Show HN: API Parrot – Automatically Reverse Engineer HTTP APIs

[pvarghav]

When automating business processes at work, I found it difficult and time-consuming to reverse engineer business systems' APIs. I often had to manually reverse engineer APIs using developer tools or settle for less optimal technologies such as Robotic Process Automation (RPA).

Often, the issue is that it can be hard to resolve all the cookies, access tokens, and other elements required to successfully execute the requests. Manually trying to resolve these dependencies using developer tools is especially challenging with multiple requests where data is stored in JavaScript objects or HTML elements.

To try to solve this issue, I built a tool called API Parrot that automatically identifies the data correlations between requests and builds a graphical representation of the flow to give users a better understanding. To streamline the process, I also included functionality to record requests, define your own inputs and outputs, and export the entire flow—or parts of it—as JavaScript code.

The application is Electron-based and currently compiled for Windows and Linux. Please try it out and give feedback!

Online Tutorial: A simple example of reverse engineering the USPS API is available at https://docs.apiparrot.com/docs/category/tutorial---reverse-...

[brushfoot]

Impressive project. I was curious how it discovers data relationships and was going to check the repo, but it looks like there's no code, only issues and releases. Is that right?

Which leads me to...

- Is this closed source?

- Does it cost money?

- How does it discover data relationships?

[pvarghav]

Thanks for your interest!

- Is this closed source?

Currently, the code is not open source, but I might open-source parts of it in the future.

- Does it cost money?

The software is free to use. If there is demand, I might create a "pro" version for businesses in the future. However, I intend to always have a free version available for individuals.

- How does it discover data relationships?

I've discussed how it discovers data relationships in the documentation here: https://docs.apiparrot.com/docs/tutorial-extras/exchange-mod....

In short, the tool breaks down the data in the requests and responses into smaller parts by identifying their formats. For example, `["foo", "bar"]` would be recognized as a JSON array and broken down into the elements `"foo"` and `"bar"`. By applying this method recursively, you build a tree-like structure of the data.

If an exact match is found between data in a response from a previous request and data in a subsequent request, a correlation is detected.

Please feel free to ask if you have any more questions!

[skeptrune]

It's entertaining that Github has become such a common place to find information that even closed source projects put something up there

[rynn]

How does it compare to mitmmitmproxy2swagger?

https://github.com/alufers/mitmproxy2swagger

[faizshah]

This might be more useful than the OP. This thing lets you translate HAR to Swagger…

My usual process is Dev tools -> Copy as CURL -> delete unnecessary headers -> translates to requests in python (these days I just use ChatGPT) -> wrap in python sdk for managing auth etc.

The OP’s correlation features are really nice though.

[1a527dd5]

The first and immediate difference for me is the ability to recall the name. I can recall Postman/Insomina fine, and now for API Parrot. I'm never going to be able to recall mitmproxy2swagger.

Unfortunately, names matter.

[notcrazylol]

Probably a dumb question but if my web app uses graphql, how would I go about with the swagger generation?(since its just one endpoint)

Thank you for sharing this though, I was looking for a tool like this :)

[setheron]

Very sad half the comments are asking for MacOS app. The rise of development on MacOS for server development when the final target is Linux will cause long term harm to the newer generation of engineers

[gempir]

And the unreasonable hostility towards macOS will have zero affect because in the end the best product wins.

Did the rise of Windows cause long term harm to past generation of engineers? I doubt it since now Windows, which had a gigantic market share, still was forced to implement Linux "compatibility" for developers.

There are three popular operating systems for the modern developer and it's not unreasonable to ask for a build for all of them when presenting a project to a developer focused community.

[victorbjorklund]

Why? I mostly code on Mac and deploy on Linux (or FreeBSD). Never really encountered a situation where programming a web app on Mac has caused issues when deploying to the server.

[criddell]

Or maybe some of the newer generation will take time to update Linux to be more competitive with macOS for developers. Could be a long term win for Linux fans.

[cdaringe]

Not sad at all! Mac has excellent hardware, excellent reliability, excellent day to day performance. Im not a fanboy, but it won for (IMHO) clear and obvious reasons. Of course folks want a mac app. No comment on the “harm” bit.

[forty]

I agree, people don't realize the value of not depending on a single company to do their work. We can see this problem even more with LLM code generators.

[yoavmmn]

Nowadays everything runs on docker anyway

[Merad]

Really? In the modern .Net world (originally .Net Core) it's very common for devs to use Windows machines to write code whose CI pipelines and deployed environments are all Linux. I've seen a handful of issues with things like path separators and file system case sensitivity, but we're talking about 3 or 4 minor problems in 6-7 years that I've been using it.

[chuckadams]

How about a real-world example of the harm you're clutching your pearls over?

Besides, most devs doing web development on Macs are also using Docker, which is always Linux.

[dangoodmanUT]

conjecture?

[rafram]

Most people scraping sites aren’t writing anything low-level enough to care about the particular flavor of Unix-like OS it runs on.

[255kb]

Nice project!

Just so you know, there is an app called Traffic Parrot (https://trafficparrot.com/). They operate on the same market, so they may not like the name you chose.

[yawndex]

Any current plans for a macOS release?

[pvarghav]

Yes, I plan to release a macOS version of API Parrot. Unfortunately, I currently don't own a Mac, and since building macOS applications requires one, this has delayed the release. I'm actively exploring solutions, such as accessing a Mac environment remotely or acquiring the necessary hardware.

[pvarghav]

The macOS version is now available for download at https://apiparrot.com/#download

Please note that since the app isn't code-signed yet, you'll need to remove the quarantine attribute to run it. I've updated the documentation with instructions on how to do this: https://docs.apiparrot.com/docs/getting-started/download-and...

Let me know if you have any questions or run into any issues!

[MK2k]

Try a Hackintosh, e.g. as a virtual machine on your Windows or Linux host.

[sumanyusharma]

How is this different from Integuru? They posted a few weeks back here: https://news.ycombinator.com/item?id=41983409

[shawnshivdat]

^

[martinkostov]

I'm curious too

[sebmellen]

This is incredible. We’ve spent ages and ages figuring out the weird internals of certain legacy systems that we’ve ended up having to use bots or RPA to integrate with. If you can polish this into a true product, we would pay for it!

Any chance of a Mac version?

[pvarghav]

Thanks! I'm glad you like the idea—it sounds like you've had the same struggles I've been through.

Good news: the Mac version is now available to download at https://apiparrot.com/#download.

Let me know if you have any feedback!

[colesantiago]

This is the easy part.

One of the issues with these tools is that more and more websites now employ multiple aggressive CAPTCHAs, fingerprints, device check, etc, rendering tools like API Parrot almost useless.

[jknutson]

Love the idea. I’m always finding myself writing little user scripts / browser extensions to extend websites I use all the time, and trying to use an API I found in the devtools network requests page always gets annoying when I have to try and do anything beyond replicating the exact input/output I found in the original request.

Haven’t fully looked through the features/docs, so forgive me if my question is answered in there, but what does support look like for:

- Exporting to Swagger/OpenAPI Spec

- Exporting to generated SDK (I know some tools exist that can generate SDKs from OpenAPI/Swagger, so maybe some of these tools have licenses that are compatible with your product?)

- Support for URL path variables (e.g. `/users/{user_id}`)

- Support for URL query parameters (and filtering for common “noise” parameters, e.g. Google analytics)

- Support for non-JSON input/output (e.g. an endpoint that accepts multipart form data)

Awesome idea though. I’m definitely going to try this out. Beautiful UI and website too. I’m stoked to play around with this!

[pvarghav]

I'm glad you like the idea! Let me answer your questions one by one:

- Exporting to Swagger/OpenAPI Spec: Currently, exporting to Swagger/OpenAPI isn't supported, but it's on my to-do list to look into. Right now, JavaScript code is the only export format.

- Exporting to a Generated SDK: Same as above. I'm considering integrating tools that can generate SDKs from OpenAPI/Swagger specs, so this might be included in a future update.

- Support for URL Path Variables (e.g., `/users/{user_id}`): Yes, API Parrot supports URL path variables!

- Support for URL Query Parameters (and filtering out common "noise" parameters like Google Analytics): Yes, API Parrot supports URL query parameters, and there are measures in place to filter out the noise.

- Support for Non-JSON Input/Output (e.g., endpoints that accept multipart form data): There is support for non-JSON input/output formats, but multipart form data isn't supported at this time. You can find all the supported data types on this page: https://docs.apiparrot.com/docs/tutorial-extras/exchange-mod...

Thanks again for your support! I'm excited for you to try it out, and I'd love to hear your feedback after you've had a chance to play around with it.

[speakspokespok]

I've just gone through the "Docs" section and I appreciate how it covers the intended workflow and use cases. I'm on Debian/Intel and other than the need to install Chrome I only had a few small issues.

++ A self contained appImage is a good way to go, but where do you put it? A default install location should be added for those used to an `apt install`.

I went `sudo wget $URL -C /usr/local/bin/` and `chmod +x $appimage`. This worked fine until Collection creation when some internal state change smacked into my root owned file permissions. I `chmod 777` it and restarted the app, no more issue. It's my machine and I can chmod how I want but I think doc clarity would help those unfamiliar with appimage.

++ Renaming projects, collections, etc is cumbersome. For example, when clicking the 'New Project" pencil a change name window opens with several steps needed then to rename the project. That single click could combine opening the window, that window grabbing focus, with the cursor in a blank form window, followed by 'Enter'.

++ Ability to toggle showing the Properties column. On a 14" hi rez laptop, the screen is crowded. And resize Project width.

++ The default flow view size is too small.

I hope that's helpful. A small number of UI tweaks and it's already at "Don't F*** With It!" stage. The issues above are small and don't take away from how great and EXCITED I was going through the tutorial. I went through the entire docs and the tutorial and I think it's a fine program. Your layout of the DOM response is also really nice!

[pvarghav]

I'm glad to hear that you like the product and found the tutorial helpful. I've updated the documentation to include instructions for installing the AppImage—thanks for bringing that to my attention.

I really appreciate your detailed feedback on the UI and usability. I'll definitely take your suggestions into consideration and work on implementing them in future versions.

Thanks again for taking the time to share your thoughts!

[davide_v]

Nice, I was looking for something like this. I tried it on Ubuntu but after clicking Capture requests > Launch Chrome, nothing happens.

[chompin]

Same issue, would prefer the option to use any browser also. Chrome is not my cup of tea

[7357]

Looks like it wants to run chrome using `start chrome` which is AFAIK a Windows-only command.

[pvarghav]

Thank you for pointing this out. I've addressed the issue, and it should now be fixed in version 0.2.1, which is available for download on the website. Please update to the latest version, and let me know if you encounter any more problems.

[ashenke]

Yep same problem

[pvarghav]

Update: The macOS version is now available for download at https://apiparrot.com/#download

Please note that since the app isn't code-signed yet, you'll need to remove the quarantine attribute to run it. I've updated the documentation with instructions on how to do this: https://docs.apiparrot.com/docs/getting-started/download-and...

Let me know if you have any questions or run into any issues!

[YaBa]

Interesting but... The first website I've tried it (which I'm currently working on due to a change of platform) couldn't find anything other than the main request, and I know for sure there is a POST reguest to the API to get some data (I had a scrapper working, website changed, had to re-do the scrapper again).

I've checked the tutorial, seems that I'm not missing any step, the software simple cannot capture anything if the request is made on the main page, seems to work fine with forms, buttons and "manual" actions.

I can DM you the website plus the expected request that is made, visible with any browser internal debugging tools.

[teichman]

Integru has been really great for us. Curious how you think about differentiation?

[yellow_lead]

Hi, it seems youve spelled reverse wrong

> API Parrot is the tool specifically designed to reverese engineer the HTTP APIs of any website.

[pvarghav]

Thanks for pointing this out!

It should now be fixed.

[devops000]

Feedback: add a newsletter form to get notification when you will release the MacOSX version

[pvarghav]

Thank you for your suggestion!

I've added a newsletter sign-up form at the bottom of the webpage: https://apiparrot.com/#newsletter

Feel free to subscribe to receive notifications when we release the MacOSX version.

[toomuchtodo]

+1, ready to buy

[spacecadet404]

Nice project, I was able to use it to map out some parts of a vendor's API that's been giving me grief today. I'm pretty amateur and this was really intuitive. Happily putting this in my toolbox.

[arshxyz]

Interesting project, I've often looked for something like this but haven't found anything that does the job. I'm on a mac and can't wait to try this out. Can I ask what you're using adblock-rs for?

[pvarghav]

Glad you like the project! I'm working on getting the macOS version built and released as soon as possible. If you'd like to be notified when it's ready, you can sign up for the newsletter here: https://apiparrot.com/#newsletter.

As for adblock-rs, I'm using it to detect and automatically disable requests related to ads and other unnecessary stuff. This helps cut down on noise and saves some time for developers.

[1a527dd5]

This is pretty cool, I ran it against one of a largest customer sites and it was very interesting to see how the page all interconnects. I'm pretty sure it can be used to spot architecture/performance problems.

[sidgarimella]

Love this. I’ve worked on a few projects in RPA prior and I’m losing faith in selectors. I think either direct data access like this or AI based CV are the automation arms of the future.

[Sytten]

Lots of interesting ideas, a lot of the same methodology is used by bug bounty hunters/pentesters. It gives me some perspective to build something in my tool.

[tveyben]

I’m not able to read what the product actually does - I keep getting distracted by the ‘snake’ animation surrounding the content .. not sure what the purpose is ;-)

[remoquete]

Looks very interesting. Does it produce an OpenAPI file? That'd help immensely in documenting APIs that lack specifications.

[MK2k]

Nice tool! I tested it against imdb.com with its large graphql responses and after a few requests API Parrot crashed.

[gtirloni]

Is there a ToS/License somewhere?

[pkkkzip]

interesting but not sure what the value add here is, it gives you a graph flow of all the API requests being made? and then the goal is to replay them?

aren't there github libraries that do this already?

[sumedh]

> aren't there github libraries that do this already?

which ones?

[user3939382]

This has been built in to postman for years

[sumedh]

Can you please share a doc link?

[ozim]

If only there would be something with schema like XML that people would use for the APIs ;) You could generate diagrams from WSDL and even generate client code from that.

There is also bunch of JSON schema stuff nowadays.

But yeah for a lot of people schema of API contracts feels like too much work and too much hassle.

JSON serialization doesn’t throw errors for new properties quickly added on sending side and receiving side can ignore stuff - well as long as API semantics allow but that’s generally going to be a hassle always even with LLMs somehow autofixing your „schema”.

[m00dy]

can it reverse websocket-protocols ? If so, how does it do binary decoding etc ?

[pvarghav]

Currently only HTTP requests are supported. I might add support for websockets later, however that is a harder problem to solve due to the binary encoding etc.

[moon82]

looks amazing! thanks for sharing, will give it a shot in a short while. Btw, how do you keep yourself motivated on working on free projects? Obviosly it takes a lot of effort and no one is paying for that.

[pvarghav]

Thank you!

Working on this side project has been both fun and rewarding. I've learned a lot throughout the process, which keeps me motivated even without immediate financial gain. I have plenty of ideas on how to improve the software in various ways. Some of these enhancements could become part of a "pro" version tailored for businesses. My long-term ambition is to turn this into a full-fledged product, which would enable me to dedicate more time to its development.

[enricotal]

Fantastic Tool ... Mac version is paramount

[victor106]

Looks great, but no Mac app?

[woleium]

I am getting bit sick of this triplechecker spam.

[vhayda]

Nice! It needs some refinement and a macOS version.

[tommiegannert]

Could you give some examples of what refinement you think it needs?