Note that in contrast to JSON-oriented databases, KV just stores the bytes. You can't query on nes

Note that in contrast to JSON-oriented databases, KV just stores the bytes. You can't query on nested JSON fields or anything because KV has no idea it's JSON, it's just storing the content.

IIsaac McFadyen At its core, KV stores bytes so any value (including JSON) that can be serialize...

Sam•3/27/25, 8:43 PM

That’s good to know, do you have an example showing json value into KV? How do I translate the object into a Value?

IIsaac McFadyen Note that in contrast to JSON-oriented databases, KV just *stores* the bytes. Yo...

Sam•3/27/25, 8:44 PM

That’s not an issue. I’m planning to use the KV as a cache to avoid hitting network excessively

SSam That’s good to know, do you have an example showing json value into KV? How do I...

o7•3/27/25, 8:45 PM

if ur JSON is small enough (and since you're working with JSON) you can/should probably also insert it into the metadata https://developers.cloudflare.com/kv/api/write-key-value-pairs/#metadata

https://developers.cloudflare.com/kv/api/list-keys/#optimizing-storage-with-metadata-for-list-operations

SSam That’s good to know, do you have an example showing json value into KV? How do I...

Isaac McFadyenOP•3/27/25, 8:45 PM

The putput accepts any string, ReadableStream, or ArrayBuffer so you can just JSON.stringify it: https://developers.cloudflare.com/kv/api/write-key-value-pairs/

Sam•3/27/25, 8:47 PM

It’s Pirate weather data: https://docs.pirateweather.net/en/latest/API/#example

I hope there’s a way to cache it?

IIsaac McFadyen The `put` accepts any string, ReadableStream, or ArrayBuffer so you can just JSO...

Sam•3/27/25, 8:50 PM

I’ll try this one out tomorrow. Serialising/ Deserialising from ReadableStream should be fine

SSam I’ll try this one out tomorrow. Serialising/ Deserialising from ReadableStream s...

thomasgauvin•3/28/25, 1:36 PM

You should probably store it as a string and then read it with json. Check out the new KV examples, this is one where a list of translations are stored https://developers.cloudflare.com/kv/examples/workers-kv-to-serve-assets/#:~:text=Default%20to%20English-,const,-translations%20%3A%20%7B (could have more depth there, as much as you want)

Cloudflare Docs

Store and retrieve static assets · Cloudflare Workers KV docs

Example of how to use Workers KV to store static assets

Tthomasgauvin You should probably store it as a string and then read it with json. Check out t...

Sam•3/28/25, 2:50 PM

True, If there is no performance penalty, json.Stringifyjson.Stringify is what I'll go with . Thanks for the example, they are helpful.

Sam•3/29/25, 6:51 PM

It worked and is pretty fast. I have 2 follow-up questions:
1: I uploaded a json to KV under _preview_preview KV dashboard. How do I get it available locally? I run npx wrangler dev —remotenpx wrangler dev —remote.

Is there a way to clean the stale KV values, using some cron type job?

thomasgauvin•3/30/25, 3:57 AM

There are going to be 3 'envs' for KV. 1 is prod, 1 is preview, 1 is local. the prod is when your worker is deployed. the preview is in cloudflare when you are running npx wrangler dev --remotenpx wrangler dev --remote. the local is when your worker is running only locally npx wrangler devnpx wrangler dev. each is independent and you would need to write data in any of these dev modes to get data in there

thomasgauvin•3/30/25, 3:58 AM

you could technically make the preview id and the production id the same for development as long as you are aware that you are using your production env with npx wrangler dev --remotenpx wrangler dev --remote, this is quite dangerous which is why the preview namespace is the default

thomasgauvin•3/30/25, 3:58 AM

For stale kv values, you should look at https://developers.cloudflare.com/kv/api/write-key-value-pairs/#expiring-keys or https://developers.cloudflare.com/workers/configuration/cron-triggers/ for cron jobs

Cloudflare Docs

Cron Triggers · Cloudflare Workers docs

Enable your Worker to be executed on a schedule.

Cloudflare Docs

Write key-value pairs · Cloudflare Workers KV docs

To create a new key-value pair, or to update the value for a particular key, call the put() method of the KV binding on any KV namespace you have bound to your Worker code:

Marcel Overdijk•4/1/25, 8:19 PM

Is there a way to purge a complete namespace?
I periodically refresh my D1 database (full import) and in that use case I want to purge the full namespace that I use as cache before D1

Pedro Ribeiro•4/2/25, 3:28 AM

I'm new to the Cloudflare environment. I would like to know how can I export all the KV data from an account to a file. We need to do some migration at work.

r00bN•4/3/25, 6:17 AM

Hi, I'm having an issue deleting keys from the dashboard. Getting "remove key: 'Endpoint is unknown.'" Is this a known issue?

milan•4/4/25, 8:37 AM

has anyone tried using KV with better-auth's secondaryStorage? it seems pretty straightforward

            secondaryStorage: {
                get: async (key) => {
                    return await c.env.authKV.get(key);
                },
                set: async (key, value, ttl) => {
                    await c.env.authKV.put(key, value, { expirationTtl: ttl });
                },
                delete: async (key) => {
                    await c.env.authKV.delete(key);
                },
            },

            secondaryStorage: {
                get: async (key) => {
                    return await c.env.authKV.get(key);
                },
                set: async (key, value, ttl) => {
                    await c.env.authKV.put(key, value, { expirationTtl: ttl });
                },
                delete: async (key) => {
                    await c.env.authKV.delete(key);
                },
            },

just wondering if there are any gotchas or drawbacks I should be wary of?

Sébastien Morel•4/4/25, 11:43 PM

hello here, I can't find correct information online, is the list() function performant, or should I implement some sort of indexes inside an object instead of relying on list() ?

SSébastien Morel hello here, I can't find correct information online, is the list() function perf...

Sébastien Morel•4/4/25, 11:45 PM

usecase can be simplified as, I have a 1 customer with 3 orders, I want to get the 3 orders: should I do list(customerId)list(customerId) and then 1 getget each. or should I have a index. get(customerId-index)get(customerId-index) and then the 1 get each

Sébastien Morel•4/4/25, 11:46 PM

I believe that is important question for performances and there should be some hint in the documentation for that

Sébastien Morel•4/7/25, 5:34 PM

Good morning! nobody here?

Isaac McFadyenOP•4/7/25, 5:50 PM

List is performant, yes.

IIsaac McFadyen List is performant, yes.

Sébastien Morel•4/7/25, 5:51 PM

thanks @Isaac McFadyen

Isaac McFadyenOP•4/7/25, 5:52 PM

Also probably good to keep in mind that List can see metadata so if your data is small enough it might be worth putting into metadata so you don't need a Get for each one: https://developers.cloudflare.com/kv/api/list-keys/#optimizing-storage-with-metadata-for-list-operations

Sébastien Morel•4/7/25, 5:53 PM

yes read that but I read a blog post (old) that was stating GET was around 20-30ms and list 200ms (x10) so I got scared

SSébastien Morel yes read that but I read a blog post (old) that was stating GET was around 20-30...

Isaac McFadyenOP•4/7/25, 5:53 PM

Hmmm possible it's not cached actually (get is cached). I assumed it was but maybe not?

Isaac McFadyenOP•4/7/25, 5:53 PM

Docs don't say... if anyone else can confirm/deny then it might be a good docs addition.

Sébastien Morel•4/7/25, 5:54 PM

https://zmxv.medium.com/performance-characteristics-of-cloudflare-workers-kv-ef44ed7990b9

Sébastien Morel•4/7/25, 5:55 PM

that'd be awesome to have real value here, and answer from CF yes!

SSébastien Morel that'd be awesome to have real value here, and answer from CF yes!

leadZorr•4/7/25, 7:14 PM

That blog post is fairly old. Cold read latency for lists is lower than 10x GET latency at P99, but absolute latency values for you depend on your location as cold reads come from central stores, and also depend on how many keys you requested.

LleadZorr That blog post is fairly old. Cold read latency for lists is lower than 10x GET ...

Isaac McFadyenOP•4/7/25, 7:19 PM

Is List cached or no?

IIsaac McFadyen Is List cached or no?

leadZorr•4/7/25, 7:20 PM

It is. Each listing page is cached iirc.

Sébastien Morel•4/7/25, 7:53 PM

cool thanks guys!

Sam•4/8/25, 4:19 AM

Is there an ongoing incident with KV? Getting 500s from workers->KV

saitharun•4/9/25, 4:05 PM

Is Cloudflare KV a good option for low-latency needs, should I use it in Next.js and NestJS? We need to add it directly; we can't use the KV because it's causing latency. Is there any way to avoid this?

libor.vachal•4/30/25, 6:18 AM

Hi, I have a question about Metrics and how to interpret them. OI the image, there is read latency of our KV store. Is this correct interpretation?

P99 390ms: means that 99% of read operations are done under 390ms
P50 18ms: means that 50% of read operations are done under 18ms

usualdev•5/7/25, 8:43 PM

Anyone seeing latency issues in KV?

Uusualdev Anyone seeing latency issues in KV?

Chaika•5/7/25, 8:47 PM

not really

Chaika•5/7/25, 8:47 PM

the chart to the right of that is more interesting, how many cold reads do you have? Are you setting cacheTtl higher where you can/have a lot of infrequent keys?

CChaika not really

usualdev•5/7/25, 8:49 PM

Thanks @Chaika I'm not using cacheTtl, I will set it now and see.
this is my read status chart

Uusualdev Thanks @Chaika I'm not using cacheTtl, I will set it now and see. this is my rea...

Chaika•5/7/25, 8:50 PM

good amount of cold reads. KV only has two actual backing stores/locations, one us and one in the eu, it's then cached everywhere else. Cold reads are expensive
Raising cacheTtl at the cost of consistency can help if it fits your use, or in general aiming to hit a few frequent keys rather then many infrequent

yinxingmaiming6409•5/15/25, 7:18 AM

If you don't need workers and want to use KV, you can only use HTTP, right? The interface request limit is too low.

Yyinxingmaiming6409 If you don't need workers and want to use KV, you can only use HTTP, right? The ...

Hello, I’m Allie!•5/15/25, 7:23 AM

Yes. KV is really meant to be used with Workers. In the event you don’t want your program logic on Workers, I would still recommend using a Worker to do the actual reads/writes against KV, as it should be a lot more performant than using the default HTTP API

yinxingmaiming6409•5/15/25, 7:26 AM

But it's really difficult for workers to restrict the development language

Yyinxingmaiming6409 But it's really difficult for workers to restrict the development language

Hello, I’m Allie!•5/15/25, 1:30 PM

What do you mean?

HHello, I’m Allie!Yes. KV is really meant to be used with Workers. In the event you don’t want you...

alotabits•5/15/25, 6:12 PM

Is this because of the connection overhead of using the HTTP API? And is it mitigated for writes if you’re using bulk writes?

thomasgauvin•5/16/25, 1:45 PM

Yes, it's actually because the HTTP API includes both control plane operations (create resources in Cloudflare) and data plane operations (write, read on KV for example). We're working on removing the API rate limits entirely because KV itself does not need to be rate limited

thomasgauvin•5/16/25, 1:46 PM

So today, if you use bulk operations, you can definitely do more operations against your KV namespace than with individual operations

Tthomasgauvin Yes, it's actually because the HTTP API includes both control plane operations (...

1984 Ford Laser•5/16/25, 10:26 PM

Is the removal of the API rate limit just for the KV endpoints? Or is there a more general discussion around removing that limit altogether

Note that in contrast to JSON-oriented databases, KV just stores the bytes. You can't query on nes

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