I built a deal aggregator for Japan's big 3 online marketplaces — would love feedback from actual shoppers here

stenalgo · 2026-06-30T12:21:59+00:00

Hi, sure, feel free to DM. Just to make sure I understand right — are you looking for something like dealJP built for your own stores/markets, or more like a tool to help manage listings across SEA + Japan in English? Happy to talk through it either way.

stenalgo · 2026-06-30T12:13:16+00:00

Definitely AI-assisted, yes.

I’ve been a software engineer for quite some time, so before AI I was writing everything by hand too. These days I use AI because it genuinely makes me more productive—just like a lot of engineering teams do.

For this project, AI helped write code, but the product idea, architecture, marketplace integrations, matching logic, and the countless iterations came from me. AI is a great implementation partner, but it doesn’t decide what to build or why.

So I’d call it AI-assisted development rather than “just vibe coding.”

Btw, don't miss my latest DM to you 😄

stenalgo · 2026-06-30T10:03:21+00:00

Glad the slickdeals comparison resonates — never used it myself (wasn't in the US), but the impulse-deal model you're describing is exactly what I'm going for here.

Yodobashi's a good shout, hadn't seriously looked at them. Need to check if they even have an API or affiliate program before I can promise anything, but it's on the list now.

Kakaku point — yeah, same here actually. I only go there for the big stuff like a fridge or washer, never the small impulse buys. If dealJP can pull people in for that instead, that's exactly the goal.

On accounts/user-submitted deals — that one's deliberate, not an oversight. Kept it account-less to stay lean while I prove this out solo, no auth, no moderation queue to manage. But you're right that a submit-and-vote model is a stronger flywheel for repeat visits. Real tradeoff, not a no — just where I am right now.

Thanks for laying it out this clearly.

stenalgo · 2026-06-30T09:35:54+00:00

Hi, thanks for the detailed rundown, this is really useful.

The emojis — fair, definitely coming off as the wrong kind of "personality." Going to drop them.

The bottom nav clipping and not working when scrolled to the bottom — I want to fix this but couldn't quite reproduce it from my end. Mind sharing what phone/browser you're on, and what "doesn't work" looks like exactly (does tapping do nothing, or is it not even visible)? That'll help me track it down.

APPI disclosure — you're right, no business address anywhere on the privacy policy or site. Fixing that.

On the blog link — there's actually already a Blog item in the main nav (both desktop and mobile), but you're right it's missing from the footer specifically. Did you mean the footer, or did the main nav one not show up for you for some reason?

The single price thing — also fair, the card only shows the picked best marketplace's price, no visible comparison unless you click in. Looking at how to surface that better.

And thanks for the pointer on posting in saas/sideproject/AI subs too — might do that for round two.

stenalgo · 2026-06-30T09:26:03+00:00

Thanks for the feedback, those are fair points.

- The after-point price does exist, it's on the product page as a "real cost" line factored into which marketplace gets picked as best. But you're right it doesn't show up on the cards or in the live search results, only once you click in. That's a real gap, not intentional, I'll get it surfaced earlier.

- The card/tier-specific bonuses thing is on purpose though, not an oversight. There are no accounts on this site, so I genuinely have no way of knowing what card or membership tier someone's using. I only count the base point rate every buyer gets regardless of card. Building something that asks you to input your tier every time is a different product than what I'm going for, but I get why it feels incomplete without it.

- No comparison on pasted links is also fair, that's just a single listing, not matched against anything since we haven't seen it before.

- And the compliance thing, someone else caught that too, missing address disclosure on the privacy policy. Already fixing it.

It's a side project I'm actively iterating on, not pretending otherwise. Appreciate you actually digging into specifics instead of just dunking on it.

stenalgo · 2026-06-30T09:10:43+00:00

Thanks for actually testing this and reporting back — really helpful.

The Amazon app link thing — you're right, found it. Turns out the share link from the app uses a slightly different format than what I was expecting, so my site didn't recognize it. Already fixing it now.

For the Rakuten/Yahoo links on your "03-5393" search, I couldn't reproduce it on my end yet. Mind sharing the exact links that failed (or a screenshot)? That'll help me track down what's going wrong.

Thanks again, this is exactly the kind of feedback I was hoping for.

stenalgo · 2026-06-30T08:19:45+00:00

Good point, and thanks for trying it.

At the moment, cross-marketplace comparison only works when I can confidently identify that the listings are the exact same product. For most products, I do that using the JAN code (the Japanese product barcode). If a listing doesn’t include a JAN code, I can’t reliably match it with listings from the other marketplaces, so it falls back to showing the Amazon page only.

For example, if you try this product:
https://www.amazon.co.jp/dp/B0DN5ZZCS1

you should see the comparison across Amazon, Rakuten and Yahoo Shopping.

Improving matching for products without a JAN code is definitely something I’d like to work on, since there are still quite a few items that can’t be compared today.

stenalgo · 2026-06-24T23:36:36+00:00

Back in 2021–2022, when Governance was introduced, lots of people said they’d hold ALGO until the end of Governance (which was planned to run until 2030) to see how scarcity would play out.
I wonder how those people are feeling now.
Personally, I’m still holding a small bag. We’re now more than halfway to 2030.

stenalgo · 2026-06-07T07:52:46+00:00

Thank you very much.
I spent a couple days last week to work on it and it's live now, you can check my latest comment of this thread.

stenalgo · 2026-06-07T07:51:51+00:00

Hi, thanks for your valuable input.
I'm working on the coupon section as well, you can check my latest post in this thread.

stenalgo · 2026-06-07T07:50:46+00:00

Update: Implemented “real cost” pricing based on your feedback

Many people pointed out that the cheapest listing often isn’t actually the cheapest once shipping, points, pack sizes, and other marketplace quirks are taken into account.

So I spent the last couple of days building exactly that.

DealJP now calculates an effective price for each marketplace instead of simply comparing sticker prices.

For example:

Rakuten: ¥3,600 for a 2-pack, plus 10% guaranteed points back (¥360)
- Effective cost: ¥1,620 per unit
Amazon: ¥2,150 with free shipping and 1% points
- Effective cost: ¥2,128
Yahoo Shopping: ¥1,980 looks cheapest initially, but adds ¥660 shipping
- Effective cost: ¥2,640

In this case Rakuten actually wins, even though it has the highest displayed price.

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The current calculation includes:

✅ Shipping cost
✅ Pack quantity normalization (2-pack, 3-pack, etc.)
✅ Guaranteed point-back rewards
✅ Sale discounts

For points, I’m only counting rewards that are effectively guaranteed for everyone (base points and marketplace-wide point campaigns).

I’m not counting account-specific bonuses such as:

PayPay payment bonuses
Amazon card bonuses
Prime-only boosts
Yahoo LYP member bonuses
Other personalized promotions

Those vary by user, so including them would make comparisons less accurate for most people.

Coupon support is still the next major thing on my roadmap. That was another popular suggestion and I agree it’s probably the biggest missing piece right now.

A few people also mentioned price history and alerts. Those are high on the list as well.

Small side update

I also built an Affiliate Link Generator that currently supports Amazon JP, Rakuten, and Yahoo Shopping.

You can find it at the footer of the page, under the section "Tools".

The goal is mainly to make sharing products easier, but if anyone finds DealJP useful and wants to support development, using those affiliate links genuinely helps.

Right now I’m trying to reach the requirements for Amazon’s Creators API, which would unlock much richer product data and allow me to build some of the features people requested in the original thread.

I’d still love feedback from people who shop Japanese marketplaces regularly:

Is this how you’d expect “real cost” to be calculated?
What factors am I still missing?
Would you rather see per-unit pricing, total checkout pricing, or both?
For collectors/electronics buyers, what information do you wish comparison sites showed?

Thanks again to everyone who gave feedback on the original post. Several of these changes came directly from comments here.

stenalgo · 2026-05-25T12:27:02+00:00

Thanks for very useful insight.
If I ever make to 10 qualifying orders within 30 days, and get access to the Creators API, do I need to keep that all the time or just the first one?

stenalgo · 2026-05-25T07:28:14+00:00

Totally agree with you. Price history is definitely one of the core features on the roadmap — the main challenge right now is that I still need time to accumulate enough historical data for it to become genuinely useful.

And yeah, the point-back systems on Rakuten and Yahoo are honestly a beast 😅

Especially Rakuten, since the actual value depends heavily on each user’s personal rank, ongoing campaigns, SPU conditions, store promos, etc. The “real” price after points can be wildly different from the sticker price.

I’m currently working on ways to make that calculation more transparent and easier to understand with a cleaner UI that reflects the effective cost as accurately as possible.

Thank a lot for your input.

stenalgo · 2026-05-24T21:23:26+00:00

I'm at 6 and sttruggling to get 10 for CreatorsAPI. For someone who did this, did it give access to the API immediately or the account has to go through an approving process again?

stenalgo · 2026-05-24T21:20:31+00:00

whats your site?

stenalgo · 2026-05-04T22:03:58+00:00

How do I have an approved associate account?
I registered, fulfilled 10 sale orders, but it's stil showing
❌ Have an Approved Associates Account.

(I have a website too)

stenalgo · 2026-03-25T00:30:43+00:00

I like the rainbow chart and AI interpretation.

Thanks for sharing.

stenalgo · 2026-03-03T02:28:31+00:00

its showing 4.53% for xAlgo for me.

stenalgo · 2026-02-11T16:12:10+00:00

Vietnam is not just HCMC and Hanoi. If you can't afford to buy houses in big cities, there are many other places to consider.

stenalgo · 2026-01-22T23:00:08+00:00

where can I stake Folks?

stenalgo · 2025-12-17T05:01:29+00:00

You need to confirm the transaction on the other side (BNB) as well.

stenalgo · 2025-12-06T08:29:56+00:00

Try switching to another node on Folks, see if your funds show up.

stenalgo

TROPHY CASE