How do you set a default version so unversioned requests are handled by a specific version in NestJS?

Q: How do you set a default version so unversioned requests are handled by a specific version in NestJS?

// Header versioning with default version app.enableVersioning({ type: VersioningType.HEADER, header: 'X-API-Version', defaultVersion: '1', // treat requests without the header as v1 }); // URI versioning with default version app.enableVersioning({ type: VersioningType.URI, defaultVersion: '1', // GET /users (no /v1 prefix) -> v1 controller }); // Multiple default versions — try each in order app.enableVersioning({ type: VersioningType.URI, defaultVersion: ['1', '2'], }); // VERSION_NEUTRAL routes always match — ignores defaultVersion entirely import { VERSION_NEUTRAL } from '@nestjs/common'; @Version(VERSION_NEUTRAL) @Get('health') healthCheck() { return { status: 'ok' }; } // GET /health always matches — no version header or prefix needed defaultVersion prevents breaking existing clients during a migration to versioned APIs. Clients that send no version header or prefix receive the default version's responses transparently. VERSION_NEUTRAL routes bypass the defaultVersion setting — they match regardless of version context. Set defaultVersion to the latest stable version once all clients have been migrated. Passing an array to defaultVersion tries each in order — useful when two versions are considered current.

Difficulty: 5/10

API versioning, NestJS configuration, Routing fallback

Pass a defaultVersion option to app.enableVersioning(). Unversioned requests — those without a version prefix or header — are routed to the default version's handlers. This is useful during migrations when existing clients do not yet send a version identifier. VERSION_NEUTRAL routes always match regardless of defaultVersion.

Setting a default version for unversioned requests

Default version use cases:

1
defaultVersion prevents breaking existing clients during a migration to versioned APIs.
2
Clients that send no version header or prefix receive the default version's responses transparently.
3
VERSION_NEUTRAL routes bypass the defaultVersion setting — they match regardless of version context.
4
Set defaultVersion to the latest stable version once all clients have been migrated.
5
Passing an array to defaultVersion tries each in order — useful when two versions are considered current.

Scenario Questions

0-2 years experience

How do you set a default version so unversioned requests are handled by a specific version in NestJS?

Scenario Questions

Follow-up Questions