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November 2023

ยท 6 min read
Sebastian Nagel
Arnaud Bailly

This report summarizes the work on Hydra since October 2023. It serves as preparation for the monthly review meeting (see slides and recording), where the team updates project stakeholders on recent developments to gather their feedback on proposed plans.


This month, several items were restructured on the project roadmap:

The roadmap with features and ideas

The latest roadmap with features and ideas

Notable updatesโ€‹

  • Release of version 0.14.0 is imminent as most of the stateless chain observation #1096 feature is done and only some internal refactoring missing.

  • The user-submitted feature idea on supporting extended keys, #1141, has been refined. The purpose of this item is now clear, and although it's not currently a priority, work on it can be started.

  • Two new items were created to improve the developer experience of the Hydra build toolchain #1146. Additionally, a follow-up on things learned by hydra-poll aims to create a full end-to-end example of a two-player game in a Hydra head #1098.

  • There was already an item about reacting to main chain parameter changes on the roadmap, which included not only protocol parameter updates, but also hard-fork events. With the upcoming hard fork into Conway, the team split off the changes needed to navigate the hard fork and clarified them:

  • Substantial updates were made to the design of the next major feature Incremental decommit #1057, and work on it can be started.

  • In general, the team prepared several of these ๐Ÿ’ญ idea items and many of them will turn into ๐Ÿ’ฌ features soon.

Hydra developmentโ€‹

Issues and pull requests closed since the last report

This month, the team worked on the following:

MeshJS + Hydraโ€‹

At the beginning of month, the team attended the Cardano Summit in Dubai where they held the Hydra MasterClass workshop. There they also presented the Hydra-Poll dApp which is using MeshJS to build Hydra transactions on the frontend.

The Hydra team collaborated closely with the MeshJS team and as the outcome of this work The MeshJS team added some Hydra specific features to the MeshJS SDK. There is a nice low level API for building custom transactions which is pretty similar to what cardano-cli does.

Now you can use isHydra field which you can pass to this API which then uses another set of protocol paramters suitable for Hydra (eg. usually in Hydra we want to have zero transaction fees, reduce script execution units etc.).

Big thanks to the MeshJS team on giving much needed support. They were presenting these changes in the monthly review meeting so make sure to watch the recording.

Rendering the Hydra specificationโ€‹

Besides working on the design of incremental commits itself, the team also tidied up the way the Hydra protocol specification is written.

So far, the specification was written in LaTex and rendered to a PDF. LaTeX was a good choice because of its expressiveness on math expressions, but not so great a choice for pull requests and the entry barrier is quite high. The majority of documentation around Hydra and Mithril is written using Markdown and rendered into a webpage using a static site generator, currently Docusaurus. Most modern Markdown renderers do support LaTeX-style math nowadays, even the normal GitHub file preview.

Hence, the team experimented with using the more standard Markdown format to write the specification, but still being able to use LaTeX math and LaTeX macros (which are still heavily used in the spec). The aim is to have both, a PDF and HTML rendering.

While not yet finished, the GIF above shows the progress being made using pandoc to resolve macros, producing a PDF via xelatex and Docusaurus compatible markdown. Using powerful extensions of pandoc one can even convert TikZ, GraphViz and Mermaid into both target formats.

Community updateโ€‹

Beside the great work done by the MeshJS team towards supporting Hydra in the browser, here are some news and updates on community-led work streams related to Hydra:

  • SundaeLabs has made good progress on their offline mode PR which should hit the main branch soon,

  • TxPipe has been collaborating with IOG's creative engineering team to build Cardaminal, a command-line wallet, and demonstrated it during the monthly review meeting. Cardaminal is built in Rust, leveraging Pallas libraries, and is aimed at being a fully-fledged scriptable wallet providing users with powerful stateful transaction edition capabilities, native assets management, chain synchronisation, etc.

    The plan is to make Cardaminal compatible with Hydra - to be able to use it to interact with a head - and Mithril - using snapshots to synchronise the wallet.

  • The team behind ZK Snarks in Hydra Catalyst proposal is making good progress and should be able to give a demo at the next monthly review meeting


The monthly review meeting for November 2023 was held on 2023-11-27 via Google Meet with these slides and the recording.

The Hydra team is thankful to have again had so many great demos from the numerous projects in and around Hydra and Mithril projects - we should really schedule it to be one hour planned duration. Also, if you have not watched it already, make sure to check out the recording, the written report is merely expanding on a couple of topics but cannot render the cool demonstrations.

At first look, the demonstrated projects may appear not related - we even had a minimal command-line wallet on the show after all. But as we went on, these impulses spark discussions and it becomes clear that all of these projects are connected.

For example, the terminal-based wallet 'Cardaminal' as it was presented the first time in public this month, could itself become a Mithril client for faster synchronizing or even light-mode using the recently published Rust client library for Mithril. Furthermore, such a minimal wallet would be a great testing ground for a Hydra-aware wallet. The MeshJS integration also has further potential of Hydra specific fetcher and submitter providers.

On the other hand, we also stumbled over not-so-optimistic sentiment even in much more mature scaling solutions like the Bitcoin Lightning Network. This tweet summarizes that creating non-custodial [scalability/LN] solutions 'feel like the most thankless thing in the world'.

It is an exciting ride still, but events like this monthly review meeting with its colorful demonstrations of small steps to improve the usability and scalability of Cardano piece by piece with often unknown synergies is also empowering. This month again made us feel not 'only a tribe', but more a working group across the Cardano community .. the Cardano Scaling group!?