Why this exists
Building ramp and bank-linking flows from scratch means a separate KYC review per provider, per-region payment rail integrations, and ongoing institution coverage. Meld consolidates those into one provider that Sumvin operates server-side. Partners call the Sumvin Platform API; Sumvin handles the Meld credentials, customer mapping, KYC passthrough, and webhook routing.What ships today
| Slice | Status | What it covers |
|---|---|---|
| Client setup | Shipped | How Sumvin’s Meld client is configured and what partners need to know about its environment, customer mapping, and webhook plumbing. |
| KYC passthrough | Shipped | Sharing the user’s existing SumSub KYC outcome with Meld so the user is not re-verified inside the Meld widget. |
| Bank linking | Shipped | Linking a user’s bank account through the Meld widget — institution discovery, link initiation, account population, processor token issuance. |
| Buy / sell | Early access | Hosted Meld sessions for fiat to crypto and crypto to fiat against a Sumvin user. |
| Off-ramp | Early access | Settling a user’s crypto to a linked fiat account. |
How it composes
-
Customer record — every user with any Meld-touching flow gets a Meld customer record on first use, keyed by the Sumvin user’s
external_id. Subsequent flows (KYC passthrough, bank linking) reuse the same customer. - KYC envelope — the user verifies once with Sumvin (via SumSub). On a Meld flow, Sumvin shares the verified KYC result with Meld so the user is not re-verified.
-
Bank linking — the partner initiates a link with the institution selected by the user; Sumvin returns a Meld widget URL. Account data and balances arrive via webhook.
POST /v0/accounts/link— Initiate a bank link. - Webhooks — Meld posts events to Sumvin (KYC status, bank connection, account update, transaction aggregation). Sumvin consumes these internally and updates the partner-visible state on the relevant resources.
Where to start
| Concern | Where to go | When |
|---|---|---|
| Client model | Client setup | First — before any Meld-backed flow |
| KYC passthrough | KYC passthrough | When users hit Meld with an existing SumSub result |
| Bank linking | Bank linking | Linking a user’s institution via the Meld widget |
| Reference | Reference | Endpoints, payloads, and error codes for the shipped slices |
Related
- Ramp sessions — conceptual model behind Meld-backed sessions
- KYC and attestation — how Sumvin’s KYC outcome gets reused downstream
- Onramp via Meld quickstart