coder000

Connection string checker

Paste a .NET connection string — PostgreSQL (Npgsql), SQL Server, MySQL or SQLite — and get it back in the provider's canonical spelling with every key explained in plain English, plus honest warnings for the things that bite in production: a password sitting inline, TLS switched off or trusting any certificate, timeouts and pooling left to chance.

Your string is checked on the server and forgotten. Nothing is stored, nothing is logged, no connection is ever opened — the checker only reads the text. The password is masked as ***** in the result and never appears in any note or warning. Prefer not to paste a real one? Swap the password for anything: the advice is the same.

Free API — use it from your own tools

The same engine powers an open API (this page uses it too). No signup, no key — just a rate limit of 60 requests per minute per IP. Handy for a pre-commit hook, a CI check on appsettings files, or a code-review bot. The API masks the password exactly like the page does, and stores nothing.

curl

curl -X POST https://www.coder000.com/api/v1/connection-string \
  -H "Content-Type: application/json" \
  -d '{"input": "Host=db;Database=shop;Username=app;Password=x;SSL Mode=Disable"}'

C#

using var http = new HttpClient();
var response = await http.PostAsJsonAsync(
    "https://www.coder000.com/api/v1/connection-string",
    new { input = "Server=.;Database=Shop;Integrated Security=true;TrustServerCertificate=true" });
var result = await response.Content.ReadFromJsonAsync<JsonElement>();
Console.WriteLine(result.GetProperty("output").GetString());
foreach (var w in result.GetProperty("warnings").EnumerateArray())
    Console.WriteLine(w.GetProperty("change").GetString());

Uniform response shape: { "output": "…", "notes": [...], "warnings": [...] } — each note carries a change, an explanation, and a link to the tutorial behind the advice where one exists.

What it checks, and what it doesn't

Provider detection is a guess from the keys you use — Host and Username point at Npgsql, Data Source and Initial Catalog at SqlClient, Port 3306 at MySQL, a .db path at SQLite. A string that only uses the shared keys (Server, Database, User ID, Password) is checked generically and told so. The checker reads the text; it never opens a connection, so it cannot tell you whether the server exists, the password is right, or the certificate is valid — only whether the settings are the ones you would want in production.

Secure coding basics: keep secrets out of code Deploying to a VPS: secrets stay on the server PostgreSQL with .NET and EF Core Scaffolding: the SQLite → PostgreSQL swap Sibling tool: T-SQL → PostgreSQL Sibling tool: schema reviewer