InterposeInvest

Platform & Architecture

The front end, engineered to sit on top.

Interpose never takes custody and never connects to your custodian directly. It overlays both front ends — wealth management and self-directed — through a single gateway, event-sourced, API-first, and auditable end to end.

API-FirstEvent-SourcedBaaS-Gateway ModelBring-Your-Own CustodyCloudEvents 1.0

Design Principles

Engineered like infrastructure, not an app.

API-first

Every capability is a REST endpoint and a WebSocket stream before any UI exists. OpenAPI 3.1 is the source of truth — generate a client in any language.

Event-sourced

Positions are always derived from an immutable transaction ledger — never overwritten. Every state change emits a CloudEvent, giving you a complete, replayable audit trail.

BaaS-gateway model

The PM layer never connects to a custodian directly. All custody protocols — FIX, REST, SFTP, CSV — terminate at the BaaS gateway, so there is one integration surface, not N.

Cloud-native & modular

Stateless, horizontally-scalable services with clean interface contracts. Take the PM layer, the investing app, or both — no hidden coupling forces an all-or-nothing adoption.

The Gateway Model

One integration surface. Every custodian behind it.

Both front ends talk to a single gateway. The gateway owns every custody protocol — so adding a custodian never changes the PM layer, the portals, or the app.

Interpose Invest · white-labeled as your product

Wealth ManagementSelf-Directed AppRebalancingGIPS PerformanceDirect IndexingWhite-Label Portals

BaaS Gateway · single integration surface

Normalizes positions, transactions, and orders · owns FIX / REST / SFTP / CSV · routes rebalance orders to execution · enforces compliance checks

Your Native BaaS

you keep custody

Correspondent Custody

you keep custody

RIA Custodians

you keep custody

Crypto Custody

you keep custody

Interpose holds no assets. The broker-dealer or custodian of record is you or your custodian.

Multi-Custodian Connectivity

Aggregate every custodian into one data model.

Register a connection per account and the gateway pulls positions and transactions into a single normalized view — no matter where the assets actually sit.

Ingestion modes

APIReal-time

Real-time REST/FIX pull where the custodian exposes it — the preferred path.

FILE_IMPORTT+1 (feed-bound)

Scheduled CSV / SFTP ingestion for custodians without a live API.

Order routing for every custodian flows back through the gateway's execution path — the PM layer emits proposed orders; the gateway handles the per-custodian protocol.

Canonical normalization

  • Typed security identifiers — CUSIP, ISIN, ticker, or contract address — never a bare string
  • Monetary amounts as 4-decimal strings; share quantities as 8-decimal strings — never floats
  • Corporate-action timing quirks handled per custodian before data reaches your API
  • Equities, funds, and alternatives resolved to one canonical position model
{
  "security":  { "type": "cusip", "value": "037833100" },
  "quantity":  "125.00000000",
  "market_value": "23145.7500",
  "currency":  "USD"
}

Custodian-agnostic by design: bring your own brokerage rails, correspondent custody, or the outside custodians your advisors already use. Crypto assets flow through qualified third-party custody only — Interpose never self-custodies.

Two Operating Modes

Identical capabilities. Honest latency.

Every capability is the same in both modes. We're explicit that overlay mode is bound by the custodian's feed cadence — no real-time claims we can't keep.

DimensionReal-timeIntegrated ModeFeed-boundOverlay Mode
Position sourceShared event bus (CloudEvents)Gateway pull from custodian
Update latencyReal-timeFeed-bound — typically T+1
AUM & driftLive on every fillRefreshed on each sync
RebalancingFull engineFull engine
Performance & billingFull engineFull engine
Order routingThrough gatewayThrough gateway
Best forNative BaaS integrationAny external custodian

Real-Time Event Streams

Every state change is an event your systems can subscribe to.

In integrated mode, rebalances, fills, AUM changes, and billing events stream over CloudEvents 1.0 and WebSocket in real time — your ledger, your reporting, and the client app stay current with no polling.

Because positions are event-sourced, you can replay the full history of any account to reconstruct state at any point in time — the foundation for a clean audit and for reconciliation that catches breaks the moment they appear.

com.interpose.pm.rebalancing.completedcom.interpose.pm.billing.invoicedcom.interpose.baas.order.filled
POST/v1/custodians/connections
POST/v1/rebalancing
GET/v1/performance
POST/v1/billing/runs
GET/v1/stream

Compliance as Code

Regulatory rules that execute, not sit in a PDF.

Wash-sale windows, Reg-T, PDT, Reg SHO, and OFAC screening are versioned, tested policy — checked synchronously, with machine-readable rejection codes your systems can act on.

Wash-Sale (30-day)Reg-T Buying PowerPDTReg SHO LocateOFAC / AMLSEC Rule 17a-4 (WORM)GIPS MethodologyPer-Firm Data IsolationSOC 2 Type II (roadmap)

Talk to Engineering

See it running on your rails.

We'll walk your team through the gateway model, a sandbox, and a reference integration against your custody stack.

Book a Partner CallExplore the Front Ends