The texts are provided with word-by-word morphological annotation with homonymy resolved. The annotation was done manually using the Morphy workspace (developed by Timofey Arkhangelsky) and is based on an automatically updated dictionary. Lemmas are given in Old East Slavic form, reflecting the state before the loss of yers (e.g., сълати, дьнь).

The word-by-word annotation also includes the location of each word form in a specific manuscript (page/column and line). For texts translated from Greek, the corresponding Greek lemmas and word forms (or their combinations) are provided alongside the Slavic forms. Greek correspondences are available for a total of 237,000 Slavic word usages.

Search is available by lemma, word form, grammatical features, and also by Greek lemmas and word forms. To facilitate searches, a drop-down list of Slavic and Greek lemmas is available, along with virtual Slavic and Greek polytonic keyboards.

For distinguishing homonyms, it is recommended to specify the part of speech when searching for a specific lemma and to indicate gender for nouns. If homonyms have identical grammatical features (e.g., лукъ ‘weapon,’ лукъ ‘saddle bow,’ and лукъ ‘plant’), the drop-down dictionary that appears during lemma entry will include three separate lemmas for лукъ, each with its meaning indicated. Thus, it is possible to search for each homonym separately. There is also an option to search using the undifferentiated lemma. In this case, the user must carefully review all the retrieved contexts to differentiate the homonyms manually. Assistance is provided by the drop-down dictionary: for texts where at least two homonyms with identical grammatical features are used, the meaning of each word form is indicated. If only one homonym appears in the text—usually the most common one—its meaning may not be displayed.

The texts are supplemented with metadata that specify the genre, whether the text is a translation or original, the creation date of the original and its copies, a brief annotation of the text, and the source from which the text is included in the corpus. Users can also select specific texts or groups of texts. Charters are grouped by origin, and these groups can be selected with a single click.

In the Old East Slavic corpus, many works are represented in multiple versions, such as The Tale of Bygone Years in the Laurentian and Hypatian Chronicles, different copies of the Smolensk-Riga Treaty of 1229, and The Life of Theodosius as part of both the Uspensky Collection and the Kiev-Pechersk Patericon. Although all versions of a text are important for the study of linguistic history and corpus searches due to their textual, orthographic, and linguistic differences, including multiple versions of the same work can significantly skew statistical results, especially in smaller corpora.

The parameter "Each text in one version" allows for a selection that excludes multiple versions of the same work. The choice of the "main" version is somewhat arbitrary (e.g., the Hypatian version was chosen for The Tale of Bygone Years, while a later version from the Patericon was selected for The Life of Theodosius). It should also be noted that Old East Slavic texts created at different times often contain significant textual overlaps and borrowings, such as between The Tale of Bygone Years and The Tale of Boris and Gleb, The Tale of Igor's Campaign and The Zadonschina, colophons by different scribes or the treaties of Novgorod with various princes. Such cases are treated as separate texts.

The Old East Slavic corpus includes the "Word at a glance" feature, which displays automatically calculated similar words with similar contexts (for content words), as well as paradigms of encountered noun word forms in various morphological variants and orthographies.