Arun Rajkumar

Co-Founder & CTO @PayWithAtoa | Building the future of UK payments | Open Banking | AI | FCA-Authorised | IIM Calcutta | We don't hire resumes. We hire intent.

[Arun Rajkumar @mickyarun]

I've spent UK FinTech Week reading dev threads on open banking.
Same misconceptions every time.
PSD2 is "OAuth for banks." Payment Initiation is "just a bank transfer." Open banking is "Stripe but cheaper."
None of that is right. Quick thread on what we got wrong (and learned). 🧵

[Arun Rajkumar @mickyarun]

@DanielGPT2022 https://t.co/9KNYPjoVc3 AI driven development platform, code to documentation, documentation to development modern alternative to Jira and Scrum

[Arun Rajkumar @mickyarun]

@audiencon AI driven development framework with 12 special agents alternative to jira https://t.co/9KNYPjoVc3

[Arun Rajkumar @mickyarun]

@RoundtableSpace Agent Driven platform , where 12 Ai agents work together https://t.co/9KNYPjoVc3

[Arun Rajkumar @mickyarun]

https://t.co/9KNYPjoVc3

[Arun Rajkumar @mickyarun]

A lot of people have asked me the same question lately:
"How do you run an engineering team on AI?"
Here's my honest answer: I stopped running it the old way.
Sprints. Scrum. Standups. Planning poker. Jira boards no one updates. None of it was built for a team where AI writes the first draft, estimates the work, and tests the code.
I kept bending these tools to fit AI-driven development. They kept snapping back to 2010.
So I built my own. Twelve AI agents that carry a feature from a chat message to production — triage, spec, design, tests, deploy, retrospective. Humans make the decisions. Agents do the busywork.
And I'm open-sourcing it. Apache 2.0. Self-hosted. Your data stays yours. An independent project — built solo, on my own time.
Here's a look inside the virtual world we build in 👇

Sprints felt broken. So we replaced them.
#BuildInPublic #AI

[Arun Rajkumar @mickyarun]

@joni_vrbt https://t.co/9KNYPjoVc3 Agent Development Platform

[Arun Rajkumar @mickyarun]

@DanielGPT2022 @X https://t.co/9KNYPjoVc3 An open source agent development platform alternative to Jira, Scrum

[Arun Rajkumar @mickyarun]

@buildinpublic Agent Development Platform alternative to scurm, sprint and Jira https://t.co/9KNYPjoVc3

[Arun Rajkumar @mickyarun]

@TrueLayer Can confirm from the merchant side. We run Pay by Bank for UK merchants at half the cost of cards — but the thing that converts the skeptics isn't the fee, it's settlement speed. Cost gets them to try it. Speed makes them stay.

[Arun Rajkumar @mickyarun]

@TokenizedPod @sytaylor @anthonysoohoo @MoneyGram @LucaProsperi @m0 Remittance is where this actually makes sense — real corridor, real cost pain, real speed problem. Curious what the on/off-ramp fees net out to vs the rails it's replacing. That's usually where these quietly lose the savings.

[Arun Rajkumar @mickyarun]

@sytaylor The interesting question isn't who issues them — it's whether they clear faster and cheaper than the rails we've got. From the Pay by Bank side, instant + low-cost is the bar. Stablecoins only win where they beat it. You seeing banks issue, or just custody?

[Arun Rajkumar @mickyarun]

@harshilmathur @Razorpay The MCP layer is the one most teams are sleeping on. We've been feeding microservice context to agents this way for months — the unlock was never the interface, it's the context you hand the agent. Good to see all four ship. Which one's pulling the most usage so far, CLI or MCP?

[Arun Rajkumar @mickyarun]

A tutor got quoted £3,000 for a website just to collect payments online.
She didn't need a website. She needed a payment page.
@PayWithAtoa Payment Pages — create one in minutes, share a link, get paid. Half the cost of cards. FCA-authorised.
https://t.co/ImR3VIPJQz
#OpenBanking

[Arun Rajkumar @mickyarun]

The job isn't writing code anymore. The job is judgment.
And judgment is the one thing you can't generate with a prompt.
Full article with the design thinking challenge: https://t.co/wac8ClpBKG
#AI #Hiring #CTO #StartupLife #BuildInPublic

[Arun Rajkumar @mickyarun]

The interesting answers don't start with a tech stack. They start with questions.
Who's the audience? Where do they already scroll? What's the 3-second hook? What makes someone WANT to share this?
That's the thinking AI can't do. And it's what I test for in every interview.
How would YOU approach it?

[Arun Rajkumar @mickyarun]

But the 20% isn't just code. It's design thinking.
Before Atoa, I worked with clients showcasing at CES. One brief: a chocolate brand wants emotion-recognition software. Detects your mood, recommends a chocolate, goes viral.
If your first answer is "I'll build a mobile app" — that's a reject.
You solved for delivery before virality.

[Arun Rajkumar @mickyarun]

The candidates who catch this aren't the best coders.
They're the ones who think about consequences before syntax. Who ask "what happens if this gets called twice?" before "how does this work?"
That's the 20% AI can't do.

[Arun Rajkumar @mickyarun]

So we flipped it.
We give candidates a webhook handler for processing payments. Works perfectly. Clean code. Returns a 200.
What's missing: idempotency.
If the bank retries — and banks always retry — the customer gets charged twice.
The code is correct. The system is broken.

[Arun Rajkumar @mickyarun]

We stopped asking candidates to write code in interviews.
Instead, we hand them code an AI agent already wrote.
It looks clean. It passes tests. The types are correct.
But it's wrong. And the ones who find why — those are the hires.
Here's what changed and why 🧵

[Arun Rajkumar @mickyarun]

The old interview tested: can you write syntactically correct code under pressure, from memory, with someone watching?
That's a real skill.
It's just not the skill that matters anymore. An AI agent does that part faster than any human. And it doesn't get nervous.