LoopBack makes it easy to build modern applications that require complex integrations.

• Fast, small, powerful, extensible core
• Generate real APIs with a single command
• Define your data and endpoints with OpenAPI
• No maintenance of generated code

Status: General Availability

LoopBack 4 GA (General Availability) has been released in October 2018, read more in the announcement post.

The documentation website is https://loopback.io/doc/en/lb4/.

Learn about the latest and greatest features and technologies in LoopBack 4 by using it for your next project. Start by having a look at Getting Started.

Check the API documentation for all the API usages in each package.

Long Term Support

We don't provide any LTS version for LoopBack 4 yet. Please join the discussion in loopback-next#4398 if you are interested in a version that's less frequently changed.

Please refer to our Long Term Support Policy for more details.

Installation

Make sure you have the following installed:

You can generate a project with our generator or with the CLI as follows:

npm create loopback
npx -p @loopback/cli lb app

To create your first LoopBack 4 application, see Getting Started.

Documentation

• Official documentation
• API documentation
• FAQ
• LoopBack 3 vs LoopBack 4
• Tutorials
• Examples

Contributing

See the following resources to get you started:

• Contributing Guidelines
• Monorepo overview
• Developing LoopBack

You can join the team by posting a comment to issue #110.

Security

If you think you have discovered a new security issue with any LoopBack package, please do not report it on GitHub. Instead, send an email to security@loopback.io with a full description and steps to reproduce.

See SECURITY.md for more details.

Team

Project Architect

Raymond Feng

Technical Steering Committee

Raymond Feng	Diana Lau	Mario Estrada	Rifa Achrinza	Francisco Buceta	Samarpan Bhattacharya

Other Project Maintainers

Nora Abdelgadir	Matthew Schnee	Hage Yaapa
Agnes Lin	Madaky	Hugo Da Roit
Nico Flaig	Denny Bartelt	Douglas McConnachie
Samarpan Bhattacharya	Muhammad Aaqil

See all contributors.

Alumni

• @ritch
• @superkhau
• @rashmihunt
• @kjdelisle
• @virkt25
• @shimks
• @b-admike
• @deepakrkris
• @bajtos
• @jannyhou
• @emonddr

License

MIT

Change Log

All notable changes to this project will be documented in this file. See Conventional Commits for commit guidelines.

15.0.5 (2025-01-15)

Note: Version bump only for package @loopback/eslint-config

15.0.4 (2024-08-14)

Note: Version bump only for package @loopback/eslint-config

15.0.3 (2024-06-10)

Note: Version bump only for package @loopback/eslint-config

15.0.2 (2024-05-17)

Note: Version bump only for package @loopback/eslint-config

15.0.1 (2024-04-09)

Note: Version bump only for package @loopback/eslint-config

15.0.0 (2024-03-04)

Bug Fixes

• import naming convention lint (acd3c0c), closes /github.com/typescript-eslint/typescript-eslint/pull/7269#issuecomment-1777628591

chore

• drop Node.js 16 support (b9efcb4)

BREAKING CHANGES

• Drop Node.js 16 support in all LB4 modules and extensions

Signed-off-by: dhmlau dhmlau@ca.ibm.com

14.0.5 (2023-12-12)

Note: Version bump only for package @loopback/eslint-config

14.0.4 (2023-09-12)

Note: Version bump only for package @loopback/eslint-config

14.0.3 (2023-08-15)

Note: Version bump only for package @loopback/eslint-config

14.0.2 (2023-07-17)

Note: Version bump only for package @loopback/eslint-config

14.0.1 (2023-06-28)

Note: Version bump only for package @loopback/eslint-config

14.0.0 (2023-05-15)

Features

• add support for node v20 (e23cefa)
• remove support for node v14 (5425762)
• remove support for node v19 (e26a2ac)

BREAKING CHANGES

• End of life of Node v14

Signed-off-by: Francisco Buceta frbuceta@gmail.com

13.0.10 (2023-04-13)

Bug Fixes

• refresh package lock files (9979eb1), closes #9351

13.0.9 (2023-03-09)

Note: Version bump only for package @loopback/eslint-config

13.0.8 (2023-02-07)

Bug Fixes

• disable strictNullChecks check for prefer-nullish-coalescing rule (abd6469)

13.0.7 (2023-01-09)

Note: Version bump only for package @loopback/eslint-config

Change Log

All notable changes to this project will be documented in this file. See Conventional Commits for commit guidelines.

13.0.6 (2022-12-14)

Note: Version bump only for package @loopback/eslint-config

Change Log

All notable changes to this project will be documented in this file. See Conventional Commits for commit guidelines.

13.0.5 (2022-11-24)

Note: Version bump only for package @loopback/eslint-config

Change Log

All notable changes to this project will be documented in this file. See Conventional Commits for commit guidelines.

13.0.4 (2022-10-13)

Note: Version bump only for package @loopback/eslint-config

13.0.3 (2022-08-25)

Note: Version bump only for package @loopback/eslint-config

13.0.2 (2022-07-14)

Note: Version bump only for package @loopback/eslint-config

13.0.1 (2022-06-13)

Bug Fixes

• revert update and pin version of eslint-plugin-mocha to v10.0.3 (19b3ac3)

13.0.0 (2022-05-05)

⚠ BREAKING CHANGES

• remove node v12 support

Features

• add support for node v18 (ccb4c61)
• remove node v12 support (5f66e5b)

Reverts

• update dependency eslint-plugin-mocha to ^10.0.4 (c7f9263)

12.0.4 (2022-03-29)

Bug Fixes

• ignore HTTP code-like object members (493e275)
• ignore MIME type-like object members (f282dca)

12.0.3 (2022-02-28)

Note: Version bump only for package @loopback/eslint-config

12.0.2 (2022-02-14)

Note: Version bump only for package @loopback/eslint-config

12.0.1 (2022-01-11)

Note: Version bump only for package @loopback/eslint-config

12.0.0 (2021-11-18)

Features

• drop support for Node.js v10 (9bcbbb3)
• support Node.js v17 (8d86c03)
• upgrade to TypeScript 4.5.2 (72ece91)

BREAKING CHANGES

• drop support for Node.js v10

Co-authored-by: Francisco Buceta frbuceta@gmail.com Signed-off-by: Rifa Achrinza 25147899+achrinza@users.noreply.github.com

11.0.2 (2021-10-18)

Note: Version bump only for package @loopback/eslint-config

11.0.1 (2021-09-16)

Note: Version bump only for package @loopback/eslint-config

11.0.0 (2021-07-15)

Features

• rest: upgrade to ajv@8.x (d3b20ed)

BREAKING CHANGES

• rest: We upgrade to ajv@8.x, which contains breaking changes for validations. See https://github.com/ajv-validator/ajv/blob/master/docs/v6-to-v8-migration.md.

Signed-off-by: Raymond Feng enjoyjava@gmail.com

10.2.1 (2021-06-10)

Note: Version bump only for package @loopback/eslint-config

10.2.0 (2021-05-03)

Features

• support node v16 (ac99415)

10.1.1 (2021-04-06)

Note: Version bump only for package @loopback/eslint-config

10.1.0 (2021-03-18)

Bug Fixes

• no need to import prettier extensions anymore (0b13d35)

Features

• update package-lock.json to v2 consistently (dfc3fbd)
• upgrade to TypeScript 4.2.x (05930bc)

10.0.5 (2021-01-21)

Note: Version bump only for package @loopback/eslint-config

10.0.4 (2020-12-07)

Note: Version bump only for package @loopback/eslint-config

10.0.3 (2020-11-18)

Note: Version bump only for package @loopback/eslint-config

10.0.2 (2020-11-05)

Note: Version bump only for package @loopback/eslint-config

10.0.1 (2020-10-07)

Note: Version bump only for package @loopback/eslint-config

10.0.0 (2020-09-15)

Features

• eslint-config: update rules to be compatible with typescript-eslint 4.x (595951c)
• update typescript-eslint monorepo to v4 (5767e22)

BREAKING CHANGES

• eslint-config: typescript-eslint 4.x introduces some breaking changes. The following are impacted:

• decorator functions are correctly honored as usage of defined variables

• @typescript-eslint/no-shadow replaces no-shadow

Signed-off-by: Raymond Feng enjoyjava@gmail.com

9.0.2 (2020-08-27)

Note: Version bump only for package @loopback/eslint-config

9.0.1 (2020-08-19)

Note: Version bump only for package @loopback/eslint-config

9.0.0 (2020-08-05)

Features

• eslint-config: disable createDefaultProgram (13dbaf2)

BREAKING CHANGES

• eslint-config: We are no longer telling eslint to create a default program for files not included in tsconfig.json. If you start receiving linter errors after upgrade, you can either add createDefaultProgram to your eslint config manually, modify your tsconfig file to include all files checked by eslint, or exclude the problematic files from linting by adding them to .eslintignore file.

In projects scaffolded via lb4 app, we recommend to add .eslintrc.js file to .eslintignore list.

Signed-off-by: Miroslav Bajtoš mbajtoss@gmail.com

8.0.4 (2020-07-20)

Note: Version bump only for package @loopback/eslint-config

8.0.3 (2020-06-30)

Note: Version bump only for package @loopback/eslint-config

8.0.2 (2020-06-23)

Bug Fixes

• set node version to >=10.16 to support events.once (e39da1c)

8.0.1 (2020-06-11)

Note: Version bump only for package @loopback/eslint-config

8.0.0 (2020-05-28)

Features

• eslint-config: add naming convention rules (c8e2143)
• eslint-config: disable 'warning Missing return type on function' for now (1b3494e)

BREAKING CHANGES

• eslint-config: @typescript-eslint/typescript-eslint v3.0.0 introduces a list of breaking changes. Existing code might violate the new or changed rules. Manual fixes may be required.

See more details at: https://github.com/typescript-eslint/typescript-eslint/releases/tag/v3.0.0

7.0.1 (2020-05-20)

Note: Version bump only for package @loopback/eslint-config

7.0.0 (2020-05-19)

Features

• replace eslint rule no-invalid-this with TypeScript-aware one (b2f21f7)
• eslint-config: upgrade to ESLint 7.x (5c3e3c2)

BREAKING CHANGES

• In code accessing this variable, eslint-ignore comment for no-invalid-this will no longer work. You can either change those comments to disable @typescript-eslint/no-invalid-this, or better tell TypeScript what is the type of this in your function.

A TypeScript example:

describe('my mocha suite', function (this: Mocha.Suite) {
  this.timeout(1000);
  it('is slow', function (this: Mocha.Context) {
    this.timeout(2000);
  });
});

A JavaScript example:

describe('my mocha suite', /** @this {Mocha.Suite} */ function () {
  this.timeout(1000);
  it('is slow', /** @this {Mocha.Context} */ function () {
    this.timeout(2000);
  });
});

Signed-off-by: Miroslav Bajtoš mbajtoss@gmail.com

• eslint-config: ESLint 7.x changes how plugins references in the shared config are resolved. The following is quoted from https://eslint.org/blog/2020/05/eslint-v7.0.0-released:

ESLint will now resolve plugins relative to the entry configuration file. This means that shared configuration files that are located outside the project can now be colocated with the plugins they require. Starting in ESLint v7, configuration files and ignore files passed to ESLint using the --config path/to/a-config and --ignore-path path/to/a-ignore CLI flags, respectively, will resolve from the current working directory rather than the file location. This allows for users to utilize shared plugins without having to install them directly in their project.

6.0.6 (2020-05-07)

Note: Version bump only for package @loopback/eslint-config

6.0.5 (2020-04-29)

Note: Version bump only for package @loopback/eslint-config

6.0.4 (2020-04-22)

Note: Version bump only for package @loopback/eslint-config

6.0.3 (2020-04-08)

Note: Version bump only for package @loopback/eslint-config

6.0.2 (2020-03-24)

Note: Version bump only for package @loopback/eslint-config

6.0.1 (2020-03-17)

Note: Version bump only for package @loopback/eslint-config

6.0.0 (2020-03-05)

chore

• remove support for Node.js v8.x (4281d9d)

Features

• eslint-config: disallow non-null assertions after optional chain (6fdc2b5), closes #4675

BREAKING CHANGES

• eslint-config: eslint rule @typescript-eslint/no-non-null-asserted-optional-chain is set to error which may break existing lint tests.
• Node.js v8.x is now end of life. Please upgrade to version 10 and above. See https://nodejs.org/en/about/releases.

5.0.3 (2020-02-05)

Note: Version bump only for package @loopback/eslint-config

5.0.2 (2020-01-27)

Note: Version bump only for package @loopback/eslint-config

5.0.1 (2020-01-07)

Note: Version bump only for package @loopback/eslint-config

5.0.0 (2019-12-09)

Features

• eslint-config: add @typescript-eslint/prefer-nullish-coalescing rule (b608120)
• eslint-config: add typescript-eslint/prefer-optional-chain rule (bd1252a)
• eslint-config: enable no-extra-non-null-assertion (d74a688)
• eslint-config: enable return-await (be6b38b)

BREAKING CHANGES

• eslint-config: The linter will reject code using return await ouside of try blocks or forgetting to await before returning from inside a try block. Migration guide: use return outside of try blocks and return await inside try blocks.

Signed-off-by: Miroslav Bajtoš mbajtoss@gmail.com

• eslint-config: the @typescript-eslint/prefer-nullish-coalescing rule prefers nullish coalescing, for example, ttl ?? 5000 over ttl || 5000.

See https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#nullish-coalescing

• eslint-config: the @typescript-eslint/prefer-optional-chain rule will report violations if optional chaining is not used. For example, it prefers options?.ttl over options && options.ttl.

See https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#optional-chaining

4.1.5 (2019-11-25)

Note: Version bump only for package @loopback/eslint-config

4.1.4 (2019-11-12)

Note: Version bump only for package @loopback/eslint-config

4.1.3 (2019-10-24)

Note: Version bump only for package @loopback/eslint-config

4.1.2 (2019-10-07)

Note: Version bump only for package @loopback/eslint-config

4.1.1 (2019-09-27)

Note: Version bump only for package @loopback/eslint-config

4.1.0 (2019-09-17)

Features

• eslint-config: enable "no-misused-promises" rule (88d5494)

4.0.2 (2019-09-03)

Note: Version bump only for package @loopback/eslint-config

4.0.1 (2019-08-19)

Note: Version bump only for package @loopback/eslint-config

4.0.0 (2019-08-15)

Features

• eslint-config: upgrade to @typescript-eslint/eslint-plugin 2.0.0 (1ec5b2f)

BREAKING CHANGES

• eslint-config: @typescript-eslint/parser and @typescript-eslint/eslint-plugin 2.0.0 may have introduced breaking changes for recommended rules and configuration

3.0.0 (2019-07-31)

Features

• eslint-config: enable "no-return-await" rule (e28a3c3)

BREAKING CHANGES

• eslint-config: "return await" is no longer allowed, just return the promise without awaiting its resolution.

2.0.2 (2019-07-26)

Note: Version bump only for package @loopback/eslint-config

2.0.1 (2019-07-17)

Note: Version bump only for package @loopback/eslint-config

2.0.0 (2019-06-28)

Features

• eslint-config: enable "no-floating-promises" rule (256e3e8)
• eslint-config: upgrade eslint to v6 (b52a40c)

BREAKING CHANGES

• eslint-config: We require eslint version 6.0 as a peer dependency now. To upgrade your project using our eslint-config, bump up eslint version in your package.json file to "^6.0.0".

The new eslint version added new recommended rules, most notably "require-atomic-updates" and "no-prototype-builtins". You may get new linting errors after upgrade, fix them by changing your code or adding eslint-ignore comments as needed.

1.1.2 (2019-06-17)

Note: Version bump only for package @loopback/eslint-config

1.1.1 (2019-06-06)

Note: Version bump only for package @loopback/eslint-config

1.1.0 (2019-06-03)

Features

• replace tslint with eslint (44185a7)
• eslint-config: allow detection of tsconfig file (5c16db6)

1.0.0-3 (2019-05-31)

Note: Version bump only for package @loopback/eslint-config

1.0.0-2 (2019-05-30)

Features

• build: add eslint scripts and default configs (a6abe86)