diff --git a/source/errors.ts b/source/errors.ts
new file mode 100644
index 0000000..02b32f7
--- /dev/null
+++ b/source/errors.ts
@@ -0,0 +1,22 @@
+/**
+ * Error thrown when the maximum number of retries is hit in an exponential backoff
+ */
+export class ExponentialBackoffMaxRetriesHitError extends Error {
+    constructor(errors: Array<Error>) {
+        super('Exponential backoff: Max retries hit', { cause: errors });
+        this.name = 'ExponentialBackoffMaxRetriesHitError';
+    }
+}
+
+/**
+ * Error thrown when the exponential backoff retries are stopped
+ */
+export class ExponentialBackoffStoppedRetriesError extends Error {
+    constructor(reason: unknown) {
+        // Convert the reason to an error if it is not an error
+        const reasonError = reason instanceof Error ? reason : new Error(`${reason}`);
+
+        super(`Exponential backoff was aborted: "${reasonError.message}"`, { cause: reasonError });
+        this.name = 'ExponentialBackoffStoppedRetriesError';
+    }
+}
diff --git a/source/exponential-backoff.ts b/source/exponential-backoff.ts
new file mode 100644
index 0000000..8b7b8a8
--- /dev/null
+++ b/source/exponential-backoff.ts
@@ -0,0 +1,275 @@
+import { ExponentialBackoffStoppedRetriesError, ExponentialBackoffMaxRetriesHitError } from './errors.ts';
+
+/**
+ * Exponential backoff is a technique used to retry a function after a delay.
+ *
+ * The delay increases exponentially with each attempt, up to a maximum delay.
+ *
+ * The jitter is a random amount of time subtracted from the delay to prevent thundering herd problems.
+ *
+ * The growth rate is the factor by which the delay increases with each attempt.
+ */
+export class ExponentialBackoff {
+    readonly #options: ExponentialBackoffOptions;
+
+    /**
+     * Creates a new exponential-backoff instance.
+     *
+     * Unspecified options use the defaults listed below.
+     *
+     * @param options - Exponential-backoff configuration overrides.
+     * @param options.maxDelay - Maximum delay between retries. Default: `10_000` ms.
+     * @param options.maxAttempts - Maximum number of attempts; `0` retries indefinitely. Default: `10`.
+     * @param options.baseDelay - Delay used as the basis for the first retry. Default: `1_000` ms.
+     * @param options.growthRate - Multiplier applied to the delay after each attempt. Default: `2`.
+     * @param options.jitter - Maximum proportional reduction subtracted from each delay (0–1). Default: `0.1`.
+     */
+    constructor(options: Partial<ExponentialBackoffOptions> = {}) {
+        this.#options = {
+            maxDelay: 10_000,
+            maxAttempts: 10,
+            baseDelay: 1_000,
+            growthRate: 2,
+            jitter: 0.1,
+            ...options,
+        };
+
+        ExponentialBackoff.validateOptions(this.#options);
+    }
+
+    /**
+     * Create a new ExponentialBackoff instance
+     *
+     * @param config - The configuration for the exponential backoff
+     * @returns The ExponentialBackoff instance
+     */
+    static from(config?: Partial<ExponentialBackoffOptions>): ExponentialBackoff {
+        const backoff = new ExponentialBackoff(config);
+
+        return backoff;
+    }
+
+    /**
+     * Run the function with exponential backoff
+     *
+     * @param taskFn - The function to run
+     * @param onError - The callback to call when an error occurs
+     * @param options - The configuration for the exponential backoff
+     *
+     * @throws An {@link ExponentialBackoffMaxRetriesHitError} with all the errors that were thrown by the task function
+     * @throws An {@link ExponentialBackoffStoppedRetriesError} if the abort signal is activated
+     *
+     * @returns The result of the function
+     */
+    static run<T>(
+        taskFn: (callbackParameters: ExponentialBackoffCallbackParameters) => Promise<T>,
+        onError = (_error: Error): void => {},
+        options?: Partial<ExponentialBackoffOptions>,
+    ): Promise<T> {
+        const backoff = ExponentialBackoff.from(options);
+
+        return backoff.run(taskFn, onError);
+    }
+
+    /**
+     * Calculate the delay before we should attempt to retry
+     *
+     * @param options - The configuration for the exponential backoff
+     * @param attempt - The current attempt number
+     * @returns The time in milliseconds before another attempt should be made
+     */
+    public static calculateDelay(options: ExponentialBackoffOptions, attempt: number): number {
+        // Get the power of the growth rate
+        const power = options.growthRate ** attempt;
+
+        // Get the delay before jitter or limit
+        const rawDelay = options.baseDelay * power;
+
+        // Cap the delay to the maximum. Do this before the jitter so jitter does not become larger than delay
+        const cappedDelay = Math.min(rawDelay, options.maxDelay);
+
+        // Get a random number for the amount to "jitter" the delay by
+        const jitterAmount = Math.random();
+
+        // Calculate the jitter
+        const jitter = jitterAmount * options.jitter * cappedDelay;
+
+        // Subtract the jitter from the delay
+        return cappedDelay - jitter;
+    }
+
+    /**
+     * Validate the options for the exponential backoff
+     *
+     * @param options - The options to validate
+     *
+     * @throws An error if the options are invalid
+     */
+    public static validateOptions(options: ExponentialBackoffOptions): void {
+        // Validate the max delay is a finite number not less than 0
+        if (!Number.isFinite(options.maxDelay)) {
+            throw new Error('maxDelay must be a finite number');
+        }
+
+        if (options.maxDelay < 0) {
+            throw new Error('maxDelay must be not less than 0');
+        }
+
+        // Validate the max attempts is a finite number not less than 0
+        if (!Number.isFinite(options.maxAttempts)) {
+            throw new Error('maxAttempts must be a finite number');
+        }
+
+        if (options.maxAttempts < 0) {
+            throw new Error('maxAttempts must be not less than 0');
+        }
+
+        // Validate the base delay is a finite number not less than 0
+        if (!Number.isFinite(options.baseDelay)) {
+            throw new Error('baseDelay must be a finite number');
+        }
+
+        if (options.baseDelay < 0) {
+            throw new Error('baseDelay must be not less than 0');
+        }
+
+        // Validate the growth rate is a finite number not less than 0
+        if (!Number.isFinite(options.growthRate)) {
+            throw new Error('growthRate must be a finite number');
+        }
+
+        if (options.growthRate < 0) {
+            throw new Error('growthRate must be not less than 0');
+        }
+
+        // Validate the jitter is a finite number not less than 0 or greater than 1
+        if (!Number.isFinite(options.jitter)) {
+            throw new Error('jitter must be a finite number');
+        }
+
+        if (options.jitter < 0 || options.jitter > 1) {
+            throw new Error('jitter must be not less than 0 or greater than 1');
+        }
+    }
+
+    /**
+     * Run the function with exponential backoff
+     *
+     * If the function fails but we have not hit the max attempts, the error will be passed to the onError callback
+     * and the function will be retried with an exponential delay
+     *
+     * If the function fails and we have hit the max attempts, an ExponentialBackoffMaxRetriesHitError will be thrown with all the errors that were thrown by the task function
+     *
+     * @param taskFn - The function to run
+     * @param onError - The callback to call when an error occurs
+     *
+     * @throws An {@link ExponentialBackoffMaxRetriesHitError} with all the errors that were thrown by the task function
+     * @throws An {@link ExponentialBackoffStoppedRetriesError} if the abort signal is activated
+     *
+     * @returns The result of the function
+     */
+    async run<T>(
+        taskFn: (callbackParameters: ExponentialBackoffCallbackParameters) => Promise<T>,
+        onError = (_error: Error): void => {},
+    ): Promise<T> {
+        // Initialize an abort signal to allow the task function to be aborted
+        const abortController = new AbortController();
+        const stopRetries = abortController.abort.bind(abortController);
+
+        // Initialize an empty array to store the errors
+        const errors: Error[] = [];
+
+        // Initialize the attempt counter
+        let attempt = 0;
+
+        // If the max attempts is 0, we should continue indefinitely.
+        const unlimitedAttempts = this.#options.maxAttempts === 0;
+
+        // Loop until we succeed, hit the max attempts, or the abort signal is activated
+        while (true) {
+            try {
+                // Await the promise before returning so its execution context remains in the try-catch
+                // If we didn't await, this `run` function would successfully return and any errors would not be caught here.
+                return await taskFn({ stopRetries });
+            } catch (error) {
+                // Store the error in case we fail every attempt
+                const errorInstance = error instanceof Error ? error : new Error(`${error}`);
+                onError(errorInstance);
+
+                // If we have unlimited attempts, don't append this to the errors array to prevent a memory leak.
+                if (!unlimitedAttempts) {
+                    errors.push(errorInstance);
+                }
+            }
+
+            // Calculate the count for next attempt. Do this now so we can exit before waiting and before running the next attempt.
+            const nextAttemptCount = attempt + 1;
+            const nextAttemptExceedsMaxAttempts = nextAttemptCount >= this.#options.maxAttempts;
+
+            // If the next attempt exceeds the max attempts, break out of the loop
+            if (!unlimitedAttempts && nextAttemptExceedsMaxAttempts) {
+                break;
+            }
+
+            // Check if the abort signal has been aborted
+            if (abortController.signal.aborted) {
+                // Throw an error if the abort signal has been aborted
+                throw new ExponentialBackoffStoppedRetriesError(abortController.signal.reason);
+            }
+
+            // Wait before going to the next attempt
+            const delay = ExponentialBackoff.calculateDelay(this.#options, attempt);
+            await new Promise((resolve) => setTimeout(resolve, delay));
+
+            attempt++;
+        }
+
+        // We completed the loop without ever succeeding. Throw an ExponentialBackoffMaxRetriesHitError with all the errors we got
+        throw new ExponentialBackoffMaxRetriesHitError(errors);
+    }
+}
+
+export type ExponentialBackoffOptions = {
+
+    /**
+     * The maximum delay between attempts in milliseconds
+     */
+    maxDelay: number;
+
+    /**
+     * The maximum number of attempts. Passing 0 will result in infinite attempts.
+     */
+    maxAttempts: number;
+
+    /**
+     * The base delay between attempts in milliseconds
+     */
+    baseDelay: number;
+
+    /**
+     * The growth rate of the delay
+     */
+    growthRate: number;
+
+    /**
+     * The jitter of the delay as a percentage of growthRate. The jitter is subtracted from the delay.
+     */
+    jitter: number;
+};
+
+/**
+ * The function to call to stop the retries.
+ * This mimics the AbortSignal.abort function by taking in a reason for stopping
+ *
+ * @param reason - The reason for stopping the retries.
+ */
+export type ExponentialBackoffStopRetriesFunction = (reason: unknown) => void;
+
+/**
+ * The parameters for the task function
+ *
+ * @param stopRetries - The function to call to stop the retries
+ */
+export type ExponentialBackoffCallbackParameters = {
+    stopRetries: ExponentialBackoffStopRetriesFunction;
+};
diff --git a/source/index.ts b/source/index.ts
index a29e6ae..dbbc78c 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -1,3 +1,4 @@
+export * from './exponential-backoff.ts';
 export * from './extended-json.ts';
 export * from './script.ts';
 export * from './sse-session/index.ts';
diff --git a/test/exponential-backoff.test.ts b/test/exponential-backoff.test.ts
new file mode 100644
index 0000000..7c29a96
--- /dev/null
+++ b/test/exponential-backoff.test.ts
@@ -0,0 +1,595 @@
+import { expect, test, vi } from 'vitest';
+import { ExponentialBackoff } from '../source/exponential-backoff.ts';
+import { ExponentialBackoffMaxRetriesHitError, ExponentialBackoffStoppedRetriesError } from '../source/errors.ts';
+
+/**
+ * A valid options object that satisfies {@link ExponentialBackoff.validateOptions}.
+ */
+const validExponentialBackoffOptions = {
+    maxDelay: 10_000,
+    maxAttempts: 10,
+    baseDelay: 1_000,
+    growthRate: 2,
+    jitter: 0.1,
+};
+
+/**
+ * Tests that the static {@link ExponentialBackoff.run} helper creates a throwaway instance
+ * with library defaults (including the default 1000ms base delay) when no options are passed.
+ */
+const testExponentialBackoffRunUsesDefaultOptions = async (): Promise<void> => {
+    // Fake timers let us advance time without waiting real seconds between retries.
+    vi.useFakeTimers();
+    // Pin Math.random to 0 so jitter does not reduce the default delay.
+    vi.spyOn(Math, 'random').mockReturnValue(0);
+
+    try {
+        // The wrapped function fails on its first invocation and succeeds on the second.
+        // That forces ExponentialBackoff.run down the retry path using default options.
+        const rejectThenResolveFn = vi.fn().mockRejectedValueOnce(new Error('retry me'))
+.mockResolvedValueOnce('static-result');
+
+        // Call the static helper with no onError and no options — defaults apply entirely.
+        const promise = ExponentialBackoff.run(rejectThenResolveFn);
+
+        // Yield one microtask so the first (immediate) attempt completes and schedules the retry timer.
+        await Promise.resolve();
+        expect(rejectThenResolveFn).toHaveBeenCalledTimes(1);
+
+        // Default baseDelay is 1000ms; advancing less would not trigger the retry yet.
+        await vi.advanceTimersByTimeAsync(1_000);
+
+        // The retry should have succeeded and returned the resolved value from the mock.
+        await expect(promise).resolves.toBe('static-result');
+        expect(rejectThenResolveFn).toHaveBeenCalledTimes(2);
+    } finally {
+        vi.useRealTimers();
+        vi.restoreAllMocks();
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.run} accepts a partial options object and merges it
+ * with defaults, still retrying when only some fields are overridden.
+ */
+const testExponentialBackoffRunWithPartialOptions = async (): Promise<void> => {
+    // Same fail-then-succeed pattern; we only care that partial options still enable a retry.
+    const rejectThenResolveFn = vi.fn().mockRejectedValueOnce(new Error('retry me'))
+.mockResolvedValueOnce('done');
+
+    // baseDelay/jitter of 0 skip real waiting; maxAttempts: 3 gives headroom for one retry.
+    // onError is explicitly undefined to verify the default no-op handler is used.
+    const result = await ExponentialBackoff.run(rejectThenResolveFn, undefined, {
+        baseDelay: 0,
+        jitter: 0,
+        maxAttempts: 3,
+    });
+
+    expect(result).toBe('done');
+    expect(rejectThenResolveFn).toHaveBeenCalledTimes(2);
+};
+
+/**
+ * Tests that calling {@link ExponentialBackoff.run} on a constructed instance applies
+ * the instance's stored options when no per-run options are supplied.
+ */
+const testExponentialBackoffInstanceRunUsesDefaultOnError = async (): Promise<void> => {
+    const rejectThenResolveFn = vi.fn().mockRejectedValueOnce(new Error('retry me'))
+.mockResolvedValueOnce('instance-result');
+
+    // Options live on the instance; run(fn) should read them instead of static defaults.
+    const backoff = new ExponentialBackoff({ baseDelay: 0, jitter: 0, maxAttempts: 3 });
+
+    const result = await backoff.run(rejectThenResolveFn);
+
+    expect(result).toBe('instance-result');
+    expect(rejectThenResolveFn).toHaveBeenCalledTimes(2);
+};
+
+/**
+ * Tests the happy path: the wrapped function succeeds immediately and no retry machinery runs.
+ */
+const testExponentialBackoffSucceedsOnFirstAttempt = async (): Promise<void> => {
+    // Always resolves — never enters the catch/retry branch.
+    const resolveFn = vi.fn(async () => 'success');
+    const onError = vi.fn();
+
+    const result = await ExponentialBackoff.run(resolveFn, onError, {
+        baseDelay: 0,
+        jitter: 0,
+    });
+
+    expect(result).toBe('success');
+    expect(resolveFn).toHaveBeenCalledOnce();
+    expect(onError).not.toHaveBeenCalled();
+};
+
+/**
+ * Tests that retries continue across multiple failures until the function eventually resolves.
+ */
+const testExponentialBackoffRetriesUntilSuccess = async (): Promise<void> => {
+    // Three invocations: two rejections then a success on the third call.
+    const tripleRejectFn = vi
+        .fn()
+        .mockRejectedValueOnce(new Error('attempt 1'))
+        .mockRejectedValueOnce(new Error('attempt 2'))
+        .mockResolvedValueOnce('success');
+
+    // maxAttempts: 5 is high enough that we stop because fn succeeded, not because we hit the cap.
+    const result = await ExponentialBackoff.run(tripleRejectFn, () => {}, {
+        baseDelay: 0,
+        jitter: 0,
+        maxAttempts: 5,
+    });
+
+    expect(result).toBe('success');
+    expect(tripleRejectFn).toHaveBeenCalledTimes(3);
+};
+
+/**
+ * Tests that the onError callback is invoked once for every failed attempt, including the last one
+ * before an ExponentialBackoffMaxRetriesHitError is thrown to the caller.
+ */
+const testExponentialBackoffCallsOnErrorForEachFailure = async (): Promise<void> => {
+    const error = new Error('temporary failure');
+
+    // Always rejects with the same error — we will exhaust all attempts.
+    const rejectFn = vi.fn().mockRejectedValue(error);
+    const onError = vi.fn();
+
+    // maxAttempts: 3 means three tries total, all of which will fail.
+    await expect(ExponentialBackoff.run(rejectFn, onError, {
+            baseDelay: 0,
+            jitter: 0,
+            maxAttempts: 3,
+        })).rejects.toThrow(ExponentialBackoffMaxRetriesHitError);
+
+    expect(onError).toHaveBeenCalledTimes(3);
+    expect(onError).toHaveBeenCalledWith(error);
+};
+
+/**
+ * Tests that when all attempts are exhausted the caller receives an ExponentialBackoffMaxRetriesHitError
+ * with every task error preserved in order on the cause.
+ */
+const testExponentialBackoffThrowsMaxRetriesHitErrorWhenExhausted = async (): Promise<void> => {
+    const firstError = new Error('first');
+    const lastError = new Error('last');
+
+    // Two distinct errors so we can prove both are collected, not just the last one.
+    const doubleRejectFn = vi.fn().mockRejectedValueOnce(firstError)
+.mockRejectedValueOnce(lastError);
+
+    try {
+        await ExponentialBackoff.run(doubleRejectFn, () => {}, {
+            baseDelay: 0,
+            jitter: 0,
+            maxAttempts: 2,
+        });
+        expect.fail('Expected ExponentialBackoffMaxRetriesHitError to be thrown');
+    } catch (error) {
+        expect(error).toBeInstanceOf(ExponentialBackoffMaxRetriesHitError);
+        expect((error as ExponentialBackoffMaxRetriesHitError).cause).toEqual([ firstError, lastError ]);
+    }
+
+    expect(doubleRejectFn).toHaveBeenCalledTimes(2);
+};
+
+/**
+ * Tests that rejections which are not Error instances are coerced to Error before onError runs,
+ * so callers always observe a consistent error type in the callback.
+ */
+const testExponentialBackoffWrapsNonErrorThrows = async (): Promise<void> => {
+    // Reject with a plain string — not an Error subclass.
+    const rejectedFn = vi.fn().mockRejectedValue('not-an-error');
+    const onError = vi.fn();
+
+    // Single attempt — we fail fast and inspect what onError received.
+    try {
+        await ExponentialBackoff.run(rejectedFn, onError, {
+            baseDelay: 0,
+            jitter: 0,
+            maxAttempts: 1,
+        });
+        expect.fail('Expected ExponentialBackoffMaxRetriesHitError to be thrown');
+    } catch (error) {
+        expect(error).toBeInstanceOf(ExponentialBackoffMaxRetriesHitError);
+        const [ wrappedError ] = (error as ExponentialBackoffMaxRetriesHitError).cause as Error[];
+        expect(wrappedError).toBeInstanceOf(Error);
+        expect(wrappedError.message).toBe('not-an-error');
+    }
+
+    expect(onError).toHaveBeenCalledOnce();
+    expect(onError.mock.calls[0][0]).toBeInstanceOf(Error);
+    expect(onError.mock.calls[0][0].message).toBe('not-an-error');
+};
+
+/**
+ * Tests that when the task function succeeds and the abort signal is aborted, the result is returned
+ * and the onError callback is not called.
+ */
+const testExponentialBackoffRunSuccessAndAbortSignal = async (): Promise<void> => {
+    // Define the function which aborts the exponential backoff and succeeds
+    const abortAndSucceedFn = vi.fn(({ stopRetries }) => {
+        stopRetries(new Error('retry me'));
+
+        return Promise.resolve('success');
+    });
+    const onErrorFn = vi.fn();
+
+    // Run the exponential backoff with the function and the onError callback
+    const result = await ExponentialBackoff.run(abortAndSucceedFn, onErrorFn, {
+        baseDelay: 0,
+        jitter: 0,
+    });
+
+    // Expect the result to be the success message
+    expect(result).toBe('success');
+    expect(abortAndSucceedFn).toHaveBeenCalledOnce();
+
+    // Expect the onError callback to not have been called
+    expect(onErrorFn).not.toHaveBeenCalled();
+};
+
+/**
+ * Tests that when the abort signal is aborted with an error, an ExponentialBackoffStoppedRetriesError is thrown
+ * with the error as the message.
+ */
+const testExponentialBackoffRunWithAbortSignal = async (): Promise<void> => {
+    // Define the function which aborts the exponential backoff and throws an error
+    const abortAndThrowFn = vi.fn(({ stopRetries }) => {
+        stopRetries(new Error('exponential backoff aborted'));
+        throw new Error('error message');
+    });
+    const onErrorFn = vi.fn();
+
+    // Define the expected error
+    const expectedError = new ExponentialBackoffStoppedRetriesError(new Error('exponential backoff aborted'));
+
+    // Run the exponential backoff with the function and the onError callback and expect the error to be thrown
+    await expect(ExponentialBackoff.run(abortAndThrowFn, onErrorFn, {
+            baseDelay: 0,
+            jitter: 0,
+        })).rejects.toThrow(expectedError);
+
+    // Expect the onError callback to have been called once with the error
+    expect(onErrorFn).toHaveBeenCalledOnce();
+    expect(onErrorFn.mock.calls[0][0]).toBeInstanceOf(Error);
+    expect(onErrorFn.mock.calls[0][0].message).toBe('error message');
+
+    // Expect the function to have been called once and not to have resolved
+    expect(abortAndThrowFn).toHaveBeenCalledOnce();
+    expect(abortAndThrowFn).not.toHaveResolved();
+};
+
+/**
+ * Tests that when the abort signal is aborted with a string, an ExponentialBackoffStoppedRetriesError is thrown
+ * with the string as the message.
+ */
+const testExponentialBackoffRunAbortedStringCreatesError = async (): Promise<void> => {
+    // Define the function which aborts the exponential backoff and throws an error
+    const abortAndThrowStringFn = vi.fn(({ stopRetries }) => {
+        stopRetries('exponential backoff aborted');
+
+        // eslint-disable-next-line
+        throw 'error message';
+    });
+    const onErrorFn = vi.fn();
+
+    // Define the expected error, Note that we "stopRetries" with just a string, not an error. They are treated equivalently.
+    const expectedError = new ExponentialBackoffStoppedRetriesError(new Error('exponential backoff aborted'));
+
+    // Run the exponential backoff with the function and the onError callback and expect the error to be thrown
+    await expect(ExponentialBackoff.run(abortAndThrowStringFn, onErrorFn, {
+            baseDelay: 0,
+            jitter: 0,
+        })).rejects.toThrow(expectedError);
+
+    // Expect the onError callback to have been called once with the error
+    expect(onErrorFn).toHaveBeenCalledOnce();
+    expect(onErrorFn.mock.calls[0][0]).toBeInstanceOf(Error);
+    expect(onErrorFn.mock.calls[0][0].message).toBe('error message');
+
+    // Expect the function to have been called once and not to have resolved
+    expect(abortAndThrowStringFn).toHaveBeenCalledOnce();
+    expect(abortAndThrowStringFn).not.toHaveResolved();
+};
+
+/**
+ * Tests the {@link ExponentialBackoff.from} factory and subsequent instance {@link ExponentialBackoff.run}
+ * as an alternative to the static helper.
+ */
+const testExponentialBackoffFromAndInstanceRun = async (): Promise<void> => {
+    const successfullyResolve = vi.fn(async () => 42);
+
+    // from() is a convenience constructor; run() on the result should behave like the static path.
+    const backoff = ExponentialBackoff.from({
+        baseDelay: 0,
+        jitter: 0,
+    });
+
+    const result = await backoff.run(successfullyResolve);
+
+    expect(result).toBe(42);
+    expect(successfullyResolve).toHaveBeenCalledOnce();
+};
+
+/**
+ * Tests that maxAttempts: 0 disables the attempt cap so retries continue until the function succeeds.
+ */
+const testExponentialBackoffRetriesIndefinitelyWhenMaxAttemptsIsZero = async (): Promise<void> => {
+    // Four invocations: three failures then success — would exceed a cap of 3 if one existed.
+    const tripleRejectThenResolveFn = vi
+        .fn()
+        .mockRejectedValueOnce(new Error('attempt 1'))
+        .mockRejectedValueOnce(new Error('attempt 2'))
+        .mockRejectedValueOnce(new Error('attempt 3'))
+        .mockResolvedValueOnce('eventually');
+
+    const result = await ExponentialBackoff.run(tripleRejectThenResolveFn, () => {}, {
+        baseDelay: 0,
+        jitter: 0,
+        maxAttempts: 0,
+    });
+
+    expect(result).toBe('eventually');
+    expect(tripleRejectThenResolveFn).toHaveBeenCalledTimes(4);
+};
+
+/**
+ * Tests the delay formula: each retry waits baseDelay * growthRate^attemptIndex milliseconds
+ * (with jitter disabled so the math is exact).
+ */
+const testExponentialBackoffIncreasesDelayExponentially = async (): Promise<void> => {
+    vi.useFakeTimers();
+    vi.spyOn(Math, 'random').mockReturnValue(0.5);
+
+    try {
+        const doubleRejectThenResolveFn = vi
+            .fn()
+            .mockRejectedValueOnce(new Error('attempt 1'))
+            .mockRejectedValueOnce(new Error('attempt 2'))
+            .mockResolvedValueOnce('success');
+
+        const promise = ExponentialBackoff.run(doubleRejectThenResolveFn, () => {}, {
+            baseDelay: 100,
+            growthRate: 2,
+            jitter: 0,
+            maxDelay: 10_000,
+            maxAttempts: 5,
+        });
+
+        // Attempt 0 fires synchronously on the first microtask tick.
+        await Promise.resolve();
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(1);
+
+        // After attempt 0 fails, delay = 100 * 2^0 = 100ms before attempt 1.
+        await vi.advanceTimersByTimeAsync(100);
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(2);
+
+        // After attempt 1 fails, delay = 100 * 2^1 = 200ms before attempt 2.
+        await vi.advanceTimersByTimeAsync(200);
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(3);
+
+        await expect(promise).resolves.toBe('success');
+    } finally {
+        vi.useRealTimers();
+        vi.restoreAllMocks();
+    }
+};
+
+/**
+ * Tests that computed delay never exceeds maxDelay even when exponential growth would go higher.
+ */
+const testExponentialBackoffCapsDelayAtMaxDelay = async (): Promise<void> => {
+    vi.useFakeTimers();
+    vi.spyOn(Math, 'random').mockReturnValue(0.5);
+
+    try {
+        const doubleRejectThenResolveFn = vi
+            .fn()
+            .mockRejectedValueOnce(new Error('attempt 1'))
+            .mockRejectedValueOnce(new Error('attempt 2'))
+            .mockResolvedValueOnce('success');
+
+        const promise = ExponentialBackoff.run(doubleRejectThenResolveFn, () => {}, {
+            baseDelay: 1_000,
+            growthRate: 4,
+            jitter: 0,
+            maxDelay: 2_000,
+            maxAttempts: 5,
+        });
+
+        await Promise.resolve();
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(1);
+
+        // attempt 0: 1000 * 4^0 = 1000ms, below the 2000ms cap.
+        await vi.advanceTimersByTimeAsync(1_000);
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(2);
+
+        // attempt 1: uncapped would be 4000ms but maxDelay clamps to 2000ms.
+        await vi.advanceTimersByTimeAsync(2_000);
+        expect(doubleRejectThenResolveFn).toHaveBeenCalledTimes(3);
+
+        await expect(promise).resolves.toBe('success');
+    } finally {
+        vi.useRealTimers();
+        vi.restoreAllMocks();
+    }
+};
+
+/**
+ * Tests that jitter subtracts up to jitter * cappedDelay from the capped delay based on Math.random.
+ */
+const testExponentialBackoffAppliesJitter = async (): Promise<void> => {
+    vi.useFakeTimers();
+    // random = 1 → full 10% reduction: 1000 - (1 * 0.1 * 1000) = 900ms.
+    vi.spyOn(Math, 'random').mockReturnValue(1);
+
+    try {
+        const rejectThenResolveFn = vi.fn().mockRejectedValueOnce(new Error('attempt 1'))
+.mockResolvedValueOnce('success');
+
+        const promise = ExponentialBackoff.run(rejectThenResolveFn, () => {}, {
+            baseDelay: 1_000,
+            growthRate: 1,
+            jitter: 0.1,
+            maxDelay: 10_000,
+            maxAttempts: 3,
+        });
+
+        await Promise.resolve();
+        expect(rejectThenResolveFn).toHaveBeenCalledTimes(1);
+
+        // Advancing 899ms is one ms short of the jittered delay; 900ms triggers the retry.
+        await vi.advanceTimersByTimeAsync(899);
+        expect(rejectThenResolveFn).toHaveBeenCalledTimes(1);
+
+        await vi.advanceTimersByTimeAsync(1);
+        expect(rejectThenResolveFn).toHaveBeenCalledTimes(2);
+
+        await expect(promise).resolves.toBe('success');
+    } finally {
+        vi.useRealTimers();
+        vi.restoreAllMocks();
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.validateOptions} accepts valid options, including boundary values of 0 and 1.
+ */
+const testExponentialBackoffValidateOptionsAcceptsValidOptions = (): void => {
+    const validCases = [
+        validExponentialBackoffOptions,
+        {
+            ...validExponentialBackoffOptions,
+            maxDelay: 0,
+            maxAttempts: 0,
+            baseDelay: 0,
+            growthRate: 0,
+            jitter: 0,
+        },
+        {
+            ...validExponentialBackoffOptions,
+            jitter: 1,
+        },
+    ] as const;
+
+    for (const options of validCases) {
+        expect(() => ExponentialBackoff.validateOptions(options)).not.toThrow();
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.validateOptions} rejects negative numeric options.
+ */
+const testExponentialBackoffValidateOptionsRejectsNegativeValues = (): void => {
+    // Define our test cases with each value being less than 0
+    const negativeCases = [
+        { field: 'maxDelay', value: -1 },
+        { field: 'maxAttempts', value: -1 },
+        { field: 'baseDelay', value: -1 },
+        { field: 'growthRate', value: -1 },
+    ] as const;
+
+    // Iterate through the test cases and expect an error to be thrown
+    for (const { field, value } of negativeCases) {
+        expect(() =>
+            ExponentialBackoff.validateOptions({
+                ...validExponentialBackoffOptions,
+                [field]: value,
+            })).toThrow(`${field} must be not less than 0`);
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.validateOptions} rejects jitter below 0 or above 1.
+ */
+const testExponentialBackoffValidateOptionsRejectsInvalidJitter = (): void => {
+    // Define our test cases with each value being less than 0 or greater than 1
+    const invalidJitterCases: Array<{ value: number }> = [{ value: -0.1 }, { value: 1.1 }];
+
+    // Iterate through the test cases and expect an error to be thrown
+    for (const { value } of invalidJitterCases) {
+        expect(() =>
+            ExponentialBackoff.validateOptions({
+                ...validExponentialBackoffOptions,
+                jitter: value,
+            })).toThrow('jitter must be not less than 0 or greater than 1');
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.validateOptions} rejects non-finite values such as Infinity.
+ */
+const testExponentialBackoffValidateOptionsRejectsNonFiniteValues = (): void => {
+    // Define our test cases with each value being Infinity
+    const nonFiniteCases = [
+        { field: 'maxDelay', value: Infinity },
+        { field: 'maxAttempts', value: Infinity },
+        { field: 'baseDelay', value: Infinity },
+        { field: 'growthRate', value: Infinity },
+        { field: 'jitter', value: Infinity },
+    ] as const;
+
+    // Iterate through the test cases and expect an error to be thrown
+    for (const { field, value } of nonFiniteCases) {
+        expect(() =>
+            ExponentialBackoff.validateOptions({
+                ...validExponentialBackoffOptions,
+                [field]: value,
+            })).toThrow(`${field} must be a finite number`);
+    }
+};
+
+/**
+ * Tests that {@link ExponentialBackoff.validateOptions} rejects NaN, which is also non-finite.
+ */
+const testExponentialBackoffValidateOptionsRejectsNaN = (): void => {
+    // Define our test cases with each value being NaN
+    const nanCases = [
+        { field: 'maxDelay', value: Number.NaN },
+        { field: 'maxAttempts', value: Number.NaN },
+        { field: 'baseDelay', value: Number.NaN },
+        { field: 'growthRate', value: Number.NaN },
+        { field: 'jitter', value: Number.NaN },
+    ] as const;
+
+    // Iterate through the test cases and expect an error to be thrown
+    for (const { field, value } of nanCases) {
+        expect(() =>
+            ExponentialBackoff.validateOptions({
+                ...validExponentialBackoffOptions,
+                [field]: value,
+            })).toThrow(`${field} must be a finite number`);
+    }
+};
+
+const runTests = async (): Promise<void> => {
+    test('ExponentialBackoff.run: delegates to a new instance using default options', testExponentialBackoffRunUsesDefaultOptions);
+    test('ExponentialBackoff.run: retries and succeeds with partial options', testExponentialBackoffRunWithPartialOptions);
+    test('ExponentialBackoff.run: uses the instance default onError when omitted', testExponentialBackoffInstanceRunUsesDefaultOnError);
+    test('ExponentialBackoff: returns the result on first success', testExponentialBackoffSucceedsOnFirstAttempt);
+    test('ExponentialBackoff: retries until the function succeeds', testExponentialBackoffRetriesUntilSuccess);
+    test('ExponentialBackoff: calls onError for each failed attempt', testExponentialBackoffCallsOnErrorForEachFailure);
+    test(
+        'ExponentialBackoff: throws ExponentialBackoffMaxRetriesHitError when max attempts are exhausted',
+        testExponentialBackoffThrowsMaxRetriesHitErrorWhenExhausted,
+    );
+    test('ExponentialBackoff: wraps non-Error throws before calling onError', testExponentialBackoffWrapsNonErrorThrows);
+    test('ExponentialBackoff: succeeds and aborts with abort signal', testExponentialBackoffRunSuccessAndAbortSignal);
+    test('ExponentialBackoff: aborts with abort signal', testExponentialBackoffRunWithAbortSignal);
+    test('ExponentialBackoff: aborts with aborted string creates error', testExponentialBackoffRunAbortedStringCreatesError);
+    test('ExponentialBackoff: works via from and instance run', testExponentialBackoffFromAndInstanceRun);
+    test('ExponentialBackoff: retries indefinitely when maxAttempts is 0', testExponentialBackoffRetriesIndefinitelyWhenMaxAttemptsIsZero);
+    test('ExponentialBackoff: increases delay exponentially between attempts', testExponentialBackoffIncreasesDelayExponentially);
+    test('ExponentialBackoff: caps delay at maxDelay', testExponentialBackoffCapsDelayAtMaxDelay);
+    test('ExponentialBackoff: subtracts jitter from the capped delay', testExponentialBackoffAppliesJitter);
+    test('ExponentialBackoff.validateOptions: accepts valid options', testExponentialBackoffValidateOptionsAcceptsValidOptions);
+    test('ExponentialBackoff.validateOptions: rejects negative values', testExponentialBackoffValidateOptionsRejectsNegativeValues);
+    test('ExponentialBackoff.validateOptions: rejects invalid jitter', testExponentialBackoffValidateOptionsRejectsInvalidJitter);
+    test('ExponentialBackoff.validateOptions: rejects Infinity', testExponentialBackoffValidateOptionsRejectsNonFiniteValues);
+    test('ExponentialBackoff.validateOptions: rejects NaN', testExponentialBackoffValidateOptionsRejectsNaN);
+};
+
+await runTests();