RFC: Canton Bindings — multi-language SDKs + JWT/OIDC + pre-flight profiler (active discussion on grants-discuss)

Hi everyone, sharing a heads-up on a Dev Fund RFC currently active
on grants-discuss, in case the community here would like to weigh in.

Following the Q1 2026 Developer Experience survey results that @dunebuggie
shared earlier this year, my co-founder Anirudh Singh and I (HackTour India,
https://x.com/HackTourIND) have scoped a proposal for the three runtime-layer
gaps the survey called out that no current PR addresses:

• Typed Client SDK + Code Generator for languages beyond TypeScript
  (Python, Java/Kotlin, Rust, Go)
• JWT/OIDC authentication middleware for TradFi/Hybrid teams
• Pre-flight transaction byte-size and Canton Coin cost profiler

Working name: Canton Bindings.

Deliberately complementary to Cantool (#77),
CantonTrace (#185), PartyLayer (#9), and Wallet Gateway (#109), with a
Cantool plugin in Milestone 4 so it integrates cleanly with Eric’s CLI.

Active discussion thread on grants-discuss:
https://lists.sync.global/g/grants-discuss/topic/rfc_canton_bindings/119439952

Full design doc (architecture, milestones, alignment table, risk register):

github.com/jatinsahijwani/canton-bindings

README.md

# Canton Bindings — Design Document (v0.1)

**A multi-language typed SDK, JWT/OIDC auth framework, and pre-flight transaction profiler for the Canton Network.**

Status: Draft for Canton Development Fund pre-PR review
Last updated: May 21, 2026

---

## 1. Problem

The Canton Foundation's Q1 2026 Developer Experience and Tooling Survey (41 respondents) identified three concrete, repeatedly-cited friction points that no project in the current Development Fund pipeline addresses:

1. **"Typed Client SDK & Code Generator: Developers currently spend days manually extracting hash strings from compiled files (.dar) and hardcoding them into their frontends."** Today, only `daml codegen js` ships officially. Teams building backends in Python, Java, Kotlin, Rust, or Go either hand-write gRPC clients against the Ledger API or maintain bespoke wrappers around the JSON API.

2. **"They also struggle significantly with implementing JWT authentication middleware, which is a repeated friction point for 'Hybrid' and 'TradFi' teams."** 83% of survey respondents identify as TradFi or Hybrid. These teams use enterprise identity (Keycloak, Auth0, Azure AD, Okta) and have to assemble JWT handling, signature verification, party-scoping, and token refresh from scratch in every language they ship.

3. **"Pre-Flight Resource & Cost Profiler: Developers often deploy 'blindly,' only discovering that their transactions are too large (hitting byte-size limits) or too expensive after they fail in a testnet or production environment."** No tool today gives a Canton developer a cost estimate before submission.

These three problems share a common shape: they all live in the **application runtime layer** between the dev loop (Cantool, dpm, Canton IDE) and the protocol (Splice, Canton core). That layer is currently empty.

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Would especially love input from folks in the Daml Tooling, DAR Lifecycle,
dApp Integration, and Canton APIs SIGs, and anyone building TradFi/Hybrid
apps who’s hit the JWT pain firsthand. Discussion in either venue welcome.

Thanks!
— Jatin