How Hosan Swee Built KiasuMiles to Find the Best Credit Card for Each Purchase

Choosing a miles card sounds simple until the answer changes with the merchant, spending category and monthly reward limits. Hosan Swee and his wife faced that problem while managing about a dozen cards. Swee used AI to build KiasuMiles, which recommends a card from a user’s own wallet for a particular purchase. 235

From a card collection to a purchase-specific answer

Rather than asking which Singapore credit card is best in general, a user can describe what they are buying and how they will pay. Reported example questions include paying for GrabFood in-app and shopping at Cold Storage with Apple Pay. KiasuMiles matches that context against an internal database of card rules, including minimum spending thresholds, monthly miles caps and eligible spending categories. 2

That structured lookup is the important distinction from asking a chatbot to recall card benefits unaided. It gives the assistant rules to consult, but it does not guarantee that every recommendation reflects the latest terms or that a purchase will qualify. The available source excerpts do not verify the reported database size, its update frequency or the full set of payment-method rules.

How users connect KiasuMiles

The KiasuMiles site tells users to choose an AI app that supports external tools, connect KiasuMiles and ask about a purchase. It says users can keep their card list in the same conversation for subsequent questions. Separate listings identify a hosted MCP server and a skill intended for Claude Code and Codex. Setup therefore depends on the assistant being used; there is no single connection step that applies to every app. 561

Swee’s use of AI to create the service is documented, and OpenAI describes Codex as a tool for assigning coding tasks through ChatGPT. The available excerpts, however, do not establish exactly which parts of KiasuMiles Swee built with Codex or what role a product called ChatGPT Work played. 2311

What a DBS yuu suggestion at Cold Storage means

Cold Storage is a participating yuu merchant, and DBS advertises up to 36x yuu Points, equivalent to 18% cash rebates or 10 miles per S$1. Those are alternative ways to use the points—not rewards earned together. 71415

The headline rate needs context. A DBS promotion page describes a component worth 5% cash rebates or 2.8 miles per S$1 without minimum spending, plus an additional 13% or 7.2 miles per S$1 after at least S$800 of spending at four different participating merchants in a calendar month. Check the current card terms, applicable caps and whether the intended payment method qualifies before treating the maximum rate as the return on a particular purchase. 13

The useful lesson for first-time builders

KiasuMiles illustrates a manageable way to frame an AI-assisted project: begin with a repeated decision, define the information needed to make it, and test the result against real examples. For a card tool, that could mean starting with a few cards, recording their minimum spends, caps and eligible categories, then checking recommendations for specific purchases before adding more rules. Those are practical takeaways from the product’s design—not verified quotations or a documented step-by-step account of Swee’s development process. 23

AI can help turn scattered information into a working tool, but a plausible answer is not the same as a verified one. For rewards advice, the final check remains the bank’s current conditions and the details of the transaction. 213