PollySendGrid

Polly v8 resilience for SendGrid — add retry, timeout, and circuit-breaker to any email send in two lines.

var client = new SendGridClient(apiKey);

var resilient = client.WithPolly(pipeline => pipeline
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = SendGridTransientErrors.IsTransient,
    })
    .AddTimeout(TimeSpan.FromSeconds(30)));

var response = await resilient.SendEmailAsync(msg);

Why PollySendGrid?

SendGrid imposes rate limits and occasionally returns transient errors. Dropped emails mean missed notifications, failed password resets, and lost revenue. This library wraps the response check in Polly v8 so every transient error is retried automatically:

Problem	Solution
HTTP 429 rate limit exceeded	Auto-thrown as SendGridTransientException and retried
HTTP 500 transient server error	Auto-thrown as SendGridTransientException and retried
HTTP 503 service unavailable	Auto-thrown as SendGridTransientException and retried
HttpRequestException network failure	Caught by SendGridTransientErrors.IsTransient
Cascading failures during an outage	Wrap with AddCircuitBreaker

Installation

dotnet add package PollySendGrid
dotnet add package Polly.Core

Quick-start

1. Manual wiring

var client = new SendGridClient(apiKey);

var resilient = client.WithPolly(p => p
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = SendGridTransientErrors.IsTransient,
    }));

var msg = MailHelper.CreateSingleEmail(from, to, subject, plainText, htmlContent);
var response = await resilient.SendEmailAsync(msg);

2. Dependency injection

builder.Services.AddPollySendGrid(apiKey, pipeline => pipeline
    .AddRetry(new RetryStrategyOptions
    {
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true,
        ShouldHandle = SendGridTransientErrors.IsTransient,
    })
    .AddTimeout(TimeSpan.FromSeconds(30)));

public class EmailService(ResilientSendGridClient client)
{
    public Task<Response> SendAsync(SendGridMessage msg, CancellationToken ct)
        => client.SendEmailAsync(msg, ct);
}

Transient error reference

Condition	Why it's transient
SendGridTransientException (HTTP 429)	Rate limit — back off and retry
SendGridTransientException (HTTP 500)	Transient server error
SendGridTransientException (HTTP 503)	Service maintenance or overload
HttpRequestException	Network failure

Note: SendGridTransientException is thrown automatically by ResilientSendGridClient when the response status code is in SendGridTransientErrors.StatusCodes. You do not throw it yourself.

API reference

Member	Description
ResilientSendGridClient.Inner	The underlying ISendGridClient
SendEmailAsync(msg, ct)	Sends an email through the pipeline
ExecuteAsync<T>(operation, ct)	Runs any ISendGridClient operation through the pipeline
SendGridTransientErrors.IsTransient	PredicateBuilder for 429/500/503 + HttpRequestException
SendGridTransientErrors.StatusCodes	IReadOnlySet<HttpStatusCode> — TooManyRequests, InternalServerError, ServiceUnavailable
client.WithPolly(pipeline)	Wraps ISendGridClient with a pre-built pipeline
client.WithPolly(configure)	Builds pipeline inline and wraps the client
services.AddPollySendGrid(configure)	DI registration (requires ISendGridClient in DI)
services.AddPollySendGrid(apiKey, configure)	DI registration with API key shortcut

Target frameworks

.NET 6 ✅ · .NET 8 ✅ · .NET 9 ✅

Related packages

Package	Description
PollyAzureBlob	Polly v8 for Azure Blob Storage
PollyAzureServiceBus	Polly v8 for Azure Service Bus
PollyAzureKeyVault	Polly v8 for Azure Key Vault
PollyAzureEventHub	Polly v8 for Azure Event Hubs
PollyCosmosDb	Polly v8 for Azure Cosmos DB
PollyElasticsearch	Polly v8 for Elasticsearch
PollyRedis	Polly v8 for StackExchange.Redis
PollyEFCore	Polly v8 for Entity Framework Core
PollyDapper	Polly v8 for Dapper
PollyMongo	Polly v8 for MongoDB
PollyNpgsql	Polly v8 for Npgsql (PostgreSQL)
PollySqlClient	Polly v8 for Microsoft.Data.SqlClient
PollyGrpc	Polly v8 for gRPC
PollyRabbitMQ	Polly v8 for RabbitMQ
PollyKafka	Polly v8 for Confluent.Kafka
PollySignalR	Polly v8 for SignalR
PollyOpenAI	Polly v8 for OpenAI .NET SDK
PollyMediatR	Polly v8 for MediatR
PollyHealthChecks	Polly v8 for ASP.NET Core Health Checks
PollyMassTransit	Polly v8 for MassTransit
PollyAzureTableStorage	Polly v8 for Azure Table Storage
PollyMailKit	MailKit SMTP email client
PollyAzureQueueStorage	Azure Queue Storage QueueClient
PollyHangfire	Hangfire IBackgroundJobClient
PollyBackoff	Polly v8 backoff helpers

💼 Need .NET consulting?

The author of this package is available for consulting on Polly v8 resilience, Azure cloud architecture, and clean .NET design.

→ solidqualitysolutions.com · LinkedIn

License

MIT © Justin Bannister