Durability

Durability is an open-source toolkit for SQLite-backed Cloudflare Durable Objects. Its main package persists operations and logical alarms, retries failures, deduplicates stable IDs, and exposes typed results while sharing the Durable Object’s single physical alarm safely.

npm install durability

Durable operations

Named alarms

Schedule independent logical alarms through one physical Durable Object alarm.

Typed RPC transforms

Compose caller and callee behavior around Durable Object and Worker RPC.

Safety tooling

Enforce alarm ownership and reversible SQLite migrations with Oxlint.

Minimal operation

import { DurableObject } from 'cloudflare:workers';
import { createDurability, type DurableHandler } from 'durability';

type ResizeInput = { imageId: string };

export class ImageJobs extends DurableObject<Env> {
  private readonly durability = createDurability(this.ctx, {
    resizeImage: (async ({ id, payload, signal }) => {
      return this.env.IMAGES.resize(payload.imageId, {
        idempotencyKey: id,
        signal,
      });
    }) satisfies DurableHandler<ResizeInput, string>,
  });

  resize(imageId: string) {
    return this.durability.resizeImage({
      id: `resize:${imageId}`,
      payload: { imageId },
    });
  }

  alarm(info?: AlarmInvocationInfo) {
    return this.durability.alarm(info);
  }
}

The generated operation method resolves after registration commits. It does not wait for the handler result.

Requirements

Cloudflare Workers and a SQLite-backed Durable Object.
JSON-serializable operation payloads and results.
Direct delegation of the class alarm() method to Durability.
Stable operation IDs and idempotent external effects.

Open source

Continue with the quickstart, named alarms, or package map.