Backend connectivity

Six different tools in this repo can connect a UI5 app to a backend. They cover different needs — local-only proxying, embedding a CAP server, BTP destinations, productive deployment with @sap/approuter. This page is the head-to-head.

Table of contents

1. Comparison
2. Tool descriptions
   1. cds-plugin-ui5
   2. ui5-middleware-cap
   3. ui5-middleware-approuter
   4. @sap/approuter
   5. dev-approuter
   6. ui5-middleware-simpleproxy

Comparison

	cds-plugin-ui5	ui5-middleware-cap	ui5-middleware-approuter	@sap/approuter	dev-approuter	ui5-middleware-simpleproxy
Productive use	❌	❌	❌	✅	❌	❌
UAA support	(✅)	❌	✅	✅	✅	❌
BTP destinations	❌	❌	✅	✅	✅	❌
WebSockets	❌	❌	✅	✅	✅	✅
Development use	✅	✅	✅	✅	✅	✅
Embeds UI5 middlewares	✅	✅	✅	❌	✅	✅
Embeds CAP server	❌	✅	(✅)¹	❌	✅	(✅)¹
Mock UAA support	✅	✅	(✅)¹	❌	✅	(✅)¹
Server processes	1	1	2 (UI5 + AppRouter)	1 + required	2 (AppRouter + CAP)	1 + required

¹ via proxy

Tool descriptions

cds-plugin-ui5

cds-plugin-ui5 is a CDS server cds-plugin that integrates UI5 CLI based projects (UI5 freestyle or Fiori elements) into the CDS server via the UI5 CLI express middlewares. The UI5 / Fiori elements project just needs to live in the CDS server’s app folder or be a dependency of the CDS server.

ui5-middleware-cap

ui5-middleware-cap improves the development experience for the SAP Cloud Application Programming Model (CAP) by embedding a CDS server inside the UI5 dev server. The CAP project must be added as a dependency so the server can be discovered and attached. Pre-defined routes in the CAP server are reused.

ui5-middleware-approuter

ui5-middleware-approuter makes destinations configured in SAP Cloud Foundry or SAP XS Advanced available for local development, using http-proxy-middleware under the hood.

@sap/approuter

@sap/approuter is the production application router for SAP BTP / Cloud Foundry / XSA. Components access target services through the application router only when no JWT is yet available (e.g. when a user invokes the app from a browser); already-authenticated callers reach the target services directly.

dev-approuter

dev-approuter is a dev-time-only wrapper around @sap/approuter that can serve UI5 and CAP apps added as (dev)dependencies to its own package.json. Useful when you want approuter behaviour (UAA mocking, destinations, sessions) without a separate UI5 dev server.

ui5-middleware-simpleproxy

ui5-middleware-simpleproxy is the simplest of the bunch — a lightweight express proxy for UI5 dev server. No UAA, no destinations, just forwarding.

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Need help picking? Use the extension selector or open a question on the OpenUI5 Slack #tooling channel.