.NET Core Production Best Practices

Apply production-grade best practices for .NET Core applications — configuration management, resilience patterns, and operational excellence.

45 min•By Priygop Team•Last updated: Feb 2026

Configuration & Resilience

Configuration Hierarchy: appsettings.json → appsettings.{env}.json → environment variables → user secrets → Key Vault. Later sources override earlier ones
Options Pattern: Bind configuration sections to strongly-typed classes — IOptions<T> (singleton), IOptionsSnapshot<T> (scoped, reloads on change), IOptionsMonitor<T> (real-time updates)
Resilience (Polly): Retry with exponential backoff, circuit breaker, timeout, bulkhead isolation — Microsoft.Extensions.Http.Resilience integrates with HttpClientFactory
HttpClientFactory: Create and manage HttpClient instances — connection pooling, DNS rotation, Polly integration. Never new HttpClient() directly
Background Tasks: Use IHostedService for startup initialization, BackgroundService for continuous processing, IHostedLifecycleService for lifecycle hooks
Feature Flags: Use Microsoft.FeatureManagement — toggle features without deployment. Percentage rollout, time-window flags, targeting filters

Try It Yourself: API Builder

Try It Yourself: API BuilderHTML⚠ 14 errors

⚠ Syntax Issues (14)

Line 26: Unknown tag <list> on line 26

💡 "<list>" is not a valid HTML5 element. Use <div>, <span>, <p>, <section>, etc.

Line 29: Unknown tag <actionresult> on line 29

💡 "<actionresult>" is not a valid HTML5 element. Use <div>, <span>, <p>, <section>, etc.

Line 36: Unknown tag <actionresult> on line 36

💡 "<actionresult>" is not a valid HTML5 element. Use <div>, <span>, <p>, <section>, etc.

Line 43: Unknown tag <actionresult> on line 43

💡 "<actionresult>" is not a valid HTML5 element. Use <div>, <span>, <p>, <section>, etc.

Line 54: Wrong closing tag: </script> found, expected </actionresult> (line 54)

💡 Close <actionresult> (opened on line 43) with </actionresult> before closing </script>.

Line 54: Wrong closing tag: </body> found, expected </actionresult> (line 54)

💡 Close <actionresult> (opened on line 43) with </actionresult> before closing </body>.

Line 54: Wrong closing tag: </html> found, expected </actionresult> (line 54)

💡 Close <actionresult> (opened on line 43) with </actionresult> before closing </html>.

Line 2: Unclosed <html> (opened on line 2)

💡 Add </html> to properly close this element.

Line 9: Unclosed <body> (opened on line 9)

💡 Add </body> to properly close this element.

Line 16: Unclosed <script> (opened on line 16)

💡 Add </script> to properly close this element.

Line 26: Unclosed <list> (opened on line 26)

💡 Add </list> to properly close this element.

Line 29: Unclosed <actionresult> (opened on line 29)

💡 Add </actionresult> to properly close this element.

Line 36: Unclosed <actionresult> (opened on line 36)

💡 Add </actionresult> to properly close this element.

Line 43: Unclosed <actionresult> (opened on line 43)

💡 Add </actionresult> to properly close this element.

HTML Editor

✕ 14 errorsTab = 2 spaces

<!DOCTYPE html>
<html><head><style>
body{font-family:Arial,sans-serif;padding:20px;background:#0f172a;color:#e2e8f0}
h2{color:#22d3ee}.card{background:#1e293b;padding:20px;border-radius:10px;max-width:550px}
select,input{width:100%;padding:8px;background:#0f172a;border:2px solid #334155;border-radius:6px;color:#e2e8f0;box-sizing:border-box;margin:4px 0;font-size:14px}
label{font-weight:bold;display:block;margin-top:10px;font-size:14px;color:#94a3b8}
button{background:#22d3ee;color:#0f172a;border:none;padding:10px 20px;border-radius:6px;cursor:pointer;font-weight:bold;margin-top:12px}
pre{background:#0f172a;padding:12px;border-radius:8px;font-size:12px;border:1px solid #334155;margin-top:12px;overflow-x:auto;line-height:1.5}
</style></head><body>
<div class="card"><h2>ASP.NET Core API Builder</h2>
<label>Resource:</label><input id="res" value="Products" />
<label>Method:</label>
<select id="method"><option>GET</option><option>POST</option><option>PUT</option><option>DELETE</option></select>
<button onclick="gen()">Generate Controller</button>
<pre id="code"></pre></div>
<script>
function gen(){
var r=document.getElementById("res").value||"Items";
var m=document.getElementById("method").value;
var code="[ApiController]
[Route("api/[controller]")]
public class "+r+"Controller : ControllerBase
{
";
if(m==="GET")code+="    [HttpGet]
    public async Task<list r>> GetAll()
        => await _db."+r+".ToListAsync();";
else if(m==="POST")code+="    [HttpPost]
    public async Task<actionresult> Create("+r+" item)
    {
        _db."+r+".Add(item);
        await _db.SaveChangesAsync();
        return Ok(item);
    }";
else if(m==="PUT")code+="    [HttpPut("{id}")]
    public async Task<actionresult> Update(int id, "+r+" item)
    {
        _db.Entry(item).State = Modified;
        await _db.SaveChangesAsync();
        return NoContent();
    }";
else code+="    [HttpDelete("{id}")]
    public async Task<actionresult> Delete(int id)
    {
        var item = await _db."+r+".FindAsync(id);
        _db."+r+".Remove(item);
        await _db.SaveChangesAsync();
        return NoContent();
    }";
code+="
}";
document.getElementById("code").textContent=code;}
gen();
</script></body></html>

<!DOCTYPE html>
<html><head><style>
body{font-family:Arial,sans-serif;padding:20px;background:#0f172a;color:#e2e8f0}
h2{color:#22d3ee}.card{background:#1e293b;padding:20px;border-radius:10px;max-width:550px}
select,input{width:100%;padding:8px;background:#0f172a;border:2px solid #334155;border-radius:6px;color:#e2e8f0;box-sizing:border-box;margin:4px 0;font-size:14px}
label{font-weight:bold;display:block;margin-top:10px;font-size:14px;color:#94a3b8}
button{background:#22d3ee;color:#0f172a;border:none;padding:10px 20px;border-radius:6px;cursor:pointer;font-weight:bold;margin-top:12px}
pre{background:#0f172a;padding:12px;border-radius:8px;font-size:12px;border:1px solid #334155;margin-top:12px;overflow-x:auto;line-height:1.5}
</style></head><body>
<div class="card"><h2>ASP.NET Core API Builder</h2>
<label>Resource:</label><input id="res" value="Products" />
<label>Method:</label>
<select id="method"><option>GET</option><option>POST</option><option>PUT</option><option>DELETE</option></select>
<button onclick="gen()">Generate Controller</button>
<pre id="code"></pre></div>
<script>
function gen(){
var r=document.getElementById("res").value||"Items";
var m=document.getElementById("method").value;
var code="[ApiController]
[Route("api/[controller]")]
public class "+r+"Controller : ControllerBase
{
";
if(m==="GET")code+="    [HttpGet]
    public async Task<List<"+r+">> GetAll()
        => await _db."+r+".ToListAsync();";
else if(m==="POST")code+="    [HttpPost]
    public async Task<ActionResult> Create("+r+" item)
    {
        _db."+r+".Add(item);
        await _db.SaveChangesAsync();
        return Ok(item);
    }";
else if(m==="PUT")code+="    [HttpPut("{id}")]
    public async Task<ActionResult> Update(int id, "+r+" item)
    {
        _db.Entry(item).State = Modified;
        await _db.SaveChangesAsync();
        return NoContent();
    }";
else code+="    [HttpDelete("{id}")]
    public async Task<ActionResult> Delete(int id)
    {
        var item = await _db."+r+".FindAsync(id);
        _db."+r+".Remove(item);
        await _db.SaveChangesAsync();
        return NoContent();
    }";
code+="
}";
document.getElementById("code").textContent=code;}
gen();
</script></body></html>

Result

Click ▶ Run to see the result

Edit the code on the left, then click Run

HTML|54 lines|2215 chars|14 errors, 0 warnings

UTF-8

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