# \[ANN\] Impostor.jl - A highly versatile synthetic data generator

**URL:** <https://discourse.julialang.org/t/ann-impostor-jl-a-highly-versatile-synthetic-data-generator/106166>\
**Category:** Package Announcements\
**Tags:** package, announcement, dataframes\
**Created:** [November 13, 2023, 10:31pm UTC](https://discourse.julialang.org/t/ann-impostor-jl-a-highly-versatile-synthetic-data-generator/106166 "2023-11-13T22:31:25Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![lfenzo](https://avatars.discourse-cdn.com/v4/letter/l/85e7bf/32.png) [@lfenzo](https://discourse.julialang.org/u/lfenzo)\
**Post date:** [November 14, 2023, 1:11am UTC](https://discourse.julialang.org/t/ann-impostor-jl-a-highly-versatile-synthetic-data-generator/106166/3 "2023-11-14T01:11:00Z")

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Thanks for the question, @juliohm!

Impostor.jl differs from Faker.jl in various aspects, I’ll break down these differences into client-side and backend so we can better address them.

- **Client-Side:**
  - Generator functions exported by Impostor.jl adhere to the Julia’s multiple dispatch paradigm in order to expand their functionality by adding more options to control how data series are generated. This is a convention established across the API to which virtually all generator functions exported by Impostor adhere; such level of control is not available in Faker.jl. This is more thoroughly explained in the [Concepts](https://lfenzo.github.io/Impostor.jl/stable/#Concepts) section in the docs.
  - The templating functionality provided by Faker.jl is improved in Impostor.jl by the addition of relations between the columns in the notion of _hierarchical_ data. That is, data generated by the `ImpostorTemplate` is expected to respect certain properties found in real data; an example of that is the set of relations between countries, states and cities in which some cities can only be associated to certain countries and so on. The provided `my_custom_template` in the first post is another example of such situation (notice the interactions between the `country_code`, `state` and `city` columns). Impostor. was designed in such way that these _hierarchical restrictions_ can be incorporated in other providers in the future using the current backend organization.
  - The utility functionalities in Impostor.jl are much more condensed than in Faker.jl in terms of methods to interact with. For example, in Faker functions like `lexify`, `numerify`, `bothify`, `random_lowercase_letter`, `random_uppercase_letter`, `random_digit` and `random_number` are all centered around the `render_alphanumeric` function to render string templates.
  - Although both Impostor.jl and Faker.jl support the assignment of locales to the current session, locales in Impostor.jl can be specified on a per-method call basis and both the session and methods have multi-locale support.

- **Backend:**
  - Data in Impostor.jl is stored in partitioned `.csv` files and on-demand loaded according to the needs in the current session by each one of the _generator_ functions. This decision comes from the fact that `.csv` files are faster parse than the `.yaml`s in Faker.jl and occupy potentially less space in disk. In Impostorl.jl, only the necessary data is loaded when a _generator_ function is called, the sections [Design and Structure](https://lfenzo.github.io/Impostor.jl/stable/developer_guide/quick_tour/#Design-and-Structure) and [Archive Organization](https://lfenzo.github.io/Impostor.jl/stable/developer_guide/quick_tour/#Archive-Organization) present further details on these topics.
  - Virtually all data manipulation takes place as `DataFrame` operations, this eases implementation of other _generator_ functions by other contributors as it removes the boilerplate when relating different datasets present in Impostor’s Data Archive.

In summary, Impostor.jl is an improved version of Faker.jl, designed from the ground up to be maintainable, versatile and more efficient when it comes to generating tabular data. At the moment, the current selection of providers is not as complete as Faker’s, but in the future and with community input, the plans are to vastly expand this collection.

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