiceUnavailableException(service);
+  }
+
+  /**
+   * Throws a rate limit error
+   * @param message - Error message
+   */
+  static rateLimitExceeded(message: string): never {
+    throw new HttpException(message, HttpStatus.TOO_MANY_REQUESTS);
+  }
+
+  /**
+   * Throws a duplicate resource error
+   * @param resource - Resource name
+   * @param identifier - Optional identifier of the duplicate
+   */
+  static duplicate(resource: string, identifier?: string): never {
+    const message = identifier
+      ? `${resource} with identifier '${identifier}' already exists`
+      : `${resource} already exists`;
+
+    throw new ConflictException(message);
+  }
+
+  /**
+   * Throws a resource not found error with context
+   * @param resource - Resource name
+   * @param identifier - Optional identifier that was not found
+   */
+  static resourceNotFound(resource: string, identifier?: string): never {
+    const message = identifier
+      ? `${resource} with identifier '${identifier}' not found`
+      : `${resource} not found`;
+
+    throw new NotFoundException(message);
+  }
+
+  /**
+   * Throws a type error new TypeError(message)
+   * @param message - Error message
+   */
+  static typeMismatch(message: string): never {
+    throw new TypeError(message);
+  }
+
+  /**
+   * Throws a custom exception with any HTTP status code
+   * @param status - HTTP status code
+   * @param message - Error message
+   */
+  static customException(status: HttpStatus, message: string): never {
+    throw new HttpException(message, status);
+  }
+
+  /**
+   * Throws a custom error new Error(message)
+   * @param message - Error message
+   */
+  static customError(message: string): never {
+    throw new Error(message);
+  }
+
+  // ============================================================================
+  // CONDITIONAL ERROR THROWING
+  // ============================================================================
+
+  /**
+   * Throws an error if condition is true
+   * @param condition - Condition to check
+   * @param errorFactory - Function that throws the error
+   */
+  static throwIf(condition: boolean, errorFactory: () => never): void {
+    if (condition) {
+      errorFactory();
+    }
+  }
+
+  /**
+   * Throws an error if condition is false
+   * @param condition - Condition to check
+   * @param errorFactory - Function that throws the error
+   */
+  static throwUnless(condition: boolean, errorFactory: () => never): void {
+    if (!condition) {
+      errorFactory();
+    }
+  }
+
+  /**
+   * Throws not found if value is null or undefined
+   * @param value - Value to check
+   * @param message - Error message
+   */
+  static throwIfNotFound<T>(
+    value: T | null | undefined,
+    message: string,
+  ): asserts value is T {
+    if (value === null || value === undefined) {
+      this.notFound(message);
+    }
+  }
+
+  /**
+   * Throws forbidden if condition is true
+   * @param condition - Condition to check
+   * @param message - Error message
+   */
+  static throwIfForbidden(condition: boolean, message: string): void {
+    if (condition) {
+      this.forbidden(message);
+    }
+  }
+
+  /**
+   * Throws unauthorized if condition is true
+   * @param condition - Condition to check
+   * @param message - Error message
+   */
+  static throwIfUnauthorized(condition: boolean, message: string): void {
+    if (condition) {
+      this.unauthorized(message);
+    }
+  }
+
+  // ============================================================================
+  // ERROR WRAPPING AND TRANSFORMATION
+  // ============================================================================
+
+  /**
+   * Wraps an unknown error into a structured error
+   * @param error - The original error
+   */
+  static wrap(error: unknown): never {
+    const cause = error instanceof Error ? error : new Error(String(error));
+    throw new InternalServerErrorException(cause);
+  }
+}
diff --git a/apps/api/src/lib/errors/index.ts b/apps/api/src/lib/errors/index.ts
new file mode 100644
index 0000000..c008d35
--- /dev/null
+++ b/apps/api/src/lib/errors/index.ts
@@ -0,0 +1 @@
+export { ErrorBuilder } from './error-builder';
diff --git a/apps/api/src/modules/auth/auth.service.ts b/apps/api/src/modules/auth/auth.service.ts
index 09b50a5..6835f54 100644
--- a/apps/api/src/modules/auth/auth.service.ts
+++ b/apps/api/src/modules/auth/auth.service.ts
@@ -7,6 +7,7 @@ import { createBetterAuth } from './auth';
 import { AppContextType } from '../../app.context';
 import { fromNodeHeaders } from 'better-auth/node';
 import { DateExtensions, Logger } from '@repo/utils-core';
+import { ErrorBuilder } from '../../lib/errors';
 
 @Injectable()
 export class AuthService {
@@ -107,8 +108,8 @@ export class AuthService {
 
     const account = accounts.find((acc) => acc.providerId === provider);
     if (!account) {
-      throw new Error(
-        `No ${provider} account found for provider ${provider}. User may need to link their account.`,
+      return ErrorBuilder.notFound(
+        `No ${provider} account found. User may need to link their ${provider} account`,
       );
     }
 
@@ -121,8 +122,8 @@ export class AuthService {
     });
 
     if (!tokens?.accessToken) {
-      throw new Error(
-        `Failed to refresh token for user ${account.userId} and provider ${provider}. User may need to re-authenticate.`,
+      return ErrorBuilder.unauthorized(
+        `Failed to refresh ${provider} token. User may need to re-authenticate`,
       );
     }
 
diff --git a/apps/api/src/modules/crud/services/crud.mongoose.service.ts b/apps/api/src/modules/crud/services/crud.mongoose.service.ts
index 67f7b9b..501e259 100644
--- a/apps/api/src/modules/crud/services/crud.mongoose.service.ts
+++ b/apps/api/src/modules/crud/services/crud.mongoose.service.ts
@@ -1,8 +1,4 @@
-import {
-  BadRequestException,
-  Injectable,
-  NotFoundException,
-} from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import { Crud } from '../schemas/crud.schema';
 import { NoTransaction } from '../../../decorators/method/no-transaction.decorator';
 import { AutoTransaction } from '../../../decorators/class/auto-transaction.decorator';
@@ -10,6 +6,7 @@ import { ServerConstants } from '../../../constants/server.constants';
 import { Logger, StringExtensions } from '@repo/utils-core';
 import { Propagation } from '@nestjs-cls/transactional';
 import { CrudMongooseRepository } from '../repositories/mongoose/crud.mongoose-repository';
+import { ErrorBuilder } from '../../../lib/errors';
 
 @Injectable()
 @AutoTransaction(
@@ -21,7 +18,7 @@ export class CrudMongooseService {
 
   async createCrud(data: Partial<Crud>): Promise<Crud> {
     if (StringExtensions.IsNullOrEmpty(data.content)) {
-      throw new BadRequestException('Content is Empty');
+      return ErrorBuilder.validationError('Content cannot be empty');
     }
 
     const created = await this.crudRepository.create({
@@ -40,7 +37,7 @@ export class CrudMongooseService {
   @NoTransaction('dont care if transaction is broken')
   async findOne(id: string): Promise<Crud> {
     const crud = await this.crudRepository.findById(id);
-    if (!crud) throw new NotFoundException(`Crud with id ${id} not found`);
+    if (!crud) return ErrorBuilder.resourceNotFound('Crud', id);
     return crud;
   }
 
@@ -48,13 +45,13 @@ export class CrudMongooseService {
     const updated = await this.crudRepository.findByIdAndUpdate(id, {
       content: data.content,
     });
-    if (!updated) throw new NotFoundException(`Crud with id ${id} not found`);
+    if (!updated) return ErrorBuilder.resourceNotFound('Crud', id);
     return updated;
   }
 
   async delete(id: string): Promise<Crud | null> {
     const deleted = await this.crudRepository.findByIdAndDelete(id);
-    if (!deleted) throw new NotFoundException(`Crud with id ${id} not found`);
+    if (!deleted) return ErrorBuilder.resourceNotFound('Crud', id);
     Logger.instance.debug('[Mongoose] Deleted:', deleted);
     return deleted;
   }
diff --git a/apps/api/src/modules/crud/services/crud.prisma.service.ts b/apps/api/src/modules/crud/services/crud.prisma.service.ts
index ddec78d..c064028 100644
--- a/apps/api/src/modules/crud/services/crud.prisma.service.ts
+++ b/apps/api/src/modules/crud/services/crud.prisma.service.ts
@@ -1,4 +1,4 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import { Crud } from '../schemas/crud.schema';
 import { NoTransaction } from '../../../decorators/method/no-transaction.decorator';
 import { AutoTransaction } from '../../../decorators/class/auto-transaction.decorator';
@@ -6,6 +6,7 @@ import { ServerConstants } from '../../../constants/server.constants';
 import { Logger } from '@repo/utils-core';
 import { Propagation } from '@nestjs-cls/transactional';
 import { CrudPrismaRepository } from '../repositories/prisma/crud.prisma-repository';
+import { ErrorBuilder } from '../../../lib/errors';
 
 @Injectable()
 @AutoTransaction(
@@ -43,7 +44,7 @@ export class CrudPrismaService {
       where: { id },
       data: { content: data.content },
     });
-    if (!updated) throw new NotFoundException(`Crud with id ${id} not found`);
+    if (!updated) return ErrorBuilder.resourceNotFound('Crud', id);
     return updated;
   }
 
@@ -52,7 +53,7 @@ export class CrudPrismaService {
       where: { id },
     });
 
-    if (!deleted) throw new NotFoundException(`Crud with id ${id} not found`);
+    if (!deleted) return ErrorBuilder.resourceNotFound('Crud', id);
     Logger.instance.debug('[Prisma] Deleted:', deleted);
     return deleted;
   }