Clarivate Analytics' Web of Science is an online subscription-based citation indexing service which gives access to multiple databases that reference cross-disciplinary research and which allows for comprehensive citation search and in-depth exploration of specialized sub-fields within a scientific discipline. It consists of 6 core databases, a number of specialist collections, as well as regional databases and currently contains more than 160 million records and over 1.7 billion cited references. A select number of Atlantis Press journals and proceedings is indexed in Web of Science databases such as the Science Citation Index Expanded (SCIE), the Emerging Sources Citation Index (ESCI) and the Conference Proceedings Citation Index (CPCI).

Elsevier's Scopus is the world's largest abstract and citation database of peer-reviewed scientific journals, books and conference proceedings which covers research topics across all scientific, technical and medical disciplines. The database currently contains more than 75 million records and over 1.4 billion cited references, while it also offers various smart tools and metrics to track, analyze and visualize research. At present a select number of Atlantis Press journals and proceedings is indexed in Scopus and a number of applications are in progress.

MEDLINE is the U.S. National Library of Medicine premier bibliographic database that contains more than 25 million references to journal articles in life sciences with a concentration on biomedicine. The subject scope of MEDLINE is biomedicine and health, broadly defined to encompass those areas of the life sciences, behavioral sciences, chemical sciences and bioengineering needed by health professionals and others engaged in basic research and clinical care, public health, health policy development or related educational activities. MEDLINE also covers life sciences vital to biomedical practitioners, researchers and educators, including aspects of biology, environmental science, marine biology, plant and animal science as well as biophysics and chemistry. A select number of Atlantis Press journals in health and medical sciences is indexed in MEDLINE.

PubMed Central (PMC) is a free full-text digital archive of biomedical and life sciences journal literature which has been developed and operated by the National Center for Biotechnology Information (NCBI), a division of the U.S. National Library of Medicine (NLM) at the U.S. National Institutes of Health (NIH). As of today, PMC contains more than 5.9 million full-text articles spanning several centuries of biomedical and life science research (late 1700s to present). Participation by publishers in PMC is voluntary, although participating journals must meet certain scientific and technical standards and content must be deposited as per the NIH Public Access Policy. A select number of Atlantis Press journals in health and medical sciences is indexed in PMC.

The Directory of Open Access Journals (DOAJ) is a community-curated online directory of open access journals which aims to be the starting point of all information searches for quality, peer-reviewed, open access material. DOAJ's mission is to increase the visibility, accessibility, reputation, usage and impact of quality, peer-reviewed, open access scholarly research journals globally, regardless of discipline, geography or language. At present, the directory contains more than 14,000 open access journals from 133 countries and more than 4.6 million open access articles covering all areas of science, technology, medicine, social science and humanities. All Atlantis Press journals are indexed in DOAJ.

Elsevier's Ei Compendex (Engineering Index - COMPuterized ENgineering inDEX) on Engineering Village is the broadest and most complete engineering literature database in the world. It provides a holistic and global view of peer-reviewed and indexed publications with over 20 million records from 77 countries across 190 engineering disciplines. A select number of Atlantis Press journals (i.e. within relevant subject areas) is indexed in Ei Compendex.

PubMed is a free search engine which provides access to references and abstracts from biomedical and life sciences literature and which has been developed and maintained by the National Center for Biotechnology Information (NCBI), a division of the U.S. National Library of Medicine (NLM) at the U.S. National Institutes of Health (NIH). PubMed comprises more than 30 million citations and abstracts, primarily from MEDLINE but also from PubMed Central (PMC) and other life science journals and books, covering the fields of biomedicine and health and portions of the life sciences, behavioral sciences, chemical sciences and bioengineering. Many PubMed records also contain links to full-text articles, some of which are freely available (often in PMC). A select number of Atlantis Press journals in health and medical sciences is indexed in PubMed.

Portico is a community-supported digital preservation archive that safeguards permanent access to e-journals, e-books and digital collections for researchers, scholars and students. The Portico digital preservation service is part of ITHAKA, a not-for-profit organization which aims to "help the academic community use digital technologies to preserve the scholarly record and to advance research and teaching in sustainable ways". The Portico archive currently contains more than 88 million journal articles, more than 1 million books and more than 4 million other digital collection items from a total number of 663 participating publishers. To comply with NLM requirements (for indexation in MEDLINE and PMC) a select number of Atlantis Press journals is preserved in the Portico archive.

The China National Knowledge Infrastructure (CNKI) is a key national information construction project launched by Tsinghua University and supported by the PRC Ministry of Education, PRC Ministry of Science and Technology, PRC Ministry of Propaganda and the PRC General Administration of Press and Publication. It is dedicated to the mass digitization of China knowledge resources as well as creating the platform for global dissemination and value-added services (CNKI was designated as the second agent of DOIs in mainland China by the International DOI Foundation in 2013). It comprises the China Integrated Knowledge Resources Database which contains over 90% of China knowledge resources. Most of the Atlantis Press proceedings and journals content is indexed in CNKI.

Wanfang Data is an affiliate of the Chinese Ministry of Science & Technology which provides access to a wide range of database resources serving as a gateway to Chinese culture, medicine, business, science, engineering, etc. The Wanfang Data electronic resources comprise more than 43 million journal articles, close to 5 million dissertations and theses, more than 4 million conference papers and a broad collection of Chinese statistical data, patents, etc. Most of the Atlantis Press proceedings and journals content is indexed in Wanfang.

The dblp computer science bibliography is an online reference for biblio-graphic information on major computer science publications. Starting at the University of Trier in 1993 and owned by the Leibniz-Zentrum für Informatik since 2018, it evolved from a small experimental web server into a popular open-data service for the computer science community. The dblp mission is to support computer science researchers by providing free access to high-quality bibliographic metadata and links to electronic editions of publications. The dblp currently indexes more than 5.1 million publications, published by over 2.5 million authors. All Atlantis Press journals in fields related to computer science are indexed in the dblp.

ProQuest's Ulrichsweb is the standard online library directory and database for journals, magazines, newspapers and other periodicals. As such, it is regarded as the global authority for serials knowledge and analysis which comprises more than 383,000 serials from over 90,000 publishers covering 977 subject areas and 200 different languages. Records include searchable TOCs, ISSN, title, publisher, online availability, subject area, language, list prices and more. All Atlantis Press serial publications are indexed in Ulrichsweb.

Google Scholar is a freely accessible web search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines. The Google Scholar index includes most peer-reviewed online academic journals and books, conference papers, theses and dissertations, preprints, abstracts, technical reports, and other scholarly literature, including court opinions and patents. It is estimated to contain more than 160 million documents and continues to cover approximately 90% of all articles published in English. All content published on the Atlantis Press platform is indexed in Google Scholar.