# @grpc/proto-loader > gRPC utility library for loading .proto files Latest version **0.8.1** (published 2026-05-07) · Apache-2.0 license · 0 weekly downloads ## Install ```sh npm install @grpc/proto-loader pnpm add @grpc/proto-loader yarn add @grpc/proto-loader bun add @grpc/proto-loader ``` Provides the command `proto-loader-gen-types`. ## Health **Score 60/100 (C)** — status: active. Positive: has types; no vulnerabilities; high maintenance score; high quality score. Warnings: low downloads; no esm support; pre 1.0. ## Facts | | | |---|---| | Version | 0.8.1 | | Published | 2026-05-07 | | First published | 2018-04-30 | | Weekly downloads | 0 | | License | Apache-2.0 | | TypeScript types | bundled | | Module format | CommonJS | | Node | >=6 | | Dependencies | 4 | | Unpacked size | 119.3 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 4841 | | Author | Google Inc. | | Maintainers | murgatroid99, grpc-packages, nicolasnoble | ## Links - npm: https://www.npmjs.com/package/@grpc/proto-loader - Repository: https://github.com/grpc/grpc-node - Homepage: https://grpc.io/ - Issues: https://github.com/grpc/grpc-node/issues - npm.io page: https://npm.io/package/@grpc/proto-loader ## Dependencies (4) - [long](https://npm.io/package/long.md) ^5.0.0 - [yargs](https://npm.io/package/yargs.md) ^17.7.2 - [protobufjs](https://npm.io/package/protobufjs.md) ^7.5.5 - [lodash.camelcase](https://npm.io/package/lodash.camelcase.md) ^4.3.0 ## Recent versions - 0.8.1 (latest) — 2026-05-07 - 0.7.9-pre.1 (prerelease) — 2023-07-28 - 0.6.0-pre18 (generator-draft) — 2021-03-31 - 0.8.0 — 2025-07-21 - 0.7.15 — 2025-04-18 - 0.7.14 — 2025-04-17 - 0.7.13 — 2024-05-01 - 0.7.12 — 2024-03-28 - 0.7.11 — 2024-03-26 - 0.7.10 — 2023-09-18 - 0.7.9 — 2023-08-23 - 0.7.8 — 2023-07-11 - 0.7.7 — 2023-05-03 - 0.7.6 — 2023-03-22 - 0.7.5 — 2023-02-13 - … 46 more at https://npm.io/package/@grpc/proto-loader/versions ## README # gRPC Protobuf Loader A utility package for loading `.proto` files for use with gRPC, using the latest Protobuf.js package. Please refer to [protobuf.js' documentation](https://github.com/dcodeIO/protobuf.js/blob/master/README.md) to understands its features and limitations. ## Installation ```sh npm install @grpc/proto-loader ``` ## Usage ```js const protoLoader = require('@grpc/proto-loader'); const grpcLibrary = require('grpc'); // OR const grpcLibrary = require('@grpc/grpc-js'); protoLoader.load(protoFileName, options).then(packageDefinition => { const packageObject = grpcLibrary.loadPackageDefinition(packageDefinition); }); // OR const packageDefinition = protoLoader.loadSync(protoFileName, options); const packageObject = grpcLibrary.loadPackageDefinition(packageDefinition); ``` The options parameter is an object that can have the following optional properties: | Field name | Valid values | Description |------------|--------------|------------ | `keepCase` | `true` or `false` | Preserve field names. The default is to change them to camel case. | `longs` | `String` or `Number` | The type to use to represent `long` values. Defaults to a `Long` object type. | `enums` | `String` | The type to use to represent `enum` values. Defaults to the numeric value. | `bytes` | `Array` or `String` | The type to use to represent `bytes` values. Defaults to `Buffer`. | `defaults` | `true` or `false` | Set default values on output objects. Defaults to `false`. | `arrays` | `true` or `false` | Set empty arrays for missing array values even if `defaults` is `false` Defaults to `false`. | `objects` | `true` or `false` | Set empty objects for missing object values even if `defaults` is `false` Defaults to `false`. | `oneofs` | `true` or `false` | Set virtual oneof properties to the present field's name. Defaults to `false`. | `json` | `true` or `false` | Represent `Infinity` and `NaN` as strings in `float` fields, and automatically decode `google.protobuf.Any` values. Defaults to `false` | `includeDirs` | An array of strings | A list of search paths for imported `.proto` files. The following options object closely approximates the existing behavior of `grpc.load`: ```js const options = { keepCase: true, longs: String, enums: String, defaults: true, oneofs: true } ``` ## Generating TypeScript types The `proto-loader-gen-types` script distributed with this package can be used to generate TypeScript type information for the objects loaded at runtime. More information about how to use it can be found in [the *@grpc/proto-loader TypeScript Type Generator CLI Tool* proposal document](https://github.com/grpc/proposal/blob/master/L70-node-proto-loader-type-generator.md). The arguments mostly match the `load` function's options; the full usage information is as follows: ```console proto-loader-gen-types.js [options] filenames... Options: --help Show help [boolean] --version Show version number [boolean] --keepCase Preserve the case of field names [boolean] [default: false] --longs The type that should be used to output 64 bit integer values. Can be String, Number [string] [default: "Long"] --enums The type that should be used to output enum fields. Can be String [string] [default: "number"] --bytes The type that should be used to output bytes fields. Can be String, Array [string] [default: "Buffer"] --defaults Output default values for omitted fields [boolean] [default: false] --arrays Output default values for omitted repeated fields even if --defaults is not set [boolean] [default: false] --objects Output default values for omitted message fields even if --defaults is not set [boolean] [default: false] --oneofs Output virtual oneof fields set to the present field's name [boolean] [default: false] --json Represent Infinity and NaN as strings in float fields. Also decode google.protobuf.Any automatically [boolean] [default: false] --includeComments Generate doc comments from comments in the original files [boolean] [default: false] -I, --includeDirs Directories to search for included files [array] -O, --outDir Directory in which to output files [string] [required] --grpcLib The gRPC implementation library that these types will be used with. If not provided, some types will not be generated [string] --inputTemplate Template for mapping input or "permissive" type names [string] [default: "%s"] --outputTemplate Template for mapping output or "restricted" type names [string] [default: "%s__Output"] --inputBranded Output property for branded type for "permissive" types with fullName of the Message as its value [boolean] [default: false] --outputBranded Output property for branded type for "restricted" types with fullName of the Message as its value [boolean] [default: false] --targetFileExtension File extension for generated files. [string] [default: ".ts"] --importFileExtension File extension for import specifiers in generated code. [string] [default: ""] ``` ### Example Usage Generate the types: ```sh $(npm bin)/proto-loader-gen-types --longs=String --enums=String --defaults --oneofs --grpcLib=@grpc/grpc-js --outDir=proto/ proto/*.proto ``` Consume the types: ```ts import * as grpc from '@grpc/grpc-js'; import * as protoLoader from '@grpc/proto-loader'; import type { ProtoGrpcType } from './proto/example.ts'; import type { ExampleHandlers } from './proto/example_package/Example.ts'; const exampleServer: ExampleHandlers = { // server handlers implementation... }; const packageDefinition = protoLoader.loadSync('./proto/example.proto'); const proto = (grpc.loadPackageDefinition( packageDefinition ) as unknown) as ProtoGrpcType; const server = new grpc.Server(); server.addService(proto.example_package.Example.service, exampleServer); ``` --- _Source: https://npm.io/package/@grpc/proto-loader · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._