Retry & Circuit Breaker Simulator

Retry & Circuit Breaker

Flakiness 40%

Base delay 300 ms

Max delay 8.0 s

Jitter 30%

Trip threshold 4 fails

Cooldown 4.0 s

Call rate 0.8 / s

Sim speed 1.0×

Circuit trips

Success rate

–

In flight / waiting

0 / 0

Avg attempts

–

How it works

Each request that fails is retried after a delay that doubles with every attempt — exponential backoff — clamped to a maximum and randomised with jitter so a burst of clients doesn't retry in lockstep. Independently, a circuit breaker watches the recent failure streak: once it hits the trip threshold the circuit snaps open and every call is short-circuited instantly (no network attempt) for the cooldown period, protecting a struggling server from more load. After cooldown the circuit goes half-open and lets exactly one trial request through — success closes the circuit, failure reopens it.

delay(n) = min(maxDelay, base·2ⁿ) · (1 ± jitter)
open → (now-openedAt ≥ cooldown) → half-open
half-open → success → closed
half-open → fail    → open (reset cooldown)

Flakiness — probability any single network attempt fails.
Base / Max delay — the exponential backoff floor and ceiling.
Jitter — random spread applied to each computed delay.
Trip threshold — consecutive failures needed to open the circuit.
Cooldown — how long the circuit stays open before probing again.

Real-world relevance: this pair of patterns is standard in mobile API clients and backend service meshes — backoff+jitter avoids retry storms, and the circuit breaker stops a client from hammering a downed dependency while it recovers.

CLOSED

In flight Success Failed attempt Blocked (breaker open)