Deposit Networks
A category case study on the API-first rewiring of wholesale deposit liquidity
Business Context
Public research artifact. Written as an engineer's honest appraisal of an emerging fintech infrastructure category — what makes the wedge real, what the structural risks look like, and how I'd build in it if I were on a founding team.
Overview
A public research case study on the reciprocal deposit and wholesale liquidity category — the $2.3T market still running on phone calls and spreadsheets that a handful of API-first startups are now quietly replatforming.
The write-up covers the category's customers and their morning-of pain (EGRRCPA headroom, coverage ceilings, settlement breaks), the incumbent and challenger landscape, the structural tailwinds that opened the wedge post-SVB, the real headwinds any winner has to solve (integration politics, network bootstrapping, regulated-utility trust), and an opinionated take on how I'd architect the platform — including a static concept UI, system architecture diagrams, and an OpenAPI specification for the institution-facing surface.
Positioned as an outsider-engineer's research artifact, not a product pitch or a grade of any single company. It was written because the problem space is genuinely one of the most interesting regulated-infrastructure wedges in fintech right now.
Key Contributions
- Category map of reciprocal deposit and wholesale liquidity infrastructure — incumbents, challengers, and the wedge post-SVB
- Concept UI exploring the three operator personas a platform in this space has to serve: treasury, controller, and network admin
- System architecture decomposing a regulated network platform into services with clear trust boundaries and failure modes
- OpenAPI 3.1 specification for the institution-facing API surface — mTLS, idempotency, audit, and coverage-aware order placement
- Append-only double-entry ledger data model with reconciliation break handling as a first-class concept
- EGRRCPA headroom and insurance coverage modeled as the KPIs customer operators actually live inside
- Opinionated take on what a winner in this category has to solve to reach IPO-velocity — integration throughput, trust posture, and economic model design