Extensions Overview
CRE Connect extensions are first-party modules that wrap CRE Connect with service-specific helpers. Each extension provides three things:
- An operation builder that packs calldata for the service's smart contracts so applications don't have to manage the ABI themselves.
- A typed event decoder so service-specific events arrive as strongly-typed values rather than untyped maps.
- One-call watcher provisioning. CRE Connect ships pre-packaged watchers for the service so a single call provisions every watcher the service needs.
Extensions are independent modules; applications consume only the ones they need.
Available extensions
| Extension | Use when |
|---|---|
| DTA (Digital Transfer Agent) | Tokenised funds: subscriptions, redemptions, distributor lifecycle. |
The DTA extension uses contract versioning — each deployed contract ABI is exposed as a separate sub-module (/v1, /v2, …). This versioning matches the on-chain contract ABI version and is independent of the extension's own semantic version. The CRE Connect documentation focuses on the v2 ABI.
Why extensions matter
- No ABI bookkeeping. Calldata packing happens inside the extension; bumping a contract version is a single dependency upgrade.
- Typed events. Each on-chain event is decoded into a strongly-typed value with named fields, instead of opaque strings or maps.
- One-call watcher provisioning. Naming the extension's service is enough for CRE Connect to set up every watcher the service requires.
- Backwards-compatible upgrades. When an event schema or operation signature changes, the extension version bumps and applications get a compile-time signal rather than silent runtime drift.
Anatomy of an extension
Every CRE Connect extension exposes the same shape:
- An operations surface — one builder per on-chain action the service supports.
- An events surface — one typed value per on-chain event the service emits, plus a single
Decodehelper that dispatches a verifiable event to the matching typed value. - A watcher bundle — the service descriptor (name plus the set of events it covers) consumed by CRE Connect to provision the service's watchers in one call.
What's next
- DTA Overview — the first available CRE Connect extension.
- Concepts → Extensions — design philosophy and how extensions compose with the core product.