Understanding Monorepos: What you need to know Benjamin Cabanes & Philip Fulcher Monorepos are hot right now, especially among Web developers. We’re here to help you understand what they are, what problems they solve, and how Nx makes them delightful. You can break down barriers and reclaim the collaboration you’ve been missing.

1. Understanding
monorepos
@PhilipJFulcher
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2. Hi 👋
I’m Benjamin Cabanes
🇨🇦 · 🐬
Javascript Architect @ Nrwl
Nx Core Team
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3. Hi 👋
I’m Philip Fulcher
🇺🇸 · 🐬
Nx Core Team Member
@philipjfulcher
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4. Why do companies
use monorepos?
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5. SHORT
ANSWER?
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6. Why do companies use
monorepos?
• Manage complexity
• Organization-wide best
practices
• Maximizing shared code
• Consistency & predictability in
code
• Discoverability and
communication
• Foster collaboration
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7. LONG
ANSWER?
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8. Let’s talk about
monorepos…
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9. What is a
monorepo?
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10. A monorepo is a single repository
containing multiple distinct projects,
with well-de
fi
ned relationships.
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11. A monorepo is a single repository
containing multiple distinct projects,
with well-de
fi
ned relationships.
@PhilipJFulcher
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12. A monorepo is a single repository
containing multiple distinct projects,
with well-de
fi
ned relationships.
@PhilipJFulcher
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13. @PhilipJFulcher
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14. You projects in the
same place
• High level view of projects
• Allows collaboration
• Removes assumptions
• Project discoverability
• Code reuse
• Architecture discoverability
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15. @PhilipJFulcher
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16. ✋ Monolith ≠ Monorepo ✋
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17. Monolith & Monorepo are different concepts
A monorepo is about code organization
A monolith is about code linking and particular type of deployment
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18. @PhilipJFulcher
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19. A monorepo is a single repository
containing multiple distinct projects,
with well-de
fi
ned relationships.
@PhilipJFulcher
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20. Well-de
fi
ned relationships are
used by tooling to provide
automation & assistance
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21. 00
V1
Date
Presentation Subtitle
Presentation Title
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22. Cross-project changes
Architecture awareness
Relationships
are key
Performance with
smart commands
Project graph
Projects discoverability & always
up to date visual representation
Test/build only affected code
Identify relations & contracts
Smart code generation
Adds a smart layer to
project relationships
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23. Smarter tooling
Better DX
Collaboration & Productivity increase
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24. Wait. So what’s wrong
with my polyrepo setup? 🤔
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25. Well, nothing is really
*wrong*. It’s just…
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26. Polyrepos have a high
cost of maintenance.
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27. Polyrepos are dif
fi
cult
to scale.
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28. A common situation
with polyrepos
Let’s share
some code!
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29. Sharing code with
polyrepos
4/ Write the shareable code
5/ CI & CD checks
6/ Deploy & publish to registry
1/ Create repository, setting
permissions, team management
2/ Setup CI & CD (waiting from
IT team)
3/ Setup tooling for build, serve,
lint …
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30. - Write the shared code
Sharing code with
monorepos
- Test consuming projects
directly from where you are.
All changes are done in a single PR
Consumers are all tested (high con
fi
dence)
No externals, faster merge and release
- Use existing code, tooling
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31. Sharing code with
polyrepos
- depends on published artefacts
- Changes, PRs, Code reviews, CI/
CD runs times “n” for each repo
- Takes time to complete and
start using the shared code.
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32. Sharing code with
polyrepos
A: v1.0
B: v1.0 C: v1.0
D: v1.0
A: v1.0
B: v1.0 C: v1.1
B: v1.0 C: v1.1
A: v1.0
B: v1.0 C: v1.1
D: v1.0 D: v1.1
😨
😎 😱
💎The Diam
on
d Dependency Problem 💎
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33. Polyrepos creates silos &
makes collaboration
harder.
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34. It is easy to do the wrong
things when working in
silos.
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35. Polyrepos and monoliths
are pretty common.
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36. @PhilipJFulcher
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37. The industry has moved to the
polyrepo to get team autonomy.
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38. Autonomy by isolation
harms collaboration.
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39. What about
monorepos then?
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40. Monorepos do
relationships analysis
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41. One version of everything
03
Atomic commit across projects
02
No overhead to create new projects
01
Developer mobility
05
Consistent tooling
04
Monorepos
bene
fi
ts
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42. I can’t use a monorepo.
I do micro frontends. 😏
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43. Again, a common
misconception.
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44. No more assumptions,
all the code is here,
easier to debug with monorepos
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45. A monorepo makes micro-
frontends easier & manageable
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46. If everyone has access to
everything. Then it’s
unmanageable. Right? 😱
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47. Again, a common
misconception.
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48. Polyrepo
code ownership?
No high level overview
No structure
Everyone can depend on everything
Permissions per repository
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49. Monorepo
code ownership
High level overview
Visible structure & enforced by tooling
Clear hierarchy and dependencies
Granular access:
- constraints per import
- constraints per folder
- constraints per project
- custom constraints with tooling
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50. Relationships are key to
monorepos
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51. 00
V1
Date
Presentation Subtitle
Presentation Title

52. Why is Nx the right
tool for your
Monorepo?
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53. Not just code
colocation
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54. Projects
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55. Knowledge Base
feat-knowledge-base
Live Chat
feat-live-chat
Support Tickets
feat-support-tickets
New Ticket
feat-new-ticket
Libraries
Customer Service App
App
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56. - Name
- Path Alias
- Well-de
fi
ned API
Each project
has
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57. cart-ui-components
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58. @myorg/cart/ui-components
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59. @PhilipJFulcher
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60. Well-De
fi
ned
Relationships
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61. Tags
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62. Module
Boundaries
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63. Microfrontends 😎
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64. Superpowered
Micro Frontends with
Monorepos
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65. Speeding up day-to-
day development
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66. Targets
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67. Testing
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68. Affected Commands
- affected:test
- affected:build
- affected:e2e
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69. Never run the same target
twice.
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70. Nx Cloud
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71. Into the (Nx) Clouds
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72. Atomic Changes
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73. Project
Graph
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74. Affected Commands
- affected:test
- affected:build
- affected:e2e
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75. Experimentation
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76. Generators
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77. Workspace Generators
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78. Keys take away on
monorepos
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79. Monorepos are not just about
code colocation
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80. Well-de
fi
ned relationships between
isolated units of code are essential
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81. Good tools & automation are needed for
a monorepo to scale with the
organization
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82. nx.dev
monorepo.tools
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