Agent skill
replit-hello-world
Create a minimal working Replit app with database, object storage, and auth. Use when starting a new Replit project, testing your setup, or learning Replit's built-in services (DB, Auth, Object Storage). Trigger with phrases like "replit hello world", "replit starter", "replit quick start", "first replit app", "replit example".
Install this agent skill to your Project
npx add-skill https://github.com/jeremylongshore/claude-code-plugins-plus-skills/tree/main/plugins/saas-packs/replit-pack/skills/replit-hello-world
SKILL.md
Replit Hello World
Overview
Build a working Replit app that demonstrates core platform services: Express/Flask server, Replit Database (key-value store), Object Storage (file uploads), Auth (user login), and PostgreSQL. Produces a running app you can deploy.
Prerequisites
- Replit App created (template or blank)
.replitandreplit.nixconfigured (seereplit-install-auth)- Node.js 18+ or Python 3.10+
Instructions
Step 1: Node.js — Express + Replit Database
// index.ts
import express from 'express';
import Database from '@replit/database';
const app = express();
const db = new Database();
app.use(express.json());
// Health check with Replit env vars
app.get('/health', (req, res) => {
res.json({
status: 'ok',
repl: process.env.REPL_SLUG,
owner: process.env.REPL_OWNER,
timestamp: new Date().toISOString(),
});
});
// Replit Key-Value Database CRUD
// Limits: 50 MiB total, 5,000 keys, 1 KB per key, 5 MiB per value
app.post('/api/items', async (req, res) => {
const { key, value } = req.body;
await db.set(key, value);
res.json({ stored: key });
});
app.get('/api/items/:key', async (req, res) => {
const value = await db.get(req.params.key);
if (value === null) return res.status(404).json({ error: 'Not found' });
res.json({ key: req.params.key, value });
});
app.get('/api/items', async (req, res) => {
const prefix = (req.query.prefix as string) || '';
const keys = await db.list(prefix);
res.json({ keys });
});
app.delete('/api/items/:key', async (req, res) => {
await db.delete(req.params.key);
res.json({ deleted: req.params.key });
});
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`Server running on port ${PORT}`);
console.log(`Repl: ${process.env.REPL_SLUG} by ${process.env.REPL_OWNER}`);
});
package.json dependencies:
{
"dependencies": {
"@replit/database": "^2.0.0",
"express": "^4.18.0"
},
"devDependencies": {
"@types/express": "^4.17.0",
"typescript": "^5.0.0"
}
}
Step 2: Python — Flask + Replit Database
# main.py
from flask import Flask, request, jsonify
from replit import db
import os
app = Flask(__name__)
@app.route('/health')
def health():
return jsonify({
'status': 'ok',
'repl': os.environ.get('REPL_SLUG'),
'owner': os.environ.get('REPL_OWNER'),
})
# Replit DB works like a Python dict
@app.route('/api/items', methods=['POST'])
def create_item():
data = request.json
db[data['key']] = data['value']
return jsonify({'stored': data['key']})
@app.route('/api/items/<key>')
def get_item(key):
if key not in db:
return jsonify({'error': 'Not found'}), 404
return jsonify({'key': key, 'value': db[key]})
@app.route('/api/items')
def list_items():
prefix = request.args.get('prefix', '')
keys = db.prefix(prefix) if prefix else list(db.keys())
return jsonify({'keys': keys})
@app.route('/api/items/<key>', methods=['DELETE'])
def delete_item(key):
if key in db:
del db[key]
return jsonify({'deleted': key})
if __name__ == '__main__':
app.run(host='0.0.0.0', port=int(os.environ.get('PORT', 3000)))
Step 3: Add Object Storage (File Uploads)
// storage.ts — Replit Object Storage (App Storage)
import { Client } from '@replit/object-storage';
const storage = new Client();
// Upload text content
await storage.uploadFromText('notes/hello.txt', 'Hello from Replit!');
// Upload from file on disk
await storage.uploadFromFilename('uploads/photo.jpg', '/tmp/photo.jpg');
// Download as text
const { value } = await storage.downloadAsText('notes/hello.txt');
console.log(value); // "Hello from Replit!"
// Download as bytes
const { value: bytes } = await storage.downloadAsBytes('uploads/photo.jpg');
// List objects with prefix
const objects = await storage.list({ prefix: 'notes/' });
for (const obj of objects) {
console.log(obj.name); // "notes/hello.txt"
}
// Check existence
const { exists } = await storage.exists('notes/hello.txt');
// Copy object
await storage.copy('notes/hello.txt', 'archive/hello-backup.txt');
// Delete object
await storage.delete('notes/hello.txt');
Python Object Storage:
from replit.object_storage import Client
storage = Client()
# Upload text
storage.upload_from_text('notes/hello.txt', 'Hello from Replit!')
# Download
content = storage.download_as_text('notes/hello.txt')
# List with prefix
objects = storage.list(prefix='notes/')
# Delete
storage.delete('notes/hello.txt')
# Check existence
exists = storage.exists('notes/hello.txt')
Step 4: Add Auth-Protected Route
// Add to index.ts
app.get('/api/me', (req, res) => {
const userId = req.headers['x-replit-user-id'];
if (!userId) return res.status(401).json({ error: 'Login required' });
res.json({
id: userId,
name: req.headers['x-replit-user-name'],
image: req.headers['x-replit-user-profile-image'],
});
});
// Client-side: fetch('/__replauthuser') returns current user
Step 5: .replit for This App
entrypoint = "index.ts"
run = "npx tsx index.ts"
modules = ["nodejs-20:v8-20230920-bd784b9"]
[nix]
channel = "stable-24_05"
[env]
PORT = "3000"
[deployment]
run = ["sh", "-c", "npx tsx index.ts"]
deploymentTarget = "autoscale"
Output
After running, verify at these endpoints:
GET /health— returns Repl metadataPOST /api/items— stores key-value dataGET /api/items?prefix=— lists keysGET /api/me— returns authenticated user (when deployed)
Error Handling
| Error | Cause | Solution |
|---|---|---|
Cannot find module '@replit/database' |
Not installed | npm install @replit/database |
db.set is not a function |
Wrong import | Use new Database() not import db |
REPLIT_DB_URL undefined |
Not on Replit | DB only available inside a Repl |
| Object Storage 403 | No bucket provisioned | Create bucket in Object Storage pane |
| Auth headers empty | Running in dev | Auth works only on deployed .replit.app |
Resources
Next Steps
Deploy with replit-deploy-integration or add PostgreSQL with replit-data-handling.
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