Light on the hot path.
Struct outcomes, pooled contexts and ValueTask keep successful calls fast. State-passing overloads avoid closure allocations.
FAST RESILIENCE FOR .NETBuilt to
Built to
take a hit.
Dependencies fail. Your application doesn’t have to. Wrap every call in a little Kevlar.
Retries, circuit breakers, timeouts and more.
Seven strategies. One fluent shield API.
dotnet add package KevlarSTRONG PROTECTION. LIGHT FOOTPRINT.
NativeAOT readyAllocation-consciousOpen source
LAYERS OF RESILIENCEWhatever breaks.
Whatever breaks.
There’s a strategy for that.
Pick the protection your dependency needs. Chain strategies together into one reusable shield.
Retry
Give transient failures another chance.
Circuit breaker
Let struggling dependencies recover.
Timeout
Keep every call within its budget.
Rate limit
Set a sustainable pace for requests.
Concurrency limit
Keep concurrent work under control.
Hedging
Race another attempt against a slow call.
Fallback
Have an answer when a dependency fails.
Stronger together.
Compose your own protection.
LESS CEREMONY. MORE CONFIDENCE.Looks like code.
Looks like code.
Works like armor.
Build a shield once. Reuse it across calls. Protection reads in execution order, from the outside in.
- 01Set the budget
Timeout bounds the whole operation.
- 02Handle the unexpected
Retry adds backoff and jitter by default.
- 03Give failures a limit
The circuit breaker stops repeated failures.
YourFirstShield.csC#
using Kevlar;
var shield = Shield
.Timeout(TimeSpan.FromSeconds(30))
.Retry(3)
.CircuitBreaker(
consecutiveFailures: 5,
breakDuration: TimeSpan.FromSeconds(30));
var user = await shield.ExecuteAsync(
ct => LoadUserAsync(id, ct), cancellationToken);
STRENGTH WITHOUT THE WEIGHT01 / PERFORMANCE 02 / CONTROL 03 / COMPATIBILITY
Heavy on resilience. Light on everything else.
Your intent. Your rules.
Shield.When<TimeoutExceededException>().Retry(3) says what you mean. Start with sensible defaults; fine-tune with options.
Ready for your stack.
Targets netstandard2.0 and net10.0. NativeAOT-ready, with integrations for Microsoft DI and HttpClientFactory.
