How to implement a Retry policy with exponential backoff using Polly in .NET 8?

When building microservices or communicating with external APIs, transient network faults can cause temporary request failures. Implementing a retry strategy with exponential backoff helps mitigate these issues without overwhelming the downstream service.

Using Polly v8 Resilience Pipeline

With Polly v8 and Microsoft.Extensions.Resilience, you can construct a resilient pipeline using the ResiliencePipelineBuilder class.

Code Example

var pipeline = new ResiliencePipelineBuilder()
    .AddRetry(new RetryStrategyOptions
    {
        ShouldHandle = new PredicateBuilder().Handle<HttpRequestException>(),
        MaxRetryAttempts = 3,
        Delay = TimeSpan.FromSeconds(2),
        BackoffType = DelayBackoffType.Exponential,
        UseJitter = true
    })
    .Build();

await pipeline.ExecuteAsync(async cancellationToken =>
{
    // Perform HTTP operation here
    await MakeNetworkRequestAsync(cancellationToken);
});

Key Considerations

• Jitter: Adding randomness prevents the thundering herd problem.
• Transient Errors: Only retry operations that are transient (e.g., HTTP 503 or network socket timeouts).