Durable Objects
A stateful edge computing primitive introduced by Cloudflare. Each instance is globally unique and provides strong consistency, enabling coordination of shared state across Workers and supporting stateful serverless application scenarios.
Core Facts
Cloudflare Durable Objects assign a globally unique ID to each object and guarantee that all requests with the same ID are routed to the same instance, thereby achieving strongly consistent state storage.
Durable Objects are stateful compute units on the Cloudflare Workers platform; each object has its own in-memory state and persistent storage, and only one instance of the same object ID runs at any given time.
Timeline (last 90 days)
After stripping static tables at build time, each isolate frees about 80MB of V8 heap.
A Durable Object is a globally unique, single-threaded V8 isolate, addressed by name, with its own private SQLite database and persistent timers.
Each Durable Object isolate has a hard 128MB heap memory limit.
The team mapped cloudflare:workers to a 10-line stub class in deno.json, enabling deno test to run native tests directly against Durable Object classes.
SQLite queries in a Durable Object are microsecond-level synchronous C++ calls rather than network round trips.
Only a Durable Object's alarm() runs in a clean root IoContext, with no inherited cdn-loop header and no 30-second post-response wall-clock limit, provided that alarm() starts the task via doCtx.waitUntil and then exits immediately.
BrowserPair's cloud components use Cloudflare Workers, Durable Objects and D1.
Cloudflare Workers is a serverless runtime running on the edge network; Durable Objects provide strongly consistent stateful objects; D1 is a managed relational database based on SQLite.
Cloudflare uses Durable Objects to provide state persistence for long-running security investigations, supporting the maintenance of context across multiple agent invocations.
In the Cloudflare system, when a Durable Object is unavailable, exponential backoff retries are used, and after three attempts it is escalated to a human.
16 more timeline events
All Facts (20)
Cloudflare Durable Objects assign a globally unique ID to each object and guarantee that all requests with the same ID are routed to the same instance, thereby achieving strongly consistent state storage.
65%VerifiedDurable Objects are stateful compute units on the Cloudflare Workers platform; each object has its own in-memory state and persistent storage, and only one instance of the same object ID runs at any given time.
65%UnverifiedCloudflare Workers生态中的Durable Objects为有状态的Agent工作流提供强一致性的状态存储
90%UnverifiedOnly a Durable Object's alarm() runs in a clean root IoContext, with no inherited cdn-loop header and no 30-second post-response wall-clock limit, provided that alarm() starts the task via doCtx.waitUntil and then exits immediately.
50%UnverifiedA Durable Object is a globally unique, single-threaded V8 isolate, addressed by name, with its own private SQLite database and persistent timers.
50%UnverifiedSQLite queries in a Durable Object are microsecond-level synchronous C++ calls rather than network round trips.
50%UnverifiedThe team mapped cloudflare:workers to a 10-line stub class in deno.json, enabling deno test to run native tests directly against Durable Object classes.
50%UnverifiedEach Durable Object isolate has a hard 128MB heap memory limit.
50%UnverifiedAfter stripping static tables at build time, each isolate frees about 80MB of V8 heap.
50%UnverifiedCloudflare Workers is a serverless runtime running on the edge network; Durable Objects provide strongly consistent stateful objects; D1 is a managed relational database based on SQLite.
50%UnverifiedBrowserPair's cloud components use Cloudflare Workers, Durable Objects and D1.
50%UnverifiedCloudflare uses Durable Objects to provide state persistence for long-running security investigations, supporting the maintenance of context across multiple agent invocations.
50%UnverifiedIn the Cloudflare system, when a Durable Object is unavailable, exponential backoff retries are used, and after three attempts it is escalated to a human.
50%UnverifiedThe recommended hybrid architecture is to use Durable Objects for short-term context and homelab/Qdrant for long-term knowledge, establishing a memory hierarchy and using TTL policies to clean up expired session data.
50%UnverifiedDurable Objects automatically hibernate when there are no requests for a few seconds, saving memory state via checkpointing, dropping CPU usage to zero, with wake-up time ranging from 10–100 ms depending on state size.
50%UnverifiedThe design constraint of the hibernation mechanism is: never rely on in-memory state surviving between requests, and all critical state must be written to persistent storage before returning.
50%UnverifiedThere are three main isolation models for Durable Objects: Per-Session, Per-User, and Per-Tenant.
50%UnverifiedThe Agents SDK provides a built-in SQL interface for Durable Objects.
50%UnverifiedIn-memory JavaScript variables, uncommitted transactions, temporary tables, and prepared statements within Durable Objects are not persisted when the DO hibernates.
50%UnverifiedCloudflare Workers + Durable Objects latency is in the single-digit millisecond range, but query capabilities are limited (a SQL subset with no support for joins or complex transactions).
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