Describe URL-Based Authentication.
Securing particular URLs, files, or route patterns so that only authorized users may access them is known as URL-based authentication.

Examples:
/admin only for Admins
/reports/daily only for Managers
/api/* only for logged-in users

1. URL-Based Authentication in ASP.NET Core
1.1 Protect a Folder or Route Pattern
Example: protect all URLs starting with /admin.
app.UseEndpoints(endpoints =>
{
    endpoints.MapControllerRoute(
        name: "admin",
        pattern: "admin/{controller=Dashboard}/{action=Index}/{id?}")
        .RequireAuthorization("AdminOnly");
});

Authorization policy:
builder.Services.AddAuthorization(options =>
{
    options.AddPolicy("AdminOnly",
        policy => policy.RequireRole("Admin"));
});

1.2 Protect a Specific URL
app.MapGet("/reports/daily", () => "Daily Report")
   .RequireAuthorization("ManagerOnly");
Policy:

options.AddPolicy("ManagerOnly",
    policy => policy.RequireRole("Manager"));
});
1.3 Protect Controller Actions
[Authorize(Roles = "Admin")]
public IActionResult Settings()
{
    return View();
}

This protects the URL /settings.

1.4 Custom Middleware to Block URLs
app.Use(async (context, next) =>
{
    var path = context.Request.Path.Value;

    if (path.StartsWith("/secret") && !context.User.Identity.IsAuthenticated)
    {
        context.Response.Redirect("/account/login");
        return;
    }

    await next();
});

2. URL-Based Authentication in Classic ASP.NET MVC (Non-Core)
2.1 Protect a Folder Using web.config
<location path="Admin">
  <system.web>
    <authorization>
      <deny users="?" />
      <allow roles="Admin" />
    </authorization>
  </system.web>
</location>

2.2 Protect a Single Page
<location path="Reports/Monthly.aspx">
  <system.web>
    <authorization>
      <deny users="?" />
      <allow roles="Manager" />
    </authorization>
  </system.web>
</location>

2.3 Protect Controller URL
[Authorize(Roles = "Admin")]
public ActionResult Dashboard()
{
    return View();
}

3. Role-Based URL Control Example
[Authorize(Roles = "Admin, Manager")]
public IActionResult Index()
{
    return View();
}
Route level:

endpoints.MapControllerRoute(
    name: "report",
    pattern: "reports/{*any}")
    .RequireAuthorization("ManagerOnly");

4. URL-Based Authentication for Web APIs
[Authorize]
[Route("api/orders")]
public class OrdersController : ControllerBase
{
    [HttpGet("{id}")]
    public IActionResult Get(int id)
    {
        return Ok();
    }
}

Protect all order-related API URLs:
app.MapControllerRoute("api-protected", "api/orders/{*path}")
   .RequireAuthorization();

Conclusion
ASP.NET Core provides middleware, routing, and policies for URL-based protection. Classic ASP.NET MVC uses web.config and Authorize attributes.

Key Functional Requirements
Users can type comments.
Auto-suggestions appear when typing @ for users.
Auto-suggestions appear when typing # for tags.
Comments should highlight mentions and hashtags.
Backend must store extracted mentions and tags.
Display comments with clickable mentions and hashtags.
Should support comment editing and deletion.

High-Level Workflow
User types comment →
Detect @mention or #tag →
Show suggestion list →
User selects item →
Submit comment →
Backend processes comment →
Save comment, mentions, tags →
Return formatted comment →
Display in UI

Sequence Diagram
User → Angular UI: Type comment
Angular UI → SuggestionService: Detect @ or #
SuggestionService → API: Fetch matching users or tags
API → Angular: Return suggestions
User → Angular: Select mention/tag
User → Angular: Submit final comment
Angular → API: Send comment text
API → Parser: Extract @mentions and #tags
Parser → DB: Save comment, mentions, tags
DB → API: Confirm save
API → Angular: Return formatted comment
Angular → User: Show updated comment list

Frontend Implementation (Angular)
Detecting Mentions and Hashtags in Textbox
<textarea
[(ngModel)]="commentText"
(keyup)="onKeyUp($event)"
placeholder="Write a comment...">
</textarea>

<div *ngIf="showSuggestions">
<ul class="suggestions">
<li *ngFor="let item of suggestions"
    (click)="selectSuggestion(item)">
  {{ item.display }}
</li>
</ul>
</div>

TypeScript Logic
onKeyUp(event: KeyboardEvent) {
  const text = this.commentText;
  const cursorPos = (event.target as HTMLTextAreaElement).selectionStart;

  const charBeforeCursor = text[cursorPos - 1];

  if (charBeforeCursor === '@') {
    this.loadUserSuggestions();
  }

  if (charBeforeCursor === '#') {
    this.loadTagSuggestions();
  }
}

loadUserSuggestions() {
  this.api.getUsers().subscribe(res => {
    this.showSuggestions = true;
    this.suggestions = res.map(u => ({ display: u.displayName, type: 'user', id: u.userId }));
  });
}

loadTagSuggestions() {
  this.api.getTags().subscribe(res => {
    this.showSuggestions = true;
    this.suggestions = res.map(t => ({ display: t.tagName, type: 'tag', id: t.tagId }));
  });
}

selectSuggestion(item: any) {
  const prefix = item.type === 'user' ? '@' : '#';
  this.commentText += prefix + item.display + ' ';
  this.showSuggestions = false;
}

Submitting the Comment
submitComment() {
  this.api.postComment({ content: this.commentText }).subscribe(() => {
    this.commentText = '';
    this.loadComments();
  });
}

Backend Implementation (ASP.NET Core)
Extracting Mentions and Tags
var mentions = Regex.Matches(model.Content, @"@(\w+)");
var tags = Regex.Matches(model.Content, @"#(\w+)");

API Controller

[HttpPost("comments")]
public async Task<IActionResult> PostComment(CommentDto model)
{
var comment = new Comment
{
    UserId = model.UserId,
    Content = model.Content,
    CreatedOn = DateTime.UtcNow
};

_db.Comments.Add(comment);
await _db.SaveChangesAsync();

// Extract mentions
var mentions = Regex.Matches(model.Content, @"@(\w+)")
                     .Select(m => m.Groups[1].Value)
                     .ToList();

foreach (var m in mentions)
{
    var user = _db.Users.FirstOrDefault(u => u.DisplayName == m);
    if (user != null)
    {
        _db.CommentMentions.Add(new CommentMention
        {
            CommentId = comment.CommentId,
            MentionedUserId = user.UserId
        });
    }
}

// Extract hashtags
var tags = Regex.Matches(model.Content, @"#(\w+)")
                .Select(m => m.Groups[1].Value)
                .ToList();

foreach (var t in tags)
{
    var tag = _db.Tags.FirstOrDefault(x => x.TagName == t)
              ?? new Tag { TagName = t };

    _db.CommentTags.Add(new CommentTag
    {
        CommentId = comment.CommentId,
        TagId = tag.TagId
    });
}

await _db.SaveChangesAsync();

return Ok();
}

Displaying Mentions and Hashtags with Highlighting
Angular Pipe
transform(value: string): string {
  value = value.replace(/@(\w+)/g, `<span class="mention">@$1</span>`);
  value = value.replace(/#(\w+)/g, `<span class="hashtag">#$1</span>`);
  return value;
}

UI Styling
.mention { color: #0275d8; font-weight: bold; }
.hashtag { color: #5cb85c; font-weight: bold; }
.suggestions { list-style: none; margin: 0; padding: 0; background: #f5f5f5; }
.suggestions li { padding: 6px; cursor: pointer; }

Best Practices

• Use caching for user and tag suggestions to improve performance
• Avoid over-querying the database
• Rate-limit comment submission
• Support soft delete for comments
• Implement pagination for comment lists
• Add real-time support using SignalR if needed

Conclusion
A comment system with mentions and hashtags adds professional collaboration capabilities to any web application. By using Angular for real-time processing and ASP.NET Core for strong backend parsing, you can build a scalable and reusable module. The design shown here works for enterprise portals, task management systems, social feeds, project tracking tools, LMS platforms, and more.

Performance, developer productivity, and platform consistency all significantly improve with the advent of.NET 10. For enterprise-grade applications, startups, and large-scale systems that prioritize dependability, this Long-Term Support (LTS) edition offers three years of guaranteed stability and support. In order to maintain its position as the foundation of contemporary cloud-native and AI-driven development, Microsoft 10 places a strong emphasis on the developer experience, cross-platform enhancements, and contemporary performance optimizations.

What's New for Long-Term Support (LTS) in.NET 10?
.NET 10 offers LTS with longer updates and patches, continuing Microsoft's regular release cycle. Because of its stability, it is the ideal option for enterprises planning multi-year installations or cloud-based services that require predictable upgrade pathways.

Improvements to the Runtime and Compiler
The JIT compiler and Common Language Runtime (CLR) have undergone significant performance and efficiency improvements.
Better method call inlining and de-virtualization, which lowers overhead.
More intelligent waste collection with fewer interruptions during demanding tasks.
Better code generation for value types and structs.
Memory optimizations for async methods and array interfaces.
Improved use of CPU-specific instructions for ARM64 and x64 platforms.

Developers will see measurable gains in throughput and latency-sensitive applications, especially APIs, microservices, and financial systems.

SDK and Tooling Upgrades
The .NET 10 SDK introduces smoother workflows and productivity improvements:

• File-based app support lets developers write and run C# scripts without full project scaffolding.
• Enhanced command-line tooling with more intelligent tab completion.
• Simplified global tools management using dotnet tool exec.
• Faster build and publish times through optimized MSBuild.
• Extended hot reload capabilities that apply even to project file edits.

These changes allow developers to focus on writing code rather than managing configurations.

File-Based Apps and Scripting
.NET 10 makes lightweight, single-file applications a reality. Developers can run .cs files directly with dotnet run using #sdk or #package directives at the top of the file. This streamlines scripting, prototyping, and building small utilities without creating full projects.

Example
#r "nuget: Newtonsoft.Json"using Newtonsoft.Json;
Console.WriteLine(JsonConvert.SerializeObject(new { Hello = "World" }));

Perfect for DevOps scripts, educational demos, or automation utilities, this feature makes .NET feel as lightweight as Python for small tasks.

ASP.NET Core 10 Innovations
ASP.NET Core receives key upgrades aimed at speed, security, and simplicity:

• Built-in support for OpenAPI 3.1 with full JSON Schema 2020-12 compatibility.
• Smarter middleware pipeline for minimal APIs with reduced startup time.
• Blazor enhancements including offline preloading, better reconnection UI, and unified resource handling.
• Identity now supports passkeys via FIDO2 and WebAuthn for passwordless authentication.
• Streamlined integration with Azure Container Apps and Kubernetes for scalable deployment.

Base Class Library Improvements
The Base Class Library (BCL) has been modernized across multiple areas:

• Span and Memory APIs have broader support across collections.
• JSON serialization performance is faster and more memory-efficient.
• File I/O now benefits from OS-level async optimizations.
• Networking libraries include QUIC enhancements and better HTTP/3 support.
• System.Security adds new cryptographic primitives and improved token handling.

These upgrades reinforce .NET’s position as one of the most efficient runtimes for high-performance and cloud-native workloads.

C# 14 Language Integration
.NET 10 ships with C# 14, introducing:

• The field keyword for backing field access in auto-properties.
• Extension blocks that group extension methods and properties logically.
• Null-conditional assignment operators (?.=).
• Implicit conversions for spans.
• Partial constructors and events for source generator support.

This tight integration between the runtime and language gives developers more expressive, concise, and performant code.

Cross-Platform and Cloud Improvements

• Improved support for macOS (Apple Silicon), Linux distributions, and containers.
• Reduced image sizes for container deployments.
• Better integration with GitHub Actions, Azure DevOps, and CI/CD pipelines.
• Performance optimization in WebAssembly (WASM) for Blazor apps.

.NET 10 continues to lead in portability, making it ideal for multi-environment applications.

Feature Comparison Table

Migration and Adoption Tips

• Update your global.json or project file to use <TargetFramework>net10.0</TargetFramework>.
• Run full regression tests, especially if you rely on unsafe or reflection-heavy code.
• Test ASP.NET Core projects for middleware or startup differences.
• For libraries, enable multi-targeting to support .NET 8 and .NET 10 simultaneously.
• Take advantage of the new hot reload and file-based tools to simplify CI/CD scripts.

Summary and Best Use Cases
.NET 10 marks a balanced evolution—focused on speed, simplicity, and modernization. It strengthens .NET’s cross-platform consistency, reinforces its position as a top-tier enterprise runtime, and makes day-to-day development faster and more enjoyable.

Best suited for:

• Enterprises needing long-term support and predictable upgrades
• Cloud-native applications and microservices
• Developers building modern APIs, AI, or high-performance systems
• Teams using DevOps automation and single-file tools
• Framework and library authors adopting C# 14 innovations

If you’re planning your next upgrade or building a new solution, .NET 10 is the best foundation for the next decade of development, fast, stable, and future-ready.

1. Overview — what this article covers
You will learn, step-by-step, how to implement DocuSign eSignature in a .NET (ASP.NET Core) app:

• key concepts and authentication options (JWT vs Authorization Code)
• installing and configuring the official DocuSign C# SDK and quickstart links.
• code sample to create and send an envelope (server-side)
• embedded signing (recipient view) sample for in-app signing
• implementing and securing DocuSign Connect (webhook) listener in ASP.NET Core, including validation.
• testing, error handling, logging, and deployment considerations
• best practices for security, compliance, and monitoring

I’ll include working C# snippets and notes you can drop into an ASP.NET Core project.

2. Quick background: DocuSign building blocks

• Account / Integration Key — your DocuSign developer account (Demo) and the App (Integration Key) you create in the DocuSign Admin.
• Envelope — a container for documents, recipients, and signing fields.
• Recipient & Tabs — signer (email/name) and signing tab positions (fields).
• Authentication — DocuSign supports OAuth: Authorization Code and JWT Grant; for server-to-server automated flows, JWT Grant is recommended.
• Connect (Webhooks) — DocuSign’s webhook system to notify your app of envelope events (completed, declined, etc.).

3. Prerequisites

1. DocuSign developer account ( https://developers.docusign.com ) — use Demo (sandbox).
2. Integration Key (app) created in DocuSign Admin with the redirect URI (if using Auth Code) or configured for JWT.
3. RSA keypair (private key) generated and uploaded to your DocuSign app (for JWT flow).
4. .NET 6 / .NET 7+ SDK and an ASP.NET Core Web API or MVC project.
5. NuGet packages: DocuSign.eSign (official C# SDK).

Install the SDK
dotnet add package DocuSign.eSign

4. Authentication: choose the right flow
JWT Grant (service integrations): no user interaction; server exchanges signed JWT for access token. Best for backend services that act on behalf of users or a system account. Requires consent once (admin or user).

Authorization Code Grant (user interactive): redirect user to DocuSign login page, user consents and returns code. Best for user-driven flows where the signer must authenticate with DocuSign.

Recommendation: Use JWT for server flows (creating envelopes programmatically, embedded signing server prepares envelope); use Authorization Code when the user must sign in to DocuSign itself.

5. Getting an access token (JWT) — minimal example

• Upload your RSA private key to the DocuSign app (Admin → Apps and Keys).
• Grant consent to your Integration Key for the impersonated user (admin consent or via browser link).

Below is a minimal JWT token flow using the DocuSign SDK helper. The SDK exposes helper classes; you can also form JWT by hand.
using DocuSign.eSign.Client;
using System.Security.Cryptography;
using System.IO;

public class DocuSignAuthService
{
    private readonly string _integrationKey = "<INTEGRATION_KEY>";
    private readonly string _userId = "<IMPERSONATED_USER_ID_GUID>";
    private readonly string _authBasePath = "account-d.docusign.com"; // demo
    private readonly string _privateKeyPath = "docusign_private_key.pem"; // RSA private key (PKCS8)

    public ApiClient CreateApiClient()
    {
        var apiClient = new ApiClient($"https://{_authBasePath}");
        return apiClient;
    }

    public string GetAccessToken()
    {
        var apiClient = CreateApiClient();
        // Read private key
        var privateKey = File.ReadAllText(_privateKeyPath);
        // Requests JWT token. SDK provides a helper method.
        var oauthToken = apiClient.RequestJWTUserToken(
            _integrationKey,
            _userId,
            new List<string> { "signature", "impersonation" },
            System.Text.Encoding.UTF8.GetBytes(privateKey),
            3600);
        return oauthToken.access_token;
    }
}

Notes

• Use the SDK method RequestJWTUserToken carefully (it expects private key bytes in a certain format). Refer SDK docs for exact signature.
• In production, store private keys in a secure store (KeyVault, AWS KMS) — never commit to repo.

6. Create and send an envelope (server side)
This example creates an envelope with a single PDF and a single signer.
using DocuSign.eSign.Api;
using DocuSign.eSign.Model;
using DocuSign.eSign.Client;
using System.Collections.Generic;

public class DocuSignService
{
    private readonly string _accountId;
    private readonly ApiClient _apiClient;

    public DocuSignService(string accessToken, string accountId, string basePath = "https://demo.docusign.net/restapi")
    {
        _apiClient = new ApiClient(basePath);
        _apiClient.Configuration.DefaultHeader.Add("Authorization", "Bearer " + accessToken);
        _accountId = accountId;
    }

    public EnvelopeSummary SendEnvelope(byte[] pdfBytes, string signerEmail, string signerName, string signerClientUserId = null)
    {
        var envelopesApi = new EnvelopesApi(_apiClient.Configuration);

        // Document
        var doc = new Document
        {
            DocumentBase64 = Convert.ToBase64String(pdfBytes),
            Name = "Sample Document",
            FileExtension = "pdf",
            DocumentId = "1"
        };

        // Signer
        var signer = new Signer
        {
            Email = signerEmail,
            Name = signerName,
            RecipientId = "1",
            RoutingOrder = "1"
        };

        // Example: add a signHere tab at absolute position
        signer.Tabs = new Tabs
        {
            SignHereTabs = new List<SignHere> {
                new SignHere { DocumentId = "1", PageNumber = "1", XPosition = "100", YPosition = "150" }
            }
        };

        var envDef = new EnvelopeDefinition
        {
            EmailSubject = "Please sign this document",
            Documents = new List<Document> { doc },
            Recipients = new Recipients { Signers = new List<Signer> { signer } },
            Status = "sent" // "sent" to send immediately, "created" to save as draft
        };

        var result = envelopesApi.CreateEnvelope(_accountId, envDef);
        return result;
    }
}

This SendEnvelope returns an EnvelopeSummary with the envelopeId you can store and track.

7. Embedded Signing (In-app signing / Recipient View)
For in-app signing (so the signer stays in your app), create a recipient view (signing URL). This requires the signer to be a embedded recipient — set clientUserId on the signer object.
public string CreateRecipientView(string envelopeId, string signerEmail, string signerName, string returnUrl)
{
    var viewRequest = new RecipientViewRequest
    {
        ReturnUrl = returnUrl, // user returns here after signing
        ClientUserId = "123",  // must match Signer.clientUserId
        AuthenticationMethod = "none",
        UserName = signerName,
        Email = signerEmail
    };

    var envelopesApi = new EnvelopesApi(_apiClient.Configuration);
    var result = envelopesApi.CreateRecipientView(_accountId, envelopeId, viewRequest);
    return result.Url; // redirect user to this URL (or open in iframe if allowed)
}

Notes and security
Use clientUserId to mark recipient as embedded.

For security, generate and validate any tokens you use to let only authenticated users open the signing session.

DocuSign recommends opening the signing URL in a browser window (or iframe with proper CSP and headers) — test cross-origin policies.

8. DocuSign Connect (Webhook) — implement listener in ASP.NET Core
DocuSign Connect delivers envelope events to your public webhook endpoint. Implement a listener to receive JSON/XML notifications and verify them.

Simple controller endpoint
[ApiController]
[Route("api/docusign")]
public class DocuSignController : ControllerBase
{
    [HttpPost("connect")]
    public async Task<IActionResult> Connect()
    {
        // DocuSign may send XML or JSON based on configuration
        string body;
        using (var reader = new StreamReader(Request.Body))
        {
            body = await reader.ReadToEndAsync();
        }

        // Optionally log the raw payload (ensure PII rules)
        // Validate using HMAC or OAuth method (recommended)
        // Process payload: parse envelope status, recipient events etc.

        // Respond with 200 OK quickly
        return Ok();
    }
}

Validation options (recommended):
HMAC-SHA256 validation: DocuSign can be configured to sign the payload and you validate using your shared secret.
OAuth (Connect validation) : DocuSign provides an OAuth method where they send a JWT/assertion you can validate. See DocuSign docs for recommended validation.

Example: validating HMAC
public bool ValidateHmac(string requestBody, string hmacHeader, string secret)
{
    var keyBytes = Encoding.UTF8.GetBytes(secret);
    using var hmac = new HMACSHA256(keyBytes);
    var computed = hmac.ComputeHash(Encoding.UTF8.GetBytes(requestBody));
    var computedBase64 = Convert.ToBase64String(computed);
    return string.Equals(computedBase64, hmacHeader, StringComparison.InvariantCulture);
}

Configure DocuSign Admin for Connect to include your HMAC key, and check the header (DocuSign sends it in X-DocuSign-Signature or similar; check current header name in the docs).

9. Processing webhook events — idempotency & state transitions

• Idempotency : Webhooks may be retried — make processing idempotent by tracking eventId or envelopeId+eventTimestamp.
• Event types : sent , delivered , completed , declined , voided — handle only the ones you care about.
• Security : Validate sender before processing (HMAC/OAuth).
• Queue background work : Return 200 OK quickly; enqueue heavy work (DB updates, notifications) to background processors (Hangfire, Azure Functions, background queue).

10. Local testing with DocuSign Demo & ngrok

• Use the DocuSign Demo account ( account-d.docusign.com ) for development.
• For webhook testing, use ngrok to expose your local endpoint and register it in DocuSign Connect settings or in your app’s Connect config.

Example with ngrok
ngrok http 5000
# Use the generated https URL in DocuSign Connect settings

Set the Connect listener to POST to https://<your-ngrok-id>.ngrok.io/api/docusign/connect .

11. Error handling, retries, and monitoring

• Retry logic : DocuSign retries webhooks on non-2xx responses. Make sure your endpoint responds 200 quickly for accepted payloads.
• Logging : Log envelopeId, event, timestamp, signer info (avoid logging sensitive fields). Use structured logging (Serilog) and centralize logs (ELK, Seq).
• Metrics : Monitor envelope creation rates, webhook failures, token expiry errors.
• Alerts : Alert on repeated webhook delivery failures or auth token rejection rates.

12. Example: End-to-end flow (step diagram)
Developer / System
   └─> Create Envelope (server) --> DocuSign eSignature API (Create Envelope)
         └─> DocuSign sends email to recipient (if remote) OR
         └─> Server requests Recipient View URL (embedded signing) and returns URL to client

User (if embedded) visits signing URL -> signs -> DocuSign updates envelope status

DocuSign Connect (webhook) --> Your webhook endpoint (/api/docusign/connect)
   └─> You validate (HMAC / OAuth) --> enqueue processing (update DB, send notifications)

13. Deployment & CI/CD tips

• Keep your DocuSign environment variables (Integration Key, AccountId, UserId, Private Key reference, base URL) in secure pipeline secrets (GitHub Actions secrets, Azure Key Vault).
• If you use JWT, ensure the private key is stored in Key Vault and injected into the build/runtime securely.
• Automate tests using DocuSign Demo environment (create test envelopes and assert status transitions).
• Post-deploy step: validate integration by creating a test envelope and checking the Connect webhook roundtrip.

14. Security & compliance recommendations

• Use HTTPS for all endpoints.
• Store private keys securely (Azure KeyVault, AWS KMS).
• Use JWT with short lifetimes and refresh tokens only as needed.
• Mask or avoid storing PII in logs; use tokenization for sensitive values.
• Audit trails : record which app/user created/modified envelopes (DocuSign records audit data; also replicate key events to your logs for compliance).
• Consent and legal : ensure proper consent for e-signature use in your jurisdiction; DocuSign provides guidance for legal enforceability.

15. Testing & QA checklist

• Create envelopes with different document types (PDF, DOCX) and verify field placement.
• Test embedded signing flows across browsers and mobile.
• Test webhook delivery and validation (use invalid signature to confirm rejection).
• Simulate retries by forcing 5xx from your endpoint to ensure idempotent handling.
• Validate token refresh and error handling when access token expires.

16. Useful DocuSign resources (official)

• DocuSign eSignature C# SDK docs and setup.
• How to get an access token with JWT Grant (official guide).
• DocuSign Connect (webhooks) implementation details and security.
• Official GitHub C# client repo & code examples.
• (These five references are the most load-bearing sources for setup, auth, SDK, and webhook guidance.)

17. Common pitfalls and how to avoid them

• Private key format mismatch : SDK expects PKCS8/PEM in certain formats — use the SDK examples or convert keys with openssl .
• Missing user consent for JWT : you must obtain consent for the impersonation user once. Use the consent URL provided by DocuSign or have an admin grant consent.
• Webhook not reachable (ngrok vs production) : use stable endpoints in production and avoid relying on tunneling for long-term operation.
• Incorrect envelope status handling : treat "completed" as verified final state; be careful with "delivered" vs "completed".
• Testing in production : don’t mix demo and production credentials.

18. Advanced topics (next steps)

• Templates : Create reusable templates in DocuSign and create envelopes from templates to simplify repeated documents.
• Bulk sending : Use bulk send for high-volume signature workflows.
• PowerForms : Use PowerForms for self-service signature forms.
• Hybrid approach : Use Authorization Code for user-initiated flows and JWT for system automation.
• Connect & storage : Replace heavy webhook processing with serverless functions if you want autoscaling and pay-per-use.

19. Example repository & samples
DocuSign maintains sample repos and quickstarts (C# examples) to help you start quickly — the official GitHub repo and Developer Center have ready examples you can clone and run.

20. Summary — practical checklist before go-live

• Developer account with Integration Key and correct redirect/consent configured.
• Private key stored securely and not in source control.
• Access tokens and refresh strategy implemented (JWT for server).
• Envelope creation + recipient view flows working end-to-end.
• Webhook listener implemented, validated (HMAC/OAuth), and idempotent.
• Logging, monitoring, and alerts in place for failures and retries.
• QA: cross-browser signing, mobile signing, retry behavior tested.
• Legal/compliance: retention, consent, and audit trail verified.

Microsoft Blazor has emerged as one of the most fascinating technologies in the field of contemporary web development. Blazor makes it simpler for.NET developers to use the same language for front-end and back-end development by enabling them to create interactive web user interfaces (UIs) using C# rather than JavaScript.

Blazor has developed into a unified web user interface framework that supports server-side, client-side, and static rendering under one roof with ASP.NET Core 9 (2025).

Blazor: What is it?
Blazor is an ASP.NET Core-based web user interface framework.
It renders HTML using Razor components (.razor files), and you can handle logic directly in C#.

Earlier, Blazor came in two major forms:

Now, in 2025, Microsoft has merged these concepts into a unified Blazor model.

Evolution of Blazor (Timeline)

Blazor 2018 → Blazor Server 2019 → Blazor WebAssembly 2020
      ↓
Blazor Hybrid (MAUI) 2022 → Blazor United 2023 → Blazor in ASP.NET Core 9 (2025)

Each version improved performance, interactivity, and tooling.
Blazor 2025 brings them all together into a single powerful framework.

Unified Rendering Model in ASP.NET Core 9

In ASP.NET Core 9, Blazor offers three rendering modes within the same app:

You can mix and match these modes per component.

Flowchart: Unified Blazor Rendering

┌────────────────────┐
          │    Blazor Page     │
          └──────┬─────────────┘
                 │
       ┌─────────┴─────────┐
       │                   │
┌─────────────┐     ┌──────────────┐
│ Server Mode │     │ WebAssembly  │
└─────────────┘     └──────────────┘
       │                   │
       ▼                   ▼
 SignalR Updates       Browser Execution
       │                   │
       └─────────► Unified Blazor UI ◄─────────┘

This makes Blazor extremely flexible for any type of web app — from dashboards to public portals.

Visual Representation (UI Diagram)

+-------------------------------------------------------+
| ASP.NET Core 9 App                                   |
|-------------------------------------------------------|
|  Controllers | APIs | Razor Components | Middleware   |
|-------------------------------------------------------|
|  Shared C# Models and Services                       |
|-------------------------------------------------------|
|  Blazor Rendering Modes                              |
|   → Static | Interactive Server | WASM               |
+-------------------------------------------------------+

This structure lets developers use one shared C# codebase for everything.

Example: Hybrid Rendering in a Blazor Component

@page "/dashboard"
@rendermode InteractiveServer
<h3>Dashboard</h3>

<p>Welcome @userName!</p>

<button @onclick="LoadData">Load Data</button>

@if (data != null)
{
    <ul>
        @foreach (var item in data)
        {
            <li>@item</li>
        }
    </ul>
}

@code {
    private string userName = "Rajesh";
    private List<string>? data;

    private void LoadData()
    {
        data = new List<string> { "Order 1", "Order 2", "Order 3" };
    }
}

This example uses Interactive Server Mode — meaning data binding and events are managed from the server in real time.

Performance Improvements in 2025

• Streaming Rendering: HTML starts rendering even before backend finishes.
• Auto Prerendering: Faster initial load with deferred interactivity.
• Smaller WASM Payload: Reduced download size for Blazor WebAssembly apps.
• Enhanced Hot Reload: Changes apply instantly during development.
• Server + Client Sync: Same Razor components can render on both ends.

Integration with .NET MAUI and Hybrid Apps
Blazor 2025 fully integrates with .NET MAUI — so developers can build:

• Web apps
• Desktop apps (Windows, Mac)
• Mobile apps (Android, iOS)

all using the same Blazor components.

Blazor + Security Enhancements
ASP.NET Core 9 improves security integration:

• Built-in authentication/authorization with OpenID Connect
• Better CSRF protection
• Improved Identity scaffolding
• SignalR security for real-time Blazor Server apps

Why Blazor is the Future of .NET Web Development

Flow Summary Diagram

Frontend (UI)  →  Blazor Components (.razor)
       ↓
Backend (Logic) → ASP.NET Core Controllers / APIs
       ↓
Database (Data) → SQL Server / EF Core
       ↓
Output          → Responsive Interactive Web App

Conclusion

Blazor in ASP.NET Core 9 (2025) represents the next stage of .NET Web UI evolution. It unifies server, client, and hybrid rendering, offers high performance, and reduces complexity for developers. If you’re a .NET or C# developer, learning Blazor in 2025 is one of the smartest moves to stay future-ready. Pro Tip: Combine Blazor with SignalR, EF Core, and Azure to build modern, full-stack, real-time applications all powered by .NET 9.