Introducing Railengine for Swift: Context That Follows Users Across Apple Devices
The context travels, identity doesn’t.
An agent is only as good as the context behind it. Without that context, users repeat themselves: re-explaining the project, re-pasting the notes, re-making yesterday’s decisions.
On Apple devices, that context is scattered by design. A thought gets captured on an iPhone, shaped on a Mac and needed again hours later, somewhere else. Users already expect their work to follow them across devices. Their agents should too.
That’s why we built Railengine for Swift, a native SDK that brings Railengine’s context ingestion and retrieval directly into Apple apps, without sending users’ identities along with their data.
What does Railengine for Swift do?
Railengine ingests your data, applies masks and transforms it, and serves it to agents in a form optimized for fast retrieval. The new Swift SDK brings that capability to Apple developers:
- Retrieve and search context from native Swift code
- Ingest data from Apple devices, including Embedded Swift
- Ground agents in the user’s own information so outputs stay accurate and current
- Pair with Railtracks for Swift so agents pull the right context at the right moment
Private by Design
The common approach to context is to centralize it: collect everything in one cloud store so the agent can reach it. That works until you look at what’s in the pile. Names, emails, health notes and client details all end up sitting next to the model, mixed into prompts, logs and vector indexes.
Railtown takes a different approach. Railengine separates what the agent needs to know from who the user is.
- Identity stays with the user. Personally identifiable information lives in the user’s own data layer and is retrieved from iCloud, under the user’s Apple Account. It never becomes part of the shared intelligence layer.
- Context is masked before agents see it. Railengine applies masks and transforms at ingestion, so agents work with the substance of a note, project or decision without the personal details attached.
- Identity rejoins only on the user’s device. When a response needs a name or detail back, it’s restored locally, inside the app the user already trusts.
The result is that applications get full useful context, while personal identity stays out of the systems doing the reasoning. Even if a prompt is logged or a model provider changes, there’s no PII in the stream to leak.
Why Apple?
- Continuity is already expected. Handoff and iCloud taught Apple users that their work follows them. Agents should too.
- Privacy is part of the platform. Many users choose Apple for how it treats their data. Railengine’s architecture works with that promise, not against it.
- One account, many devices. A user’s Apple account already connects their devices, giving agents a natural, user-owned boundary for context.
What This Unlocks
Continuous agentic experiences across Apple devices, built around privacy from the start. Capture something on your iPhone and ask about it on your Mac an hour later. The context travels. The identity doesn’t.
Not sure where to start?
Reach out to Railtown here to learn how Railengine can ground your agents in the data you already have.
