I chose a familiar environment for my comparison: a new NestJS<\/a> project from scratch.<\/p>\n\n\n\n For my project, I want to:<\/p>\n\n\n\n To help me, I’m going to use the GitHub Copilot<\/a> agent with the GTP5-mini model. I’ll ask it to generate code on my behalf, as much as possible. However, I’ll continue to follow NestJS best practices by using the documentation recommendations and initializing the project myself. I will focus on prompting, initializing the context and reviewing the code generated by the AI.<\/p>\n\n\n\n For better results, I will develop the application step by step and control the generated code at each step.<\/p>\n\n\n\n At first, I initialize a new NestJS project using the CLI, as mentioned in the documentation:<\/p>\n\n\n\n I start by opening the project in VSCode and I open a new chat with the AI agent. I’m trying to give it some general instructions for the rest of the tasks:<\/p>\n\n\n\n The AI agent discovers the project:<\/p>\n\n\n\n I followed the documentation to add configuration<\/a> support using .env files<\/p>\n\n\n\n I’ve manually added the required package:<\/p>\n\n\n\n And asked the AI to generate the code:<\/p>\n\n\n\n I want to use TypeORM<\/a> to manage my database connections and migrations.<\/p>\n\n\n\n First, I install the required packages:<\/p>\n\n\n\n And then ask the AI agent to generate the code:<\/p>\n\n\n\n Note<\/strong> : Be careful when you send credentials to AI<\/p>\n\n\n\n Next request to the AI agent: create a migration to initialize the database schema:<\/p>\n\n\n\n In addition, in my package.json, the agent adds the migration command to npm in the project:<\/p>\n\n\n\n To simplify the process, I asked the AI agent to generate a default user for my application:<\/p>\n\n\n\n After the completion by the AI agent, I run the migration.<\/p>\n\n\n\n Now, I ask the agent to create the users module with detailed endpoints:<\/p>\n\n\n\n This step is very quick, and the code is generated in 4min only !<\/p>\n\n\n\n To test the first REST module, I ask the AI to add Swagger UI<\/a> to the project.<\/p>\n\n\n\n As with the other steps, I add the packages myself:<\/p>\n\n\n\n Note:<\/strong> This step is very tricky for the AI, if you don’t specify the already installed package, it will try to install an outdated version.<\/p>\n\n\n\n Then, I ask the AI agent to generate the code:<\/p>\n\n\n\n In few minutes, we have the API documentation:<\/p>\n\n\n\n During API testing, I noticed that the password hash was returned in the user list. However, initially, I had instructed the AI \u200b\u200bto follow security best practices…<\/p>\n\n\n\n I asked the AI agent to fix this issue:<\/p>\n\n\n\n As authentication mechanism, I use JWT<\/a> tokens provided by passport<\/a> library.<\/p>\n\n\n\n I install the required packages:<\/p>\n\n\n\n Then, I ask the AI agent to generate the code:<\/p>\n\n\n\n And I instruct the AI to use .env file for the JWT secret and expiration:<\/p>\n\n\n\n Now, I want to secure the users endpoints to allow only authenticated users and ask the agent the following:<\/p>\n\n\n\n Last point, I want to be able to authenticate on the Swagger interface, so I ask it:<\/p>\n\n\n\n All of this took me around 1h30<\/strong> to complete, including prompting and reviewing the steps.<\/p>\n\n\n\n Reading the documentation, understanding the technologies, adding the dependancies remained the same.<\/p>\n\n\n\n The initial estimate, without AI, was between 2 and 4 hours to complete the project :<\/p>\n\n\n\n During development, AI makes certain errors or inaccuracies like TypeScripts compilation errors, password or security issues such as returning the password hash in the user list. However, the time spent to review and correct these issues is largely compensated by the speed of code generation.<\/p>\n\n\n\n At the end, coding with AI is very fast, the generated code with a well documented technology (NestJS) is good.<\/p>\n\n\n\n Even if formulating a clear request requires careful consideration and wording, coding is comfortable. However, the job is no longer the same; it now requires good code planning and architecture and the ability to review the generated code. Coding with AI can be effective, but only if you have a clear idea of what you want from the very beginning, use clear instructions and leave no room for interpretation by the AI.<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" In this article, I will try to evaluate the benefits of AI on a development project and what concrete changes it makes to our development practices. The test case and the approach I chose a familiar environment for my comparison: a new NestJS project from scratch. For my project, I want to: To help me, […]<\/p>\n","protected":false},"author":72,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[368,3029],"tags":[3753,3257],"type_dbi":[],"class_list":["post-41782","post","type-post","status-publish","format-standard","hentry","category-development-performance","category-web","tag-nestjs","tag-typescript"],"acf":[],"yoast_head":"\n\n
Intialize the project<\/strong><\/h2>\n\n\n\n
npm i -g @nestjs\/cli\nnest new nestjs-project<\/code><\/pre>\n\n\n\nFirst contact with the AI agent<\/strong><\/h2>\n\n\n\n
Remember:\n- You are a full-stack TypeScript developer.\n- You follow best practices in development and security.\n- You will be working on this NestJS project.<\/code><\/pre>\n\n\n\n![\"\"](\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2025\/12\/VsCode-1024x574.png\")
<\/figure>\n\n\n\nFirst Task, add application configuration<\/strong><\/h2>\n\n\n\n
npm i --save @nestjs\/config<\/code><\/pre>\n\n\n\n@nestjs\/config is installed. Add support for .env in the application. The config file must contain the credentials to access to the database (host, database name, user, password).<\/code><\/pre>\n\n\n\nSecond Task, connect to the database and create the users table<\/strong><\/h2>\n\n\n\n
npm install --save @nestjs\/typeorm typeorm pg<\/code><\/pre>\n\n\n\nI will use typeorm and postgres. Connect the application to the database.\nSave the credentials in the .env file.\nUse the credentials:\n- host: localhost\n- name: nestjs, \n- user: nest-user \n- password XXX<\/code><\/pre>\n\n\n\nAdd a migration to create a \"users\" table with the following fields: id (primary key), username (string), email (string), password (string), is_admin (boolean), disabled (boolean), created_at (timestamp), updated_at (timestamp).<\/code><\/pre>\n\n\n\n \"typeorm:migration:run\": \"ts-node -r tsconfig-paths\/register .\/node_modules\/typeorm\/cli.js migration:run -d .\/data-source.ts\",<\/code><\/pre>\n\n\n\nIn the migration, add a default admin user with the following values:\n username: \"admin\"\n email: \"admin@example.com\"\n password: \"Admin@123\" (hash the password using bcrypt)\n is_admin: true\n disabled: false<\/code><\/pre>\n\n\n\nFirst module, service and controller for users with CRUD endpoints<\/strong><\/h2>\n\n\n\n
Add a module, service, and controller for \"users\" with the following endpoints:\n- GET \/users: Retrieve a list of all users.\n- GET \/users\/:id: Retrieve a user by ID.\n- POST \/users: Create a new user.\n- PUT \/users\/:id: Update a user by ID.\n- DELETE \/users\/:id: Delete a user by ID.<\/code><\/pre>\n\n\n\nAdd Swagger documentation<\/strong><\/h2>\n\n\n\n
npm install --save @nestjs\/swagger<\/code><\/pre>\n\n\n\n@nestjs\/swagger is installed\nAdd swagger to the application. \nDocument the users endpoints.<\/code><\/pre>\n\n\n\n![\"\"](\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2025\/12\/Swagger-UI-1024x610.png\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2025\/12\/Password-Hash-1024x580.png\")
<\/figure>\n\n\n\nThe users password field must be excluded from the responses.<\/code><\/pre>\n\n\n\nLast task, add JWT authentication<\/h2>\n\n\n\n
npm install --save @nestjs\/passport\nnpm install --save @nestjs\/jwt passport-jwt\nnpm install --save-dev @types\/passport-jwt<\/code><\/pre>\n\n\n\nImplement the JWT authentication strategy, @nestjs\/jwt passport-jwt and @types\/passport-jwt are installed.\nAdd a login endpoint that returns a JWT token when provided with valid user credentials (username and password from the users table).<\/code><\/pre>\n\n\n\nAdd the JWT secrets and expiration into the .env file, Fix the typescript errors, Improve the swagger documentation for login endpoint (message definition)<\/code><\/pre>\n\n\n\nAdd a guard on the users endpoints to allow only connected users<\/code><\/pre>\n\n\n\nAdd the ability to authenticate on the Swagger interface with a bearer token.<\/code><\/pre>\n\n\n\n![\"\"](\"https:\/\/www.dbi-services.com\/blog\/wp-content\/uploads\/sites\/2\/2025\/12\/Swagger-Auth-1024x570.png\")
<\/figure>\n\n\n\nConclusion<\/strong><\/h2>\n\n\n\n
Task<\/th> Estimated Time<\/th> AI Coding \/ prompting<\/th> Review<\/th><\/tr> .env<\/td> 15\u201330 min<\/td> 6 min<\/td> 5 min<\/td><\/tr> Connexion PostgreSQL<\/td> 20\u201340 min<\/td> 4 min<\/td> 2 min<\/td><\/tr> Table User + migration<\/td> 15\u201325 min<\/td> 7 min<\/td> 2 min<\/td><\/tr> CRUD Users<\/td> 30\u201345 min<\/td> 5 min<\/td> 10 min<\/td><\/tr> Swagger UI<\/td> 15\u201330 min<\/td> 6 min<\/td> 6 min<\/td><\/tr> Auth JWT<\/td> 30\u201360 min<\/td> 12 min<\/td> 15 min<\/td><\/tr> Guards<\/td> 15\u201330 min<\/td> 5 min<\/td> 5 min<\/td><\/tr> TOTAL<\/strong><\/td> 2h20 \u2013 4h20<\/td> 45min<\/td> 45 min<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n