AWS has published a way to preview a web app inside an Amazon Bedrock AgentCore session while a coding agent is still editing it. Developers can watch changes appear in the browser without redeploying after each edit, although this is a development preview, not a way to host the finished app for users.
AWS AI Watch analysis
What happened
Amazon Bedrock AgentCore Runtime Session endpoints give each session an authenticated URL to reach selected ports. AWS’s walkthrough uses one port for a website and another for a status route; a local endpoint adds the developer’s credentials so a browser can display the preview and its live updates. The AWS walkthrough includes a sample that pairs a chat interface with a running Vite website.
The endpoint forwards HTTP and WebSocket traffic to ports the developer allows. Each request must be authenticated, and the URL lasts only for the session. AWS says the feature works with microVM runtimes, not the Instances compute type; inbound connections through AWS PrivateLink are not supported.
Why it matters
The useful change is the feedback loop: ask an agent to alter an app, then inspect the result as it appears, rather than waiting for a separate deployment. That makes it easier to review what an agent is building while work is under way.
The guardrails also define the feature’s limits. Developers choose which ports are reachable, and the session endpoint is temporary and authenticated. It is a practical workspace for building and testing, not a public front door for the finished site.
Our read
This is a tangible improvement to the unglamorous bit of agent-assisted coding: checking whether the thing actually works. The live preview is the headline; the per-session access controls are what make it more than a convenient tunnel. Try it as a development workflow, but keep deployment and user access on a proper hosting service.
What to watch
- Whether AWS adds support for runtimes using the Instances compute type.
- How the SDK and local endpoint tools develop beyond the sample workflow.
- Whether similar live-preview loops become standard across coding-agent platforms.
Discussion spark: When reviewing an AI-built app, would you trust a live in-session preview, or should agent changes still go through a separate deployment before anyone tests them?
Sources and evidence
- Preview web apps live as your coding agent builds them with Amazon Bedrock AgentCore runtime (30 October 2026, 21:40 UTC)
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