Retrybackoff

Retrybackoff (often written as retry backoff or retry-with-backoff) is a fault-tolerance technique used in networked and distributed systems to manage repeated attempts after transient failures. It spaces out successive retry attempts according to a predetermined schedule or algorithm to reduce load, avoid congestion, and increase the probability of success as transient conditions resolve.

Common strategies include fixed backoff (constant delay between attempts), linear backoff (delay increases by a constant amount), and exponential backoff (delay grows multiplicatively, typically doubling). Jitter, a small random variation added to delays, is frequently combined with these strategies to prevent synchronized retry storms (the thundering herd problem). Practical implementations also enforce limits such as maximum delay, maximum number of attempts, and total retry timeout.

Effective use of retrybackoff requires classifying errors (distinguishing transient from permanent failures), ensuring idempotency of retried operations where possible, and balancing responsiveness with system stability. It is widely used for HTTP clients, RPC frameworks, message delivery, and database reconnections. Alternatives or complements include circuit breakers, rate limiters, and bulkheads, which provide different mechanisms to protect services under load.

When configuring retrybackoff, practitioners consider base delay, backoff factor, jitter strategy, maximum cap, and error-handling rules. Properly tuned backoff reduces unnecessary retries, lowers latency variability, and improves overall system resilience.