Miftahul Arifin
Currently at S16 Research Ventures · 6+ years · East Java, Indonesia

Backend engineer building payment systems, APIs and developer tools.

I design and run backend systems that handle real money: a multi-chain crypto payment gateway, a rupiah payments and bookkeeping platform, and the APIs around them. AI agents write more of my code every month, so I spend my time where they can’t be trusted alone: system design, security boundaries and shipping safely.

See what’s in production GitHub profile ↗
2payment platforms live in production7blockchains one gateway settles on7open-source tools I use myself160+GitHub stars, 70+ forks from other devs ↗
Where I’ve built and learnedS16 Research VenturesS16 Research VenturesMoladinMoladinBibitBibitElnusaElnusaITBITB
Stack I ship withC# / .NETSQL ServerPostgreSQLGoTypeScriptRustSolidityCosmos SDKDockerAzure
In production

Real money, real merchants, in production.

Two platforms I work on as a backend engineer at S16 Research Ventures: what they do and where I fit in.

Runegate

runegate.com
Backend EngineerS16 Research Ventures

A crypto payment gateway for merchants. Businesses accept crypto payments, send invoices and payment links, and move between crypto and fiat across seven blockchains.

What I work on
  • Backend services and APIs for payments, invoicing and payouts
  • Integrations with custody, banking and payment partners
  • Platform modernisation, security hardening and automated testing
PaymentsMulti-chainMerchant APIs
Overview →runegate.com ↗

Qelola

qelola.com
Backend EngineerS16 Research Ventures

Payments and bookkeeping for Indonesian businesses. Invoices, payment links, checkout and payouts in rupiah, with the books kept automatically.

What I work on
  • Payment flows, payouts and the partner API
  • Automated double-entry bookkeeping and financial reports
  • Multi-tenant security and data protection
PaymentsAccountingSaaS
Overview →qelola.com ↗
Open source

Tools I built because I needed them.

Each one started as a problem in my own week. Grouped by what they’re for, not what they’re written in.

For working with AI agents

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Antlings session view with lead and worker ants, a subagent plan, and a code diff waiting for approval

Antlings

Run Claude Code on your own server and drive it from your phone. Every subagent shows up as a worker ant, so you can see who’s stuck.

Approve tool calls with the diff in front of you, get a push when one is waiting, sign in with a passkey.

Self-hosted · PWA · MITDetails →GitHub ↗
Voice session · screenshot coming

Kawan

A voice companion for practising spoken English that remembers you, in plain Markdown files you can open and edit.

Speech-to-text and text-to-speech run on your machine. Audio never leaves it; only the text goes to the model you choose.

Local-first · BetaDetails →GitHub ↗

EmberTerm

A Windows terminal that reopens exactly where you left off, tabs, splits and folders included, so agent sessions survive a reboot.

Git Bash, WSL, PowerShell and cmd side by side. Warns before closing a running command. No account, no telemetry.

Windows · Tauri · MITDetails →GitHub ↗

For running servers and APIs

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Astral dashboard showing live CPU, memory, network and storage, a 6-hour history chart and top processes

Astral

A server dashboard you copy onto a box and run. Live stats, a week of history and alerts, with nothing to install.

7.1 MBone binary
1.5 msto launch
8.9 MBpeak memory
Rust · Svelte · SQLiteDetails →GitHub ↗

Project Structure API

The API skeleton I wish I’d had: auth, roles, rate limits, tracing, docs and CI already decided, so day one is about the product.

139GitHub stars
23forks
Node · TypeScript · PostgresDetails →GitHub ↗

For building on blockchains

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Dexplorer dashboard for a Cosmos chain with live blocks and transactions

Dexplorer

A block explorer for any Cosmos chain that runs entirely in the browser. Point it at an RPC and you get validators, governance and IBC, with no backend and no database.

27 stars · 47 forksDetails →Live demo ↗GitHub ↗
Xylem streaming the latest blocks and transactions from Base

Xylem

The same idea for EVM chains. Watch blocks and transactions stream in from a local Anvil node or your own L2, where hosted explorers don’t reach.

EVM · zero backendDetails →GitHub ↗
See all 17 projects
Writing

Notes from the work.

All 8 articles →
Oct 17, 2026 · Architecture · RustWhy cat bigfile freezes webview terminals: backpressure from ConPTY to xterm.jsJun 3, 2026 · Blockchain · SecurityGas sponsorship without draining your balanceMay 22, 2026 · Blockchain · ArchitectureHow ERC-4337 actually works: bundler, paymaster, entrypointFeb 27, 2026 · AIContext Rot: Why Giving AI Too Much Info Can Ruin the Results