Open Access and Article Processing Charge (APC)

All articles published in Challenges (ISSN 2078-1547) are published in full open access. An article processing charge (APC) of CHF 1400 (Swiss francs) applies to papers accepted after peer review. This article processing charge is to cover the costs of peer review, copyediting, typesetting, long-term archiving, and journal management. In addition to Swiss francs (CHF), we also accept payment in euros (EUR), US dollars (USD), British pound sterling (GBP), Japanese yen (JPY) or Canadian dollars (CAD).

Invoices are emailed shortly after acceptance to the payment contact provided by the authors. Only official invoices issued by MDPI (@mdpi.com) are valid. We do not authorize any third party to collect the APCs. MDPI is the sole service provider and cannot be held liable for actions by third parties.

Local VAT or Sales Tax will be added if applicable.

For more detailed information on how to pay an invoice, please see our Payment Instructions. Note that many national and private research funding organizations and universities explicitly cover APCs for articles resulting from funded research projects.

Submitted papers should be well-prepared, with good English and clear figures. Authors should resolve issues prior to publication, e.g., in response to reviewer feedback, or risk delays and even rejection. MDPI Author Services offers professional English and Figure Editing.

Discounts are also available for authors from institutes which participate in MDPI's Institutional Open Access Program (IOAP) and members of affiliated societies, on both the APC and additional services including MDPI Author Services.