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#745Needs Champion Pull Request2.9M CC requested

HALO: High-Availability Ledger API Overlay for Multi-Hosted Applications

kevmuko29-08-2026Last activity 7d ago
party-portability-data-resilienceneeds-champion

Development Fund Proposal Submission

Proposal file:
/proposals/2026-08-K2FLabs-halo-ledger-api-overlay.md

Applicant

Organization:
K2F Labs

Author / Primary Contact:
Kevin Ko, kko@k2flabs.com

Champion:
Needs Champion

Proposal Classification

Proposal Type:

  • RFP-aligned proposal
  • Individual initiative

RFP / Roadmap Area:
RFP 4, Application-level resilience and party-level Highly Available failover (Protocol, Infrastructure, Scalability & Resilience). Secondary RFP 23, Validator and Shared Infrastructure Security and Resilience.

Label:
party-portability-data-resilience

Funding & Timeline

Total Funding Request:
2,850,000 CC (engineering 1,850,000 CC, adoption up to 1,000,000 CC)

Project Duration:
7 months engineering, adoption window 12 months from Milestone 3 acceptance

Maximum Amount:
N/A

Maximum Duration:
N/A

Summary

Co-validation lets a party be hosted on several validators, but an application still submits through one participant, and Canton's documentation states that an application cannot transparently fail over between participants because deduplication state is not shared. HALO is an open-source sidecar (Rust, Apache-2.0) that presents the unchanged Ledger API, routes each submission to a healthy host of the party, fails over to another host after a host is lost without duplicating a transaction, and adds traffic priority lanes, optional consumption-driven top-up and per-host observability. It makes co-validation cover submission as well as confirmation, for every application in every language, with no changes to Canton, Splice or any SDK.

Submission Checklist

  • Full proposal file is included in this PR
  • Organization and primary contact identified
  • Champion identified or Needs Champion selected
  • RFP / roadmap alignment identified, if applicable
  • Total funding request provided
  • Project duration provided
  • Proposal is within any RFP maximum amount
  • Proposal is within any RFP maximum duration
  • Milestones and milestone funding are defined in the proposal
  • Acceptance criteria are based on ecosystem value
  • Architectural alignment is addressed
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