From Claude Code to Pi. Open models, lower cost.

WebJourney started with the Claude Code SDK, which limited it to Claude models. To reduce agent costs, it moved to Pi and open-source models—while keeping the same AgentSky API and cloud runtime.

Claude → Pi

same API

Shihang Wei

Founder, WebJourney

Customer

AI builder for full-stack apps and launch-ready sites

Challenge

Move beyond Claude-only models and reduce agent costs without rebuilding the product backend.

AgentSky

One API across the harness, sandbox, state, tools, and recovery.

What WebJourney builds

Visit WebJourney

A full-stack builder where the output has to be ready to ship.

WebJourney lets customers build full-stack and AI apps, landing pages, and websites by chatting with an AI agent. Its public product includes automated tests, deployment, scaling, and SEO.

WebJourney initially used the Claude Code SDK to power that work. But the SDK limited model choice to Claude. To lower the cost of running agents, WebJourney moved to Pi so it could use open-source models without replacing the AgentSky API or taking ownership of the cloud runtime.

The same boundary leaves WebJourney free to move again when another harness or model better fits its quality, speed, or cost requirements.

How it works

The product stays theirs. The agent runtime is AgentSky.

WebJourney started with Claude Code

The Claude Code SDK powered the agent work, but limited WebJourney to Claude models.

It needed lower-cost models

To reduce the cost of running agents, WebJourney needed access to open-source models beyond the Claude family.

AgentSky moved the runtime to Pi

Because WebJourney already called one AgentSky contract, it could switch the harness and models quickly while keeping the product API and cloud runtime stable.

Why AgentSky

Move from Claude-only to open models without rebuilding.

Move beyond model lock-in

Pi gave WebJourney access to open-source models instead of limiting the product to the Claude family.

Lower the cost of every agent

WebJourney could choose lower-cost models for its workload without building and maintaining another agent backend.

Stay ready for the next migration

AgentSky absorbs harness and model differences, so WebJourney can change stacks again without adding another runtime backend.

Evidence note

WebJourney’s official site describes its full-stack and AI app builder. The Claude Code-to-Pi migration and cost motivation are customer-provided implementation context; this page does not publish a customer volume, savings percentage, or universal outcome claim.

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