Executive Summary
This proposal funds 16 months (September 2026 - Dec 2027) of maintenance for the open-source substrate-api-client, a Rust RPC client library for interacting with Substrate/Polkadot-based chains, with a particular focus on no_std environments such as trusted execution environments, embedded systems, and constrained devices.
The library is actively used by ecosystem teams and fills an important gap alongside other Rust clients, such as subxt by enabling lightweight, no-std-compatible chain interaction.
The requested funding covers:
- Keeping the library aligned with Polkadot/Substrate releases
- Supporting users and contributors
- Delivering small improvements
This is a continuation of previous maintenance efforts and aims to ensure that the library remains reliable, compatible, and accessible.
Why this matters to Polkadot
The Polkadot ecosystem depends on shared infrastructure libraries that many teams use. The substrate-api-client is one of these pieces of infrastructure:
- It enables programmatic interaction with Substrate-based chains via RPC
- It is especially relevant for environments where subxt is too heavy or unavailable
- It reduces duplicated effort across multiple ecosystem teams
- It helps sustain developer choice in the Rust tooling stack
This makes the library a common good: useful across the ecosystem, open source, and maintained for broad benefit rather than a single product.
Scope of work
This proposal covers maintenance work for the period:
September 2026 - Dec 2027
1. Stay up to date with the ecosystem
Polkadot SDK and related dependencies evolve quickly. To keep the library usable, we will:
- track relevant Polkadot/Substrate releases
- update dependencies when required
- adapt the client to upstream breaking changes
- replace or remove unmaintained dependencies where needed
2. Support users and contributors
Maintenance is not only code updates; it also includes direct developer support. We will:
- respond to usage questions and integration issues
- investigate bug reports
- document known issues and workarounds
- review incoming community pull requests
- help new teams onboard to the library
3. Deliver small improvements
In addition to maintenance, we plan to implement a selected set of smaller improvements and fixes.
Candidates items include:
- Add dynamic extrinsic submission (issue #731)
- WebAssembly Support for the -client feature (issue #769)
- Extrinsic V5: Add new General() creation option (issue #822)
Final prioritization may depend on urgency, compatibility requirements, and ecosystem demand.
Deliverables
By the end of the proposal period, we commit to delivering:
- continued compatibility maintenance for relevant upstream changes
- issue triage and user support throughout the support period
- implementation of small improvements within the allocated budget
- public progress reports every 3 months in the polkadot forum
- visible work tracking through GitHub issues, PRs, releases, and changelogs
Team
Supercomputing Systems AG (SCS), Zurich, Switzerland
SCS is an engineering company with approximately 140 engineers working across software, electronics, and system design. Within SCS, a dedicated blockchain team has been contributing to the Polkadot ecosystem since 2019.
In 2022–2026, the team’s primary ecosystem contribution has been the ongoing maintenance and improvement of the substrate-api-client.
GitHub contributors:
- haerdib
- niederb
- masapr
Budget
This proposal requests $38,500 in USDT. SCS bills engineering work at 185 CHF/hour.
We have decided to go for a extended period of suppport to ensure minimal administrative effort.
| Work Package | Deliverables | Costs |
|---|---|---|
| Ecosystem updates | Dependency updates, release tracking, compatibility maintenance | $18,400 |
| User support | Issue triage, user support, PR review, bug investigation | $7,300 |
| Small improvements | Implementation, code review, documentation, release notes | $12,800 |
| Total | $38,500 |
Track Record
- 2025:
- Polkassembly - Referendum #1355 (the support was extended to one year due to less frequent polkadot updates than expected)
- 2024:( No links due to limitation, but they should all be linked by the last proposal)
- Polkadot Referendum 792
- Polkadot Referendum 546
- 2023:
- Polkadot Referendum 118
- Kusama Referendum 182
- Kusama Referendum 88
- 2022:
- Kusama Referendum 26
Forum Post
We’d love to hear your feedback on our proposal so we can shape it to meet the community’s needs.