How to Query SQL Databases Online: Connect PostgreSQL, MySQL, MariaDB
Connect to PostgreSQL, MySQL, or MariaDB from your browser. Run SQL queries, explore schemas, and export results without installing a database client. All credentials are AES-256 encrypted.
Try the free online tool mentioned in this guide:SQL Client
Why use an online SQL client?
Database clients like DBeaver, TablePlus, and pgAdmin are desktop or web apps that connect to your database. But they require installation, local memory, and management. A browser-based SQL client eliminates setup friction: open your browser, enter your connection details, and start querying—no download, no configuration, no persistence on your machine.
MyDevTools SQL Client runs in your browser, encrypts your credentials with AES-256 before storing them, and keeps your connection details local. You can run SELECT, INSERT, UPDATE, DELETE, and administrative queries directly against PostgreSQL, MySQL, and MariaDB instances.
How to connect to your database
You need four pieces of information:
- Host — Domain or IP of the database server (e.g.,
db.example.comorlocalhost:5432). - Port — Default ports: PostgreSQL 5432, MySQL/MariaDB 3306.
- Username — Your database user.
- Password — Your user password.
Optionally provide a database name to start in a specific database context. Enter these details into the SQL Client, and it will attempt a connection. If successful, you can immediately start writing queries.
-- PostgreSQL connection example
Host: postgres.railway.app
Port: 5432
User: postgres
Password: ••••••••
-- MySQL connection example
Host: localhost
Port: 3306
User: root
Password: ••••••••Running queries and exploring schemas
Once connected, write any SQL query. The interface shows results in a table, with column headers, data types, and row counts. For larger result sets, pagination prevents the browser from loading millions of rows at once.
On the left sidebar, you can browse your database structure: list tables, columns, and their types. This schema explorer saves you from memorizing table names and column definitions.
-- List all tables
SELECT table_name FROM information_schema.tables
WHERE table_schema = 'public';
-- Count rows in a table
SELECT COUNT(*) FROM users;
-- Query with conditions
SELECT id, email, created_at FROM users
WHERE created_at > NOW() - INTERVAL '7 days'
ORDER BY created_at DESC;Exporting results and managing connections
Results can be exported to CSV for further analysis in spreadsheet tools. Multiple database connections can be saved securely—your credentials are encrypted with AES-256 in your browser storage before any sync, so the server never sees plaintext passwords.
Use the browser-based storage to quickly switch between development, staging, and production databases (with appropriate caution and role-based permissions on your database users).
Security: credentials and encrypted storage
Your database credentials are sensitive. MyDevTools SQL Client encrypts them with AES-256 in the browser before storing locally, so plaintext passwords never leave your machine. For production databases, follow your organization's credential policies: use temporary tokens, short-lived credentials, or SSH tunneling if available.
Frequently asked questions
Is it safe to paste my database password into an online SQL client?
Use a browser-based client that encrypts credentials locally before storage. MyDevTools SQL Client uses AES-256 encryption in your browser, so passwords never reach the server unencrypted. Avoid clients that send credentials over unencrypted connections.
Can I use SQL Client to manage production databases?
Yes, but follow your organization security policy. Use read-only credentials for production or temporary tokens with expiration. Never save production passwords in a shared tool.
Does SQL Client support PostgreSQL, MySQL, and MariaDB?
Yes, all three are supported. MariaDB is MySQL-compatible, so the same connection method works.
Can I run administrative commands like CREATE TABLE or DROP?
Yes, any SQL query that your user role permits. Make sure your user permissions match your intent (e.g., read-only for exploration, write access only for development).