Angular 4/5 - route paramMap vs params

September 2021 update

The following answer is no longer true, and the Angular team says:

There are no current plans to remove params or queryParams and there's no benefit to advising against their use.

Obsolete answer

According to the documentation :

Two older properties are still available. They are less capable than their replacements, discouraged, and may be deprecated in a future Angular version.

params — An Observable that contains the required and optional parameters specific to the route. Use paramMap instead.

Simple and efficient !

September 2021 update

The following answer is no longer true, and the Angular team says:

There are no current plans to remove params or queryParams and there's no benefit to advising against their use.

Obsolete answer

Actually there is no difference but params is pretty old and may be deprecated soon

paramMap

An Observable that contains a map of the required and optional parameters specific to the route. The map supports retrieving single and multiple values from the same parameter.

queryParamMap

An Observable that contains a map of the query parameters available to all routes. The map supports retrieving single and multiple values from the query parameter.

Note : The paramMap provide more convenience to play with route parameter. Having following three methods:

1. has()
2. get()
3. getAll()

has() :

this.router.navigate(['example', id]); 

this.activatedRoute.paramMap.subscribe(params => {
  console.log(params.has('id')); // true
})

get() :

this.router.navigate(['example', "id","another ID"]); 

this.activatedRoute.paramMap.subscribe(params => {
  console.log(params.get('id'));
})

getAll() :

this.router.navigate(['example', { foo: ['bar', 'baz'] } ]);

this.activatedRoute.paramMap.subscribe(params => {
  console.log(params.getAll('foo'));
})