I'm sure this is a commonly asked question, but what is my best solution for local development and p

I'm sure this is a commonly asked question, but what is my best solution for local development and persistent state? My durable objects get erased after 10 seconds of inactivity, which seems to be known / intended behavior. But if my durable object is supposed to hold long-term persistent state (like user data), what is the common dev workflow for testing this locally?

Burrito•10/3/25, 9:23 PM

State shouldn't get erased, if you store them in storage.

Burrito•10/3/25, 9:25 PM

In memory state does get erased when the object is evicted, but that's true local or remote.

xormaskOP•10/3/25, 9:25 PM

Ah, I think I'm misunderstanding the semantics of the constructor.

xormaskOP•10/3/25, 9:26 PM

What is the best pattern for setting up initial persistent state in the durable object? The tutorial code seems to use conditionals on first read, but that feels a bit ugly.

Xxormask What is the best pattern for setting up initial persistent state in the durable ...

lnow•10/3/25, 9:28 PM

You can wrap some SQL queries with https://developers.cloudflare.com/durable-objects/api/state/#blockconcurrencywhile

Burrito•10/3/25, 9:30 PM

First read is fine. You can also do it in constructor, or have an explicit method for initializing which the invoking worker will call. It largely depends on the timing you want for the initialization.

xormaskOP•10/3/25, 9:31 PM

Got it. Confirmed that moving the .put() out of my constructor has fixed my "persistence" issue. Thanks for the help guys!

Llnow If I understand it correctly (please correct me if I'm wrong) you're suggesting ...

Larry•10/3/25, 10:23 PM

Durable Objects have access to fetch(). You would call the Worker from the DO the same way you would call the Worker from your client. That's what I'm most familiar with. I've only read about using Cloudflare RPC, but none of my production code uses it yet, so that's why I said "you might be able to..." when talking about RPC. I know you can call a DO from its host Worker via RPC. I just don't know if you can call the other way, but I think there is a way with this thing called EventTarget, but again, I know of it, but have never used it, or Cloudflare RPC for that matter.

PizzaConsole•10/4/25, 12:14 AM

FYI, not sure why this happened. It eventuialyl went away though...

LLarry Durable Objects have access to fetch(). You would call the Worker from the DO th...

cloudkite•10/4/25, 2:53 AM

I believe the new ctx.exports would let you call DO to worker, but haven’t tried it myself

demotime•10/4/25, 5:25 PM

hi all. Has anyone had issues with durable object alarms not firing? Works locally with wrangler but for some reason the alarms just never arrive once deployed. doing await this.getAlarm() shows a date in the past. I couldn't see any known issue or troubleshooting guide

Llnow You can wrap some SQL queries with https://developers.cloudflare.com/durable-obj...

Larry•10/4/25, 7:34 PM

Note, I'm pretty sure you don't need blockConcurrencyWhile if you are reading from the DO's own storage SQL. Only if you query and external SQL database do you need it.

adeola13.•10/4/25, 10:25 PM

Hello I have a question regarding how cloudflare counts "Records Read" as it relates to billing.

Let's say you have 20K records in the database. If everytime you run a query with some filters that only return one record each time, does cloudflare "bill" or "count" all 20K records every time as "Records Read" or only the one record returned?

Aadeola13.Hello I have a question regarding how cloudflare counts "Records Read" as it rel...

Larry•10/4/25, 10:45 PM

If you have a WHERE clause that uses an index it won't be 20 every time. If you have a clause like this: and the

id

id

column is indexed, it should only read 1 row in the table, but you may be charged for the index read as 1 row also.

Aadeola13.Hello I have a question regarding how cloudflare counts "Records Read" as it rel...

Larry•10/4/25, 10:48 PM

I believe the only time it will be one row read is if you have a "covering index" when all columns required by the query (including those in the SELECT, WHERE, ORDER BY, and GROUP BY clauses) are contained in the index itself.

Ddemotime hi all. Has anyone had issues with durable object alarms not firing? Works local...

Foxy•10/5/25, 6:43 AM

Yeah this happened to me too, I ended up just writing my own alarm utils that have guards that check things like alarm dates in the past

elunesarrow•10/5/25, 9:48 AM

Hi, is it true that I will get billed for compute for all of the 10s idle time before the DO gets wiped from memory and hibernated? My use case for DO is low frequency RPCs per DO (e.g. 1 req every few minutes), if I'm implementing one DO per user. Is it possible to make DOs hibernate faster? (e.g. 1s or less).

References:

From lifecycle page: "After 10 seconds of no incoming request or event, and all the above conditions satisfied, the Durable Object will transition into the hibernated state."
From pricing page: "A Durable Object incurs duration charges as long as the JavaScript object has to be in memory, either because it is actively handling a request, or because it cannot hibernate.".

Eelunesarrow Hi, is it true that I will get billed for compute for all of the 10s idle time b...

boop•10/5/25, 10:22 AM

You will not get billed for the idle time

Eelunesarrow Hi, is it true that I will get billed for compute for all of the 10s idle time b...

Larry•10/5/25, 11:42 AM

The key word is “has” in “has to be”. Notice it does not say “is in memory”. If you look on the lifecycle page there is a “idle, hibernatable” state that is NOT marked as billable.

elunesarrow•10/5/25, 4:04 PM

Oh right that blue box at the end of the page "...incurs charges only when it is actively running in-memory, or when it is idle in-memory and non-hibernateable (indicated as green rectangles in the diagram).". I skimmed this line and thought the "and" was not in bold, and missed the bracket completely. It's clearer now, thanks for the clarification!

zilch•10/6/25, 12:03 AM

why are DOs charged on wall time and not cpu time like workers? if i am making an LLM api call from DO vs workers, there would be an exponential difference in cost due to the two pricing strategies?

Zzilch why are DOs charged on wall time and not cpu time like workers? if i am making a...

1984 Ford Laser•10/6/25, 12:13 AM

You could call back out to a Worker to handle the LLM call then notify the DO when done?

Zzilch why are DOs charged on wall time and not cpu time like workers? if i am making a...

Larry•10/6/25, 12:19 AM

+1 to what @1984 Ford Laser said. I'd also encourage you to think about the different models. Workers are pure stateless. Every new request requires you to refetch all context from wherever it's stored. With DOs it's right there and stays there. DOs maintain WebSocket connections. DO's have input/output gates that allow you to intermix database reads, manipulate data with code, more database operations, etc. They hold on to cache differently. There are certain contexts where DOs actually cost less. However, even when they cost more, under load, I'm pretty sure the difference is not exponential. It's only exponential if you compare one request in isolation.

LLarry +1 to what @1984 Ford Laser said. I'd also encourage you to think about the diff...

João Castro•10/6/25, 12:25 AM

I'm also pretty sure DOs can be cheaper if you are doing CPU intensive workloads

JJoão Castro I'm also pretty sure DOs can be cheaper if you are doing CPU intensive workloads

1984 Ford Laser•10/6/25, 12:26 AM

Yeah Im pretty sure it costs ~$1.70 to run a Worker for an entire day (in pure CPU time only) whereas a DO is like ~$0.34 per day

1984 Ford Laser•10/6/25, 4:12 AM

Are Durable Object outgoing websocket connections part of the 6 concurrent outgoing connection limit of the runtime?

Zzilch why are DOs charged on wall time and not cpu time like workers? if i am making a...

gruntlord6•10/6/25, 3:38 PM

Durable Objects are stateful so while active they have to have everything running in reserved memory and storage, and they have a reasonable expectation to be accessible in that time (they could still disconnect or be evicted for other reasons). A worker is ethereal and there is never any requirement or expectation that you are served by the same worker. So it makes sense that workers are billed only for what you use since the server can kill your worker anytime it isn't processing requests and another one anywhere in the network can take that request in its place

gruntlord6•10/6/25, 3:40 PM

Like the others said, idle isn't counted towards this, and you can have workers handle things on behalf of the durable object if your worried about the time the request would be running

Zetax•10/7/25, 12:28 AM

Any updates on this? Would be a game changer https://github.com/cloudflare/workerd/issues/4864

GitHub

Feature Request: Add hibernation support for outgoing WebSocket con...

Summary Add hibernation support for outgoing WebSocket connections created by Durable Objects using new WebSocket(). Currently, hibernation only works for incoming WebSocket connections accepted vi...

Tero•10/7/25, 9:19 AM

Is there some known issues regarding durable object metrics / observability? When I navigate to durable objects in console, already in the listing I see error rates that make no sense. Selecting one of the durable object with seemingly high error rates I see a diagram like this.

Searcing the logs I find no errors or exceptions, and this 96% error rate does not correspond at all to what is happening in reality with the durable object.

TTero Is there some known issues regarding durable object metrics / observability? Whe...

boop•10/7/25, 11:35 AM

Not seeing the same

lnow•10/7/25, 3:30 PM

What are the costs of calling `storage.deleteAll()` ?Let's say I have 1M rows in a table, will I be billed for 1M rows written as all 1M rows must be deleted?
Are there any plans for read replicas for DOs?

Llnow 1. What are the costs of calling `storage.deleteAll()` ? Let's say I have 1M row...

lambrospetrou•10/7/25, 3:48 PM

Are there any plans for read replicas for DOs?

Yes, once D1 read replication is Generally Available, we will open up replicas for DOs too (or around that time), since the underlying infrastructure is the same. D1 read replication uses DO read replicas.

Burrito•10/7/25, 4:17 PM

That's exciting.

BBrayden Durable Objects will have a built in Studio in the dashboard next week if this f...

Jacob Marshall•10/7/25, 8:55 PM

Any chance we'll be seeing it this week?

Llnow 1. What are the costs of calling `storage.deleteAll()` ? Let's say I have 1M row...

1984 Ford Laser•10/7/25, 9:02 PM

To answer the first one:
https://developers.cloudflare.com/durable-objects/platform/pricing/#sqlite-storage-backend

JJacob Marshall Any chance we'll be seeing it this week? 🙂

Brayden•10/7/25, 9:11 PM

So.... it's ready, but...

just finishing an internal audit before we release

Jacob Marshall•10/7/25, 9:12 PM

Very exciting! I assume you can't really say how long those usually take haha?

Jacob Marshall•10/7/25, 9:13 PM

It's not like it's urgent to me, but it's still very exciting to see - coz it's long overdue

JJacob Marshall It's not like it's urgent to me, but it's still very exciting to see - coz it's ...

Brayden•10/7/25, 9:17 PM

am I allowed to say "this week" again?

Jacob Marshall•10/7/25, 9:43 PM

ZZetax Any updates on this? Would be a game changer https://github.com/cloudflare/worke...

plgingras88•10/7/25, 9:47 PM

I am in a hard release too, can't blame you Brayden ! Be proud it's a game changer feature.

BBrayden am I allowed to say "this week" again?

lambrospetrou•10/7/25, 10:18 PM

Brayden didn't learn yet not to give out ETAs

If there isn't an ETA, you cannot miss it.

11984 Ford Laser To answer the first one: `Deletes are counted as rows written.` https://develope...

lnow•10/8/25, 6:45 AM

I know how deletes are billed. What I don't know is if calling

deleteAll()

deleteAll()

which effectively removes DO is treated the same or not.

grrowl•10/8/25, 7:38 AM

does anyone know how to override the RPC Timeout? We're streaming data using ReadableStream over RPC, but the 100s time limit is too low for long-running AI responses. is defined here: https://developers.cloudflare.com/api/resources/zones/subresources/settings/models/proxy_read_timeout/

Cloudflare API | Zones › Settings › ProxyReadTimeout

Interact with Cloudflare's products and services via the Cloudflare API

Marak•10/8/25, 8:09 AM

Is it possible to view an account wide “Service Map” or “Topology View” showing all Workers, Durable Objects, and their bindings/dependencies in the dashboard?

Currently, each individual Worker page in the dashboard displays its bindings and dependencies (Durable Objects, KV, R2, etc.), which is helpful, but there’s no system-wide view that connects them all.

MMarak Is it possible to view an account wide “Service Map” or “Topology View” showing ...

lambrospetrou•10/8/25, 10:01 AM

I don't think this exists right now, although it's been discussed a couple of times.

Llambrospetrou I don't think this exists right now, although it's been discussed a couple of ti...

Marak•10/8/25, 10:21 AM

With many Worker and Durable Object classes, it’s challenging to get a high-level picture of how everything fits together.

MMarak With many Worker and Durable Object classes, it’s challenging to get a high-leve...

lambrospetrou•10/8/25, 11:10 AM

The UI gets a lot of love lately, so I am sure (or I hope) this will get some attention at some point as well.