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petkaantonov/bluebird

Analysis updated 2026-06-21

★ 20,526JavaScriptAudience · developerComplexity · 2/5LicenseSetup · easy

TLDR

Bluebird is a JavaScript promise library for handling async operations. Its own maintainers now recommend using native promises instead, but it remains useful for legacy browsers, old Node.js versions, or tracking down async bugs.

Mindmap

mindmap
  root((repo))
    What it does
      Promise library
      Async operations
      Legacy support
    Key Features
      Promise.map
      Warning mode
      Callback wrapping
    When to use
      Old browsers
      Legacy Node.js
      Bug detection
    Audience
      JavaScript developers
      Legacy codebases
      Node.js engineers
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filefunction / class

What do people build with it?

USE CASE 1

Add Bluebird to a legacy project that must run on Internet Explorer or old Node.js versions without stable native promises.

USE CASE 2

Use Bluebird's warning mode to find unhandled promise rejections and async bugs in an older codebase.

USE CASE 3

Migrate a callback-heavy codebase to promises step by step using Bluebird as an intermediate compatibility layer.

USE CASE 4

Use Bluebird's Promise.map to process an array of async tasks with a concurrency limit in older Node.js.

What is it built with?

JavaScript

How does it compare?

petkaantonov/bluebirdsveltejs/kitsortablejs/vue.draggable
Stars20,52620,48520,612
LanguageJavaScriptJavaScriptJavaScript
Setup difficultyeasyeasyeasy
Complexity2/53/52/5
Audiencedeveloperdeveloperdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

For new projects use native JavaScript promises instead, Bluebird is now recommended only for legacy environment support.

MIT License, use, copy, modify, and distribute freely for any purpose including commercial, with no restriction beyond keeping the copyright notice.

In plain English

Bluebird is a JavaScript promise library focused on innovative features and performance. Promises are a programming pattern for handling asynchronous operations, tasks that take time to complete, like fetching data from a server, in a cleaner, more manageable way than traditional callbacks. The library describes itself as fully featured and aimed at unmatched performance. However, its own README now prominently advises using native promises instead whenever possible, noting that native Promises have been stable in Node.js and browsers for around ten years and fast for around seven. Most utility features that Bluebird pioneered, such as a map function for processing collections, now have native equivalents in JavaScript itself and in platforms like Node.js. The maintainers currently recommend Bluebird only for projects that need to support really old browsers, end-of-life Node.js versions, or as an intermediate step for using its warnings and monitoring tools to find bugs. The library is released under the MIT License, meaning it is free to use, modify, and distribute.

Copy-paste prompts

Prompt 1
I have a Node.js 6 project using callbacks everywhere. Show me how to use Bluebird to promisify existing callback functions and refactor one module as an example.
Prompt 2
How do I use Bluebird's Promise.map with a concurrency limit to process 100 API requests in batches of 10?
Prompt 3
I want to enable Bluebird's warning mode to catch unhandled rejections in a legacy codebase. How do I configure that?
Prompt 4
What is the simplest way to replace Bluebird with native promises in a codebase that uses only .then() and .catch() with no Bluebird-specific features?

Frequently asked questions

What is bluebird?

Bluebird is a JavaScript promise library for handling async operations. Its own maintainers now recommend using native promises instead, but it remains useful for legacy browsers, old Node.js versions, or tracking down async bugs.

What language is bluebird written in?

Mainly JavaScript. The stack also includes JavaScript.

What license does bluebird use?

MIT License, use, copy, modify, and distribute freely for any purpose including commercial, with no restriction beyond keeping the copyright notice.

How hard is bluebird to set up?

Setup difficulty is rated easy, with roughly 5min to a first successful run.

Who is bluebird for?

Mainly developer.

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