Taking hyper-curl further

Thanks to funding by ISRG (via Google), we merged the hyper powered HTTP back-end into curl earlier this year as an alternative HTTP/1 and HTTP/2 implementation. Previously, there was only one way to do HTTP/1 and 2 in curl.


Core libcurl functionality can be powered by optional and alternative backends in a way that doesn’t change the API or directly affect the application. This is done by featuring internal APIs that can be implemented by independent components. See the illustration below (click for higher resolution).

This is a slide from Daniel’s libcurl under the hood presentation.

curl 7.75.0 became the first curl release that could be built with hyper. The support for it was labeled “experimental” as while most of all common and basic use cases were supported, we still couldn’t run the full test suite when built with it and some edge cases even crashed.

We’ve subsequently fixed a few of the worst flaws so the Hyper powered curl has gradually and slowly improved since then.

Going further

Our best friends at ISRG has now once again put up funding and I’ll spend more work hours on making sure that more (preferably all) tests can run with hyper.

I’ve already started. Right now I’m sitting and staring at test case 154 which is doing a HTTP PUT using Digest authentication and an Expect: 100-continue header and this test case currently doesn’t work correctly when built to use Hyper. I’ll report back in a few weeks and let you know how it goes – and then I don’t mean with just test 154!

Consider yourself invited to join the #curl IRC channel and chat if you want live reports or want to help out!


You too can fund me to do curl work. Get in touch!

Giving away an insane amount of curl stickers

Part 1. The beginning. (There will be at least one more part later on following up the progress.)

On May 18, 2021 I posted a tweet that I was giving away curl stickers for free to anyone who’d submit their address to me. It looked like this:

Everyone once in a while when I post a photo that involves curl stickers, a few people ask me where they can get hold of such. I figured it was about time I properly offered “the world” some. I expected maybe 50 or a 100 people would take me up on this offer.

The response was totally overwhelming and immediate. Within the first hour 270 persons had already requested stickers. After 24 hours when I closed the form again, 1003 addresses had been submitted. To countries all around the globe. Quite the avalanche.

Assessing the damage

This level of interest put up some challenges I hadn’t planned for. Do I have stickers enough? Now suddenly doing 3 or 5 stickers per parcel will have a major impact. Getting envelops and addresses onto them for a thousand deliveries is quite a job! Not to mention the cost. A “standard mail” to outside Sweden using the regular postal service is 24 SEK. That’s ~2.9 USD. Per parcel. Add the extra expenses and we’re at an adventure north of 3,000 USD.

For this kind of volume, I can get a better rate by registering as a “company customer”. It adds some extra work for me though but I haven’t worked out the details around this yet.

Let me be clear: I already from the beginning planned to ask for reimbursement from the curl fund for my expenses for this stunt. I would mostly add my work on this for free. Maybe “hire” my daughter for an extra set of hands.


During the time the form was up, we also received 51 donations to Open Collective (as the form mentioned that, and I also mentioned it on Twitter several times). The donated total was 943 USD. The average donation was 18 USD, the largest ones (2) were at 100 USD and the smallest was 2 USD.

Of course some donations might not be related to this and some donations may very well arrive after this form was closed again.

Cleaning up

If I had thought this through better at the beginning, I would not have asked for the address using a free text field like this. People clearly don’t have the same idea of how to do this as I do.

I had to manually go through the addresses to insert newlines, add country names and remove obviously broken addresses. For example, a common pattern was addresses added with only a 6-8 digit number? I think over 20 addresses were specified like that!

Clearly there’s a lesson to be had there.

After removing obviously bad and broken addresses there were 978 addresses left.


I got postal addresses to 65 different countries. A surprisingly diverse collection I think. The top 10 countries were:

The Netherlands24

Countries that were only entered once: Dubai, Iran, Japan, Latvia, Morocco, Nicaragua, Philippines, Romania, Serbia, Thailand, Tunisia, UAE, Ukraine, Uruguay, Zimbabwe

Figuring out the process

While I explicitly said I wouldn’t guarantee that everyone gets stickers, I want to do my best in delivering a few to every single one who asked for them.


I have the best community. Without me saying a word or asking for it, several people raised their hands and volunteered to offload the sending to their countries. I could send one big batch to them and they redistribute within their countries. They would handle US, Czechia, Denmark and Switzerland for me.

But why stop at those four? In my next step I put up a public plea for more volunteers on Twitter and man, I got myself a busy evening and after a few hours I had friends signed up from over 20 countries offering to redistributed stickers within the respective countries. This way, we share the expenses and the work load, and mailing out many smaller parcels within countries is also a lot cheaper than me sending them all individually from Sweden.

After a lot of communications I had an army of helpers lined up.

28 distributors will help me do 724 sticker deliveries to 24 countries. Leaving me to do just the remaining 282 packages to the other 41 countries.

Stickers inventory

I’ve offered “a few” stickers and I decided that means 4.

978 * 4 = 3912

Plus I want to add 10 extra stickers to each distributor, and there are 28 distributors.

3912 + 28 * 10 = 4192

Do I have 4200 curl stickers? I emptied my sticker drawer and put them all on the table and took this photo. All of these curl stickers you see on the photo have been donated to us/me by sponsors. Most of the from Sticker Mule.

I think I might be a little “thin”. Luckily, I have friends that can help me stock up

(There are some Haxx and wolfSSL stickers on the photo as well, because I figured I should spice up some packages with some of those as well.)


The stickers still haven’t shipped from my place but the plan is to get the bulk of them shipped from me within days. Stay tuned. There will of course be more delays on the route to their destinations, but rest assured that we intend to deliver to all who asked for them!

Will I give away more curl stickers?

Not now, and I don’t have any plans on doing this stunt again very soon. It was already way more than I expected. More attention, more desire and definitely a lot more work!

But at the first opportunity where you meet me physically I will of course give away stickers.

Buy curl stickers?

I’ve started looking into offering stickers for purchase but I’m not ready to make anything public or official yet. Stay tuned and I promise you’ll learn and be told when the sticker shop opens.

If it happens, the stickers will not be very cheap but you should rather see each such sticker as a mini-sponsorship.

Follow up

Stay tuned. I will be back with updates. See Part 2.