Development Overview

The purpose of this document is to provide a general overview of the application architecture.

Technologies

Insomnia is a desktop application built on top of Electron. Electron provides a Chromium runtime for the Insomnia web app to run inside, as well as additional tools to provide access to operating system features.

There are a few more technologies and tools worth mentioning:

React is the library used for all UI components.
styled-components and Less are used for styling UI components.
Electron Builder is used to help build, sign, and package Insomnia for distribution.
libcurl is the library that Insomnia uses to make requests. We used libcurl as our HTTP client of choice because it allows the deepest amount of debuggability and control of HTTP requests.
NeDB a local in-memory database.
node-libcurl is a Node.js wrapper around the native libcurl library.
CodeMirror is a web-based, extendable, code editor used for highlighting and linting of data formats like JSON, GraphQL, and XML.
Commander.js is used for building the Inso CLI.

Project Structure

Insomnia uses lerna to manage multiple npm packages within a single repository. There are currently two package locations:

/packages contains related packages that are consumed by insomnia or externally.
/plugins contains plugin packages that are included by default with the application.

The `insomnia` Main Package

/packages/insomnia is the entry point for the app. All other packages are imported from this one.

There are a few notable directories inside it:

/main.development.js Entry for Electron.
/src/main Stuff that runs inside Electron's main process.
/src/ui React components and styling.
/src/common Utilities used across both main and render processes.
/src/plugins Logic around installation and usage of plugins.
/src/models DB models used to store user data.
/src/network Sending requests and performing auth (e.g. OAuth 2).
/src/templating Nunjucks and rendering related code.
/src/sync and /src/account Team sync and account stuff.

Data and State Architecture

Insomnia stores data in a few places:

A local in-memory NeDB database stores data for data models (requests, folder, workspaces, etc.).
A local Redux store contains an in-memory copy of all database entities.
Multiple React Context stores, defined in /src/ui/context.

Note: NeDB is officially unmaintained (even for critical security bugs) and was last published in February 2016. Due to this, we hope to move away from it, however doing so is tricky because of how deeply tied it is to our architecture.

Automated testing

We use Jest and react-testing-library to write our unit tests, and Playwright for integration tests.

Unit tests exist alongside the file under test. For example:

/src/common/database.js contains the database business logic
/src/common/__tests__/database.test.js contains the database tests

Unit tests for components follow the same pattern.

The structure for smoke tests is explained in the smoke testing package: packages/insomnia-smoke-test.

Technical Debt

This is just a brief summary of Insomnia's current technical debt.

Loading large responses (~20 MB) can crash the app on weaker hardware.
An in-memory duplicate of the local DB is stored in Redux.
Bundling libcurl (native module) has caused many weeks of headaches trying to get builds working across Windows, Mac, and Linux. More expertise here is definitely needed.
All input fields that support features like templating or code completion are actually CodeMirror instances. This isn't really debt, but may affect things going forward.
Use of libcurl means Insomnia can't run in a web browser and can't support bidirectional socket communication.

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