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, ...
Comment by Tim Perry on Install CA Certificate on android emulator
@AndyBoy that means your app is either using certificate pinning to actively reject CAs, or you've installed a...
Comment by Tim Perry on stop Charles from tracking my app's requests without SSL Pinning in iOS
I mean it might raise difficult a tiny bit, but by maybe 10 minutes of effort (if you don't know what you're d...
The thing that surprises me most about the whole Crowdstrike mess is that so much key infrastructure apparentl...
The thing that surprises me most about the whole Crowdstrike mess is that so much key infrastructure apparentl...
Disable jailbreak detection
Zstd-codec crashes in Node v20 and v22 due to deprecations
Personally though, as both a package maintainer & consumer, I would really love to see the ecosystem incre...
Personally though, as both a package maintainer & consumer, I would really love to see the ecosystem incre...
Ofc if you're an maintainer and you just really want to write in ESM exclusively, sure it's your packa...
Ofc if you're an maintainer and you just really want to write in ESM exclusively, sure it's your packa...
This is https://npmjs.com/package/stringify-object, for reference.It's really depressing really - backward...
This is https://npmjs.com/package/stringify-object, for reference.It's really depressing really - backward...
Guess which version switched to ESM-only? #javascript #esm
Guess which version switched to ESM-only? #javascript #esm
Httpsnippet uses ajv but doesn't actually depend on it
😃 Found it!It turns out that some of the Sentry team are work on exactly this literally right now: https://git...
😃 Found it!It turns out that some of the Sentry team are work on exactly this literally right now: https://git...
Great idea
And following the same model as 1% For The Planet or the B-Corp certification, the certifying org would charge...
And following the same model as 1% For The Planet or the B-Corp certification, the certifying org would charge...
Acts as a nice dev marketing & recruitment boost, helps your relationship with the FOSS devs you depend on...
Acts as a nice dev marketing & recruitment boost, helps your relationship with the FOSS devs you depend on...
https://www.onepercentfortheplanet.org/ is cool.Does something similar exist for open-source donations? I.e. a...
https://www.onepercentfortheplanet.org/ is cool.Does something similar exist for open-source donations? I.e. a...
Ah fun, new supply chain attack just dropped: https://sansec.io/research/polyfill-supply-chain-attack> this...
Ah fun, new supply chain attack just dropped: https://sansec.io/research/polyfill-supply-chain-attack> this...
Answer by Tim Perry for Is there a way to get the device name using adb? For example, if the device name is John Doe's Nexus, how to get the name using a command?
It's not totally clear, but you may be looking for the user-editable 'device name' (in the settings, under 'Ab...
Answer by Tim Perry for stop Charles from tracking my app's requests without SSL Pinning in iOS
No - there's no way to do this, and actually even SSL pinning cannot guarantee this. More generally: it is imp...
A new testimonial for httptoolkit.com that I'm very very pleased with indeed.Kind words notably coming fro...
A new testimonial for httptoolkit.com that I'm very very pleased with indeed.Kind words notably coming fro...
Answer by Tim Perry for local docker interception, HTTP, doesn't intercept or CORS
HTTP Toolkit (and all similar tools) act as HTTP proxies. That means that to intercept traffic using them, you...
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Spent some of the weekend playing with Arduinos + Home Assistant (@homeassistant) to keep a better eye on my p...
Spent some of the weekend playing with Arduinos + Home Assistant (@homeassistant) to keep a better eye on my p...
Comment by Tim Perry on How to correctly trace all outboud Node.js request on server apps with Express
You can intercept, fully view & manually modify all traffic from all sources in the free version. If you find ...
Answer by Tim Perry for How to correctly trace all outboud Node.js request on server apps with Express
Node.js ignores proxy settings by default, unlike many languages (see https://github.com/nodejs/node/issues/83...
A user has triggered a minor meltdown by emailing a template GDPR right to be forgotten email to me and the su...
A user has triggered a minor meltdown by emailing a template GDPR right to be forgotten email to me and the su...