Igal Klebanov

Senior Software Engineer in Tel Aviv. I co-lead Kysely and work on TypeScript and database tooling in my free time.

Open source

01
Kysely
A type-safe SQL query builder for TypeScript.
What a ride! we made it to 20M+ downloads per week on npm and 14k+ github stars.
Used by teams at Mozilla and Bluesky, and built into Better Auth, Langfuse, AWS Blocks, MikroORM, and OpenClaw.
1. Co-lead
  Apr 2025 – present
  Project direction and API design.
2. Member
  Mar 2023 – Apr 2025
  Reviewing contributions, guiding contributors, shaping process, and building the first-party ecosystem around Kysely.
3. Collaborator
  Sep 2022 – Mar 2023
  Actively involved in the community and discussing design decisions with Sami, the author.
4. Contributor
  Jul 2022 – Sep 2022
  First merged contribution: REPLACE INTO support.
My contributions include SQL Server support, window functions, type-safe JSON traversal, MERGE queries, controlled transactions and savepoints, query cancellation, kysely-ctl, and kysely-postgres-js.
02
Zod
Schema validation with static type inference.
1. Contributor
  Nov 2022 – present
  First merged contribution: typed fatal issues.
My contributions include template literal validation, date and time checks, and BigInt validation.
03
Prisma Dev
Local Prisma Postgres for development.
1. Author
  May 2025 – Feb 2026
  Built the local Prisma Postgres development experience.
04
@prisma/studio-core
An embeddable database editor for exploring schemas, browsing data, and editing rows.
1. Author and lead
  Mar 2025 – Feb 2026
  Created the embeddable core of Prisma Studio.
05
OpenTofu
An open-source infrastructure-as-code tool.
1. Namegiver
  2023
  Coined “Tofu,” the name that became OpenTofu.

Work

I've spent most of my career in small teams, building products while the shape of the problem was still changing. I like getting close to the people who understand that problem, then having room to think through the system and build it.

At Finaloop, bank and marketplace data had to become accounting reports people could trust. I built event-driven and event-sourced pipelines, worked across different database models, and chased reconciliation gaps with accounting and fintech experts. It was distributed systems work with real business consequences, and some fixes had to ship under pressure.

At Prisma, the questions were about tools for other developers. On the experiments team, I worked on query performance insights tooling and a security product exploring bundling, RPC, and FaaS. Later, I worked on the internals of the new Studio and built prisma dev, a local development tool for Prisma Postgres. The work took me from persistence and APIs to SDKs, CLIs, and the occasional dashboard.

Random takes

Posts and replies, in my own words.

Learning in public
i do have strong opinions here and there, and i don't shy away from testing them, or my intuition/instincts about things, by stating/writing them as a way to learn/adjust if and when i get pushback. i do admit being wrong & show gratitude.
Original post Nov 2024
Tests
i think there needs to be a culture of test removal/refactor, more than simply add tests everywhere. bad tests kill velocity.
Original post Nov 2025
Testing real systems
purist hat on. the one major thing you cannot test with pglite, is transaction isolation. if you have a distributed system that relies heavily on that, you can't avoid spinning up a full-blown postgres instance. it's similar to unit tests, you cannot rely only on unit tests.
Original post May 2025
Coding agents
slop coding doesn't decrease org costs when a code review now takes waaay longer because the slop development environment is touching things for no good reason, you have to question everything, and the submitter has no recall why things were changed/added. change my mind.
Original post Mar 2025
Abstractions
people obssessing over DRY this DRY that like they've read "clean code" yesterday, need to hear this. Premature abstractions are a road full of pain, more often than not. And nope, you're not smarter than the good people that maintain the library you're about to wrap.
Original post Jun 2024
Application code
The more I got involved with library TS code, the less I wanted to do non-basic TS code in applications. A lot of people go ham with complex shit in application code to scratch an itch, they don't have an outlet.
Original post May 2023
Contracts
Return types are a must on exported functions and public class methods. Contracts are important, both for consumers and for maintenance of given functionality. Internals can be inferred or defined, depends on the complexity of the inferred type.
Original post Feb 2023
Users first
Do yourself a favor, learn SQL. It's not as hard as some authors/vendors make you believe. Optimize for app's User eXperience, not Developer eXperience (it's also important, not as important). Pick predictable tools that empower you & get out the way.
Original post Jun 2023
Hiring
when i interview people for an application-level typescript role, i wanna see application-level stuff. no wizardry. i wanna see you write some very maintainable, simple and type-safe code. ecosystem awareness. designs with extensibility in mind.
Original post Nov 2024
Judgment
be pragmatic. know when to steer and teach by example. know when to take your hands off the wheel. its about type of work and feel. don't ever lose feel.
Original post Jul 2026
Boundaries
the boundaries should always be explicitly typed and validated. this was true before agents. docs rot/drift/not tell the exact story. this was true before agents.
Original post Feb 2026
Migrations
schemas and migrations should be boring, predictable and decoupled from application code.
Original post May 2023
Package trust
trusted publishing is nice, but not enough. we need trusted maintaining, trusted process. something like `pnpm`'s `trustPolicy: no-downgrade` option but for not trusting packages with insecure repositories/processes.
Original post May 2026

Setup

Devices

Laptop: MacBook Pro 14″ · 2023 · Space Black; Apple M3 Pro · 18 GB memory · 512 GB SSD; 11-core CPU · 14-core GPU
Phone: Samsung Galaxy S25 Ultra; Titanium Black · 12 GB memory; SM-S938B/DS