OpenAlex vs Valyu: A Feature-by-Feature Research Platform Comparison

OpenAlex and Valyu are both research platform solutions designed to address comparable research problems. Valyu specializes in providing a search and DeepResearch API that retrieves full-text evidence, complete with citations, from various academic literature, scientific research, papers, and specialist sources. In contrast, OpenAlex serves as an open scholarly metadata graph containing over 322 million works and is tailored for bibliometric discovery, citation analysis, and structured queries across works, authors, institutions, and topics.

Valyu offers usage-based semantic retrieval of full-text passages and structured citations across academic literature, scientific research, papers, journals, and specialist sources. This means users can obtain detailed, contextually relevant information about the content they are searching for. OpenAlex, on the other hand, delivers an open scholarly graph with structured metadata, including filters, authors, institutions, topics, and citation relationships. This allows for more structured, catalog-like access to scholarly works.

OpenAlex indexes scholarly works as a connected graph, categorizing them into works such as journal articles, conference papers, books, datasets, dissertations, and preprints. These works are split across two corpora: the curated catalogue and a rawer expansion layer. The core catalogue comprises 322,147,582 works, while the expansion layer adds 165,253,218 records, predominantly datasets and single-repository entries, bringing the total to 487,400,800 when both are combined.

The graph links works to authors, sources, institutions, topics, keywords, funders, awards, and publishers. OpenAlex assembles bibliographic coverage from various upstream indexes, including Crossref, PubMed, DataCite, DOAJ, and arXiv. The search parameter for works accommodates title, abstract, and full-text matches and covers the same three fields with its full-text.search filter.

OpenAlex also maintains a content archive of cached full-text PDFs, totaling over 50 million PDFs (equivalent to approximately 250 terabytes) and around 43 million TEI XML files parsed by Grobid.

In contrast, Valyu indexes approximately 40 million academic papers along with web results, financial market data, and various licensed and specialist collections. The academic sources are broken down as follows: PubMed, arXiv, bioRxiv, medRxiv, and chemRxiv update monthly, while Wiley collections cover finance journals and books on a monthly basis, and Health & Life Sciences journals on a quarterly basis.

Valyu also covers clinical trials from ClinicalTrials.gov, USPTO patents, EPO patents, FDA drug labels, and other sources. However, Valyu does not provide full text for every indexed publication; it offers full-text retrieval for open-access content and licensed content with usage restrictions.

The web interfaces of both platforms differ significantly. Valyu's platform provides a search playground that queries across source categories and returns title, URL, content, and structured citations. This interface enables semantic retrieval, which means that an exact-title query matches by meaning rather than string equality, returning the target work along with related materials instead of a single row.

In contrast, OpenAlex presents a search box and filter options. Boolean operators (AND, OR, NOT) must be capitalized, and quotation marks provide phrase matching. Author searches are run through the /authors endpoint, and citation searching is conducted through citation filters.

When comparing features, OpenAlex and Valyu differ in several key aspects. OpenAlex boasts a substantial corpus size of 322 million core works, which expands to 487 million when including the expansion layer. Valyu, however, indexes roughly 40 million academic papers alongside other content types. OpenAPI for OpenAlex is documented and allows for flexible query types, including keyword, Boolean, phrase, proximity, wildcard, and semantic searches.

Valyu, while less explicit about its API documentation, provides semantic full-text retrieval and supports additional source categories such as web search, financial data, and licensed collections.

OpenAlex has a maximum query size of around 4 KB, with filters such as search_type, included_sources, excluded_sources, source_biases, relevance_threshold, start_date, end_date, category, country_code, max_num_results, max_price, pagination options (max 100 per page, with a 10,000-result ceiling and cursor paging beyond this limit), and selectable response fields such as title, URL, content, relevance_score, citations.

Valyu, on the other hand, does not specify a maximum query size, but it supports citation graph features, including cited_by_count, references, related works, DOI, authors, citation count, references, and full-text content for open-access papers plus licensed collections. Valyu also offers web search capabilities, which are not included in OpenAlex.

In terms of full-text content, OpenAlex provides access to 52.4 million works, all of which are open access. These works include access to a cached PDF archive of over 50 million PDFs (approximately 250 terabytes) and around 43 million TEI XML files parsed by Grobid. Valyu, however, delivers full-text content for open-access papers in addition to licensed collections where access is restricted. The platform provides structured JSON for financial data but does not include this feature in its free tier.

OpenALEX offers a free tier with a budget of $1 per day, which includes up to 10,000 API requests. This free tier provides access to metadata for all indexed works and full-text access for open-access papers. Valyu offers a more expensive free tier priced at $10 in credits, with a $20 upgrade option. Both platforms aim to provide up-to-date content, but Valyu’s daily indexing of sources, ranging from daily to quarterly updates, ensures faster access to the latest publications compared to OpenAlex, which updates continuously from its upstream indexes.

However, accessing the latest publications within a week from their publication date may be more reliable with Valyu due to its more frequent update schedules.