C# / .NET Esignature API Integration
The SignThem REST API integrates cleanly into any .NET application using the built-in HttpClient. The example below uses System.Text.Json and async/await patterns compatible with .NET 6 and later. A first-party NuGet package is planned - join the waitlist to be notified when it is available.
Installation
dotnet add package System.Net.Http.JsonCreate and send an envelope
The example below creates an envelope, adds a recipient with a signature field, and sends it. The recipient receives an email with a secure signing link.
using System.Net.Http.Headers;
using System.Net.Http.Json;
var apiKey = Environment.GetEnvironmentVariable("SIGNTHEM_API_KEY")!;
var baseUrl = "https://signthem.ai/api/v1";
using var http = new HttpClient();
http.DefaultRequestHeaders.Authorization =
new AuthenticationHeaderValue("Bearer", apiKey);
// 1. Create an envelope
var envelope = await http.PostAsJsonAsync($"{baseUrl}/envelopes", new {
name = "Service Agreement",
documents = new[] {
new { url = "https://yourapp.com/contracts/agreement.pdf" },
},
});
var envelopeData = await envelope.Content.ReadFromJsonAsync<JsonElement>();
var envelopeId = envelopeData.GetProperty("id").GetString();
// 2. Add a recipient with a signature field
await http.PostAsJsonAsync($"{baseUrl}/envelopes/{envelopeId}/recipients", new {
email = "[email protected]",
name = "Jane Smith",
fields = new[] {
new { type = "signature", page = 1, x = 100, y = 600 },
new { type = "date", page = 1, x = 320, y = 600 },
},
});
// 3. Send - recipient receives an email with a signing link
await http.PostAsync($"{baseUrl}/envelopes/{envelopeId}/send", null);
Console.WriteLine($"Envelope sent: {envelopeId}");Why C# / .NET developers choose SignThem
No third-party dependencies
uses built-in HttpClient and System.Text.Json
Fully async
compatible with ASP.NET Core, Azure Functions, and Worker Services
Strongly typed request/response models map naturally to C# records or classes
Official .NET NuGet package coming soon
join the waitlist for early access
Native SDK in development
A first-party SDK for this language is on the roadmap. In the meantime, the REST API works with any HTTP client as shown in the example above. Join the waitlist and we will notify you when the SDK ships.
Related resources
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