At some point, most growing startups end up maintaining more than one codebase that shares logic: a marketing site and a product app that share a design system, a web app and a mobile app that share business logic, or a public product and an internal admin panel that share the same API client. Managing that shared code across separate repositories works fine at first, and then quietly becomes one of the most common sources of engineering friction as the team grows.
A monorepo, a single repository holding multiple projects and shared packages, is one answer to that problem, and in 2026 the tooling for doing this well has matured considerably. Two tools dominate the conversation for JavaScript and TypeScript teams: Turborepo and Nx. Both solve a similar core problem, running builds, tests, and lint checks efficiently across many packages, but they take different approaches, and picking the wrong one for your team's stage can cost weeks of unnecessary configuration work.
In a multi-repo setup, sharing code between projects usually means publishing an internal package, versioning it, and having each consuming project install and upgrade it independently. That process works, but it adds real friction: a small fix to a shared UI component means publishing a new version, then going into each consuming repo to bump the dependency, open a PR, and wait for CI, before the fix actually reaches users anywhere.
As the number of shared packages grows, this coordination overhead grows with it. Teams often notice the pain first in design system changes, where a single button component used across three apps needs its update propagated everywhere, and the propagation lag itself becomes a recurring source of visual inconsistency and duplicated bug fixes.
Picture a startup running a customer-facing web app, an internal admin dashboard, and a shared component library used by both. In a multi-repo setup, updating the component library requires publishing a new package version and then manually bumping it in two other repositories, each with its own CI pipeline and review process, before the change is live anywhere.
In a monorepo with Turborepo or Nx, that same component library lives as a workspace package alongside the two apps. A change to a shared button component is committed once, and both the web app and the admin dashboard can consume it immediately in local development, with the build system only rebuilding the packages actually affected by the change, not the entire codebase. This is the core value proposition: faster iteration on shared code without publishing overhead, and build systems smart enough to avoid rebuilding what has not changed.
A monorepo is not automatically the right choice for every team. If your projects genuinely do not share code, or if different projects need to move on completely independent release schedules with different ownership boundaries, a monorepo can add structural overhead without a matching benefit. It is worth revisiting this decision alongside broader questions covered in our guide to building an internal developer platform, since monorepo tooling is really one piece of a team's overall developer experience strategy, not a standalone decision.
It is also worth pairing any monorepo migration with a hard look at your existing CI/CD pipeline setup, since a monorepo's benefits depend heavily on your pipeline being configured to run only affected tasks rather than the entire suite on every change. Skipping that step is the most common reason teams find their monorepo migration disappointing rather than the productivity win they expected.
A monorepo does not remove the need for good engineering discipline, it changes where that discipline needs to live, moving from cross-repo coordination to within-repo task orchestration.
One concern teams raise before moving to a monorepo is ownership: if everything lives in one place, how do you keep one team's changes from accidentally breaking another team's app? Both Turborepo and Nx support this through code ownership files and per-package configuration, so you can still require specific reviewers for changes to a given package, and CI can be configured to only run checks relevant to what actually changed. The dependency graph both tools generate also makes it much easier to see, before merging, exactly which downstream apps a given change could affect, something that is genuinely hard to know for certain in a multi-repo setup where those dependencies are implicit.
Access control questions come up more often for larger organizations than early-stage startups, since a five-person engineering team rarely needs to restrict internal visibility between its own projects. It becomes more relevant once a startup grows past a single engineering pod and starts having teams that own distinct product areas, at which point the same monorepo tooling that sped up small-team iteration needs a bit more structure layered on top to keep ownership boundaries clear.
Teams often underestimate how much of a monorepo migration is build configuration rather than moving files. Moving repository history and updating import paths is usually the fast part, often finishable within days for a handful of related projects. The slower part is tuning the task pipeline: defining which tasks depend on which, getting caching to actually produce cache hits instead of silently missing due to inconsistent environment variables or file hashing quirks, and adjusting CI to only run affected tasks.
For example, a startup migrating three related repositories into a monorepo might reasonably budget a focused sprint for the initial move and workspace setup, then expect another week or two of iteration on caching and CI configuration before the setup feels genuinely fast rather than just consolidated. Rushing past that second phase is the most common reason a team ends up with a monorepo that is organizationally tidier but not meaningfully faster to work in day to day.
Turborepo and Nx both solve the same underlying problem for startups: making a growing codebase of shared packages and multiple apps fast to build, test, and iterate on. Turborepo suits teams that want speed with minimal configuration, while Nx suits teams anticipating more scale and structure. The right choice depends less on which tool is objectively better and more on how much shared code your team actually has today, and how quickly that is likely to grow. Startups working with our web development team often make this call as part of a broader architecture review rather than as an isolated tooling decision.