Tim Perry

Creator of HTTP Toolkit: powerful tools to debug, test & build with HTTP(S).

Passionate tech speaker, open-source contributor, and maintainer of Loglevel, Git‑Confirm and notes.

As of February 14th 2024, RFC 9512 formally registers application/yaml as the media type for all YAML content, and adds +yaml as a standard structured suffix for all YAML-based more specific media types. With this registration, it's now included in the official media types list maintained by the IANA. Media types like this (also known as the MIME t...
The X-Forwarded-For (XFF) HTTP header provides crucial insight into the origin of web requests. The header works as a mechanism for conveying the original source IP addresses of clients, and not just across one hop, but through chains of multiple intermediaries. This list of IPv4 and IPv6 addresses is helpful to understand where requests have reall...
Idempotency is when doing an operation multiple times is guaranteed to have the same effect as doing it just once. When working with APIs this is exceptionally helpful on slow or unreliable internet connections, or when dealing with particularly sensitive actions such as payments, because it makes retrying operations safe and reliable. This is why ...
It's hard to work on APIs without hearing about OpenAPI. OpenAPI is an API description format, which is essentially metadata that describes an HTTP API: where it lives, how it works, what data is available, and how it's authenticated. Additional keywords can be used to provide all sorts of validation information, adding a type system to what would ...
Everything crashes. Sometimes things crash when they're running inside a Docker container though, and then all of a sudden it can get much more difficult to work out why, or what the hell to do next. Docker's great, but it's an extra layer of complexity that means you can't always easily poke your app up close any more, and that can really hinder d...
A couple of weeks ago I published a post about changes in Android 14 that fundamentally break existing approaches to installing system-level CA certificates, even with root access. This has triggered some fascinating discussion! I highly recommend a skim through the debate on Mastodon and Hacker News. Since that was posted, quite a few people have ...
Update: This post sparked a lot of excellent discussion and debate on workarounds, and there are now multple working solutions to allow certificate injection on Android 14, despite the restrictions discussed here. See the update post for more details. When Android was initially announced in 2007 by the Open Handset Alliance (headed by Google) their...
There's been a lot of concern recently about the Web Environment Integrity proposal, developed by a selection of authors from Google, and apparently being prototyped in Chromium. There's good reason for anger here (though I'm not sure yelling at people on GitHub is necessarily the best outlet). This proposal amounts to attestation on the web, limit...
Caching is hard. Unfortunately though, caching is quite important. Hosted caching & CDNs offer incredible powers that can provide amazing performance boosts, cost savings & downtime protection, essential for most modern sites with any serious volume of users. Unfortunately, while there are strict standards for how caching is supposed to work with H...
This week, at long last, GitHub announced granular access tokens for npm. This is a big deal! It's great for security generally, but also particularly useful if you maintain any npm packages, as it removes the main downside of automating npm publishing, by allowing you to give CI jobs only a very limited token instead of full 2FA-free access to you...
As you may have seen, Docker Hub made a dramatic shift in policy this week, and effectively gave a 30 day eviction notice to almost all community-run images. They've now made an apology to 'clarify' a few details, and helpfully take some of the hard edges off, but this still highlights a big problem. Fortunately, there are solutions. As initially d...
HTTP Toolkit has been selected to receive another round of open-source funding from the EU! This aims to improve interception of HTTPS traffic from mobile apps, making it easier for both security/privacy researchers and normal technical users to inspect & manipulate the data that any app they use sends & receives. This funding will directly support...
HTTP is important on the web, but as other alternative protocols grow popular in networked applications, it's often important to be able to capture, debug and mock those too. I've been working on expanding HTTP Toolkit's support for this over the past year (as one part of a project funded by EU Horizon's Next Generation Internet initiative), to ext...
The world of decentralized web applications is an exciting place that has exploded in recent years, with technologies such as IPFS and Ethereum opening up possibilities for a peer-to-peer web - creating applications that live outside the traditional client/server model, where users to interact and control their own data directly. At the same time, ...
Further updates required very significantly more relearning of perl than I expected (to read some remarkably c...
Further updates required very significantly more relearning of perl than I expected (to read some remarkably c...
Just a casual PR changing the logic used by all modern OpenSSL TLS connections everywhere, no biggie 😬 https:/...
Just a casual PR changing the logic used by all modern OpenSSL TLS connections everywhere, no biggie 😬 https:/...
Use empty renegotiate extension instead of SCSV for TLS > 1.0
(Looking at https://github.com/openssl/openssl/issues/19220 specifically - help from anybody else interested i...
(Looking at https://github.com/openssl/openssl/issues/19220 specifically - help from anybody else interested i...
This is definitely going to end well
This is definitely going to end well
I do really enjoy the way some user feedback (https://github.com/httptoolkit/httptoolkit/issues/579) leads me ...
I do really enjoy the way some user feedback (https://github.com/httptoolkit/httptoolkit/issues/579) leads me ...
Testing out the HTTP Toolkit app on a teeny weeny screens, and it turns out Android Studio has a Nexus One mod...
Testing out the HTTP Toolkit app on a teeny weeny screens, and it turns out Android Studio has a Nexus One mod...
Is this open source? There's no license
Comment by Tim Perry on HTTP Toolkit interception with Android emulator interfering: app not working when enabled
How long have you had HTTP Toolkit open? If you haven't completely restarted the app in many days, it's possib...
Also gives me two small very accessible Docker hosts that I can run more services for myself on top!So far loo...
Also gives me two small very accessible Docker hosts that I can run more services for myself on top!So far loo...
Costs, for example.2x NAS (one at home + one in the office, for redundancy) syncing together costs <€500 as...
Costs, for example.2x NAS (one at home + one in the office, for redundancy) syncing together costs <€500 as...
Spent a chunk of the weekend looking at new backup solutions. Currently using mega.io (documents etc) + google...
Spent a chunk of the weekend looking at new backup solutions. Currently using mega.io (documents etc) + google...
Mockbin.com/har has stopped working
Another day, another PR to the minutiae of Node.js's internal network stream handling: https://github.com/...
Another day, another PR to the minutiae of Node.js's internal network stream handling: https://github.com/...
Fix h2-over-h2 connection proxying
AI sings the MIT license: https://app.suno.ai/song/da6d4a83-1001-4694-8c28-648a6e8bad0a/
AI sings the MIT license: https://app.suno.ai/song/da6d4a83-1001-4694-8c28-648a6e8bad0a/
Answer by Tim Perry for How to ignore timeouts in ab (apache bench)?
The -r option says "Don't exit on socket receive errors" (see docs here). This disables the 'exit on first fai...
Cannot CONNECT http2-over-http2 in Node 20.12.0
I'm setting up a new network testing service with debug endpoints for lots of protocols (a la httpbin.org ...
I'm setting up a new network testing service with debug endpoints for lots of protocols (a la httpbin.org ...
Extremely excited about the JS Signals proposal: https://github.com/proposal-signals/proposal-signalsI've ...
Extremely excited about the JS Signals proposal: https://github.com/proposal-signals/proposal-signalsI've ...
Answer by Tim Perry for Charles Proxy vs Developer Console vs Browserstack
Debugging proxies like Charles Proxy, HTTP Toolkit and Fiddler all have a few features that browser developer ...
New repo: httptoolkit/test
Opt-out request for pimterry
Require(esm) is coming to node!!!This Node.js PR is going to personally save me (and anybody doing a lot of No...
Require(esm) is coming to node!!!This Node.js PR is going to personally save me (and anybody doing a lot of No...