What it is
STANAG 4093 is a NATO Standardization Agreement, currently Edition 5, dated 12 March 2018. It is not a technical specification. It is the agreement by which NATO nations commit to ratify and implement APP-30, Edition A, the Allied Publication that sets out mutual acceptance of qualification for electronic and electrical components used in military equipment. The qualification process and technical criteria that a reader usually wants live inside APP-30 itself, not inside this six-page cover. Read on its own, STANAG 4093 requires almost nothing of a supplier directly. Its obligations run to nations, and it reaches a contractor only indirectly, once a nation has implemented it and a contract or tender names APP-30.
Who it binds, and how
STANAG 4093 is explicit that it binds nations rather than organisations. Its letter of promulgation describes the enclosed agreement as one "which has been ratified by member nations, as reflected in the NATO Standardization Document Database (NSDD), is promulgated herewith." Ratification and implementation are separate steps, and the document invites nations that have not yet reported their position to "advise the NSO of their intention regarding its implementation." So "is STANAG 4093 mandatory" has no single answer: it depends on whether a given nation has ratified and implemented it, and, for a supplier, on whether a specific contract invokes APP-30 as a result.
What the agreement actually commits nations to
The stated aim is to respond to two interoperability requirements: to "enable multinational cooperation within the field of procurement of electronic and electrical components," and to "define multinationally-agreed processes and procedures for the mutual acceptance of qualification of electronic and electrical components." Under "Agreement," participating nations agree to implement APP-30, Edition A. None of this is written as a duty on a supplier; it is a duty on the nation, and on whichever national body runs component qualification.
A cover agreement, not the qualification process
A reader who only has STANAG 4093 in hand does not yet have anything to qualify a component against. The actual qualification process and acceptance criteria are in APP-30. This document's own "Other related documents" field reads simply "None," which is a useful marker of how narrow its own scope is: it covers one publication and nothing beside it.
Reporting and review
Nations are invited to report their effective implementation of the STANAG using the form at Annex H to AAP-03(J); partner nations report their adoption using the form at Annex G to AAP-03(J). The STANAG itself "is to be reviewed at least once every three years," with the result recorded in the NSDD - a check on whether the agreement is still current, not an audit of any organisation. The agreement is supervised by the CNAD Life Cycle Management Group (AC/327 LCMG), with Germany's defence procurement office (BAAINBw) named as custodian.
What it does not cover
STANAG 4093 names no qualification test, no acceptance criterion and no product beyond "electronic and electrical components for military use" - the detail that a component engineer actually needs sits entirely in APP-30. It also names no assessment or certification scheme of its own: the only stated check is that the STANAG itself is reviewed periodically, not that an organisation or a component is certified.