Hands-on technical leadership, with 20 years of craft behind it.
I'm Dhruva Sagar, a software craftsman in Bangalore, two decades into architecting, building, and shipping software in Rust, Go, Ruby, Python, Elixir, TypeScript, and Java. Today I work with early-stage teams as a fractional CTO and technical advisor: architecture, roadmap, hiring, and the hard decisions. The same decisions I've been making while leading engineering teams for 12+ years, backed by the ISB CTO Program. Beyond the core craft, my deepest practice is agentic engineering: building complex software with coding agents, at scale. I still write and ship open-source software myself, much of it that way.
Core philosophy
Build like it will outlive the roadmap.
Agentic engineering at scale
The deepest thread in my current research
Lattice is the testbed: two coding agents, Claude Code and opencode, build against one shared capability surface, driving a multi-threaded editor core through phase ledgers, design documents, and CI-ratcheted performance gates.
The learnings: agents need capability gates, not prompt prayers; plugin hosts that sandbox their output; trust modes that scale from "review everything" to "ship it"; and a record of the system they can read. That practice, agents at scale without losing the craft, is what I bring to teams building complex software.
Architecture before velocity
The fast path is a trap if it compounds into a ball of mud. I design for the system's tenth year, not its tenth sprint. I take technical debt as a decision, not an accident.
Slow, deliberate building
In open water you don't kick harder, you look further ahead. Sustainable, stable systems come from measured, deliberate progress, the same discipline as a decade with the cube.
Hands-on leadership
I don't just draw diagrams. I write the foundational scaffolding, set the golden paths, and mentor by example, leading the work, not just the roadmap.
Engagement models
Ways to work together
Three ways to work together, from a few hours a week to full-time delivery. Predictable commitment, no equity required.
Advisory
Senior judgement on demand: stack selection, RFC reviews, technical audits, and honest answers to hard questions. The lightest engagement, a few hours a week on your cadence.
Book a call →Technical expertise
Hands-on work without a full-time hire: architecture, code, and infrastructure reviews, modernization and digital transformation, agentic engineering workflows. More involved than advisory, still not full time.
Book a call →Fractional CTO & delivery
End-to-end product and feature delivery: roadmap, architecture, hiring, and leading the build. For teams that need a technical leader, effectively full time.
ISB CTO Program · Class of '25
Book a call →Not sure what you need? Email me and we'll figure it out.
The stack, at a glance:
Selected work
Things I've built and shipped
Recent work
Lattice
Founder & architect, pre-1.0, building in public
A modal, GPU-accelerated, plugin-first text editor in Rust: vim's editing grammar, Emacs-class extensibility through sandboxed WASM plugins, and a UI thread that never blocks, with a ~3,600-line design document behind it.
Built with two coding agents against one shared capability surface. The full practice is detailed in my core philosophy.
Creator
An open-source framework for AI-native engineering knowledge systems, capturing what an organization knows in a form both engineers and AI systems can use.
Creator
A Claude Code plugin that turns Ruby and Rails upgrades into a phased, verifiable process: audit, plan, fix, verify, commit. Born from the Mindbody engagement.
Client work
Selected engagements, all delivered during a 12+ year tenure at Tarkalabs.
Principal Consultant · 12+ years
Twelve years architecting and shipping for product companies: TuneCore, Aisle, Moove, JiffleNow, Gaea Global, Klstr, and more. The full record is on the portfolio page.
Yamaha Creator Pass
Fractional CTO · Tarkalabs
Joined to coordinate cross-functional teams building the platform, conduct architecture reviews, drive people development, and lead CCPA/GDPR compliance.
Mindbody
Technical Architect · Tarkalabs
Planned and delivered a complex Rails upgrade across many services, heavily using AI for automated upgrades. The engagement that produced ruby-upgrade-toolkit.
Side projects
stromalytics
Prototype
AI-powered swimming technique analysis: upload a video of a swim, get biomechanics metrics and a personalised coaching report with drill recommendations.
Prototype
Create and share business canvases to pitch startup ideas. The canvas that used to live on a whiteboard, made shareable.
Open source
The full record, every client, project, and repository, is on the portfolio page.
See the full portfolioWriting
Notes on code, craft, attention, and the examined life.
Contact
Let's build something worth keeping.
Leadership and advisory for early-stage teams, agentic engineering at scale, or a second pair of eyes on an architecture, in any stack and any language. I'm happy to talk it through.
Book a call