Possessing certified skills is essential in today's knowledge economies. For most, these can be acquired through the standard route i.e. a period spent in a learning environment followed by an assessment. This standard path, however, may be unsuitable for many vulnerable groups. These include individuals who have learned a job through practical experience or those who have earned a non-recognized foreign degree. Possessing skills that are not certified by a recognized credential is arguably a major source of disadvantage. To deal with this issue, interest in alternative paths to skill credentials has been rapidly gaining ground. The concrete tools and policies deployed are known as alternative credentials. Examples include processes allowing for the recognition of prior learning (RPL) which provide the certification of skills gained through practical experience, the recognition of foreign degrees, the modularisation of standard VET or adult education programmes, which allow individuals to obtain partial certification without the need to complete a full programme. Against this background, the objective of this paper is to identify and discuss the psychological and social policy implications of alternative credentials. We argue that the distributional impact of these credentials is not predetermined. Drawing on insights from life course research, we identify two key dimensions likely to shape the distributional impact of alternative credentials. First, the degree to which these alternative credentials are cumulable and can provide access to standard educational and training offers (or "stackability"). Second, the extent to which such credentials are known to and recognised as valuable by employers. Intersecting these two dimensions, we develop a typology which we illustrate with examples taken from various European countries.