Attorney Alexander Kashumov practices in the field of administrative, civil and criminal law. Represents cases before national and international courts, as well as administrative bodies and jurisdictions. He made statements before the Constitutional Court. He represents administrative, civil and criminal cases in partnership with his colleagues Daniela Mihaylova, Stoyan and Andrey Terziiski, and Teodor Borodjiev. The law office has good cooperation with America for Bulgaria Foundation, Trust for Social Achievement and  Open Society Institute in Sofia.

Administrative law: He succeeded to achieve positive changes in court practice in cases relating to access to public information, personal data protection, freedom of expression, protection from discrimination,  environmental protection, nuclear energy cases, dismissal of civil servants, conflict of interest, spatial planning, expropriation of property, protection against illegal decisions and actions, malpractice and wrongdoings of state and municipal authorities and compensation in such cases. He represented also lawsuits against the legality of normative acts affecting human rights. In 2008 he won the landmark case of AIP for declaring null and void the provisions of a regulation providing direct access of the police and secret services to e-communication data (data retention), and in 2009 successfully represented the Supreme Bar Council in an interpretative case before the SAC where the Plenary of the count found the associations have legal standing to challenge the lawfulness of general administrative decisions that affect the rights of their members and other target groups.

Civil law: Attorney Kashumov deals with cases in the field of contracts, tort, property law, labor law, etc..

Criminal law: Lawyer Kashumov has contributed to the development of court practice relating to criminal (and civil) defamation, protecting journalists and the media in dozens of lawsuits for libel and defamation. He also works on high profile criminal cases of public interest.

Supreme courts: Between 2000 and 2020, Kashumov appealed before the Supreme Administrative Court (SAC) and the Supreme Court of Cassation (SCC) in hundreds of cases, including in plenary sessions of the Supreme Administrative Court and the Criminal Division of the Supreme Court of Cassation.

International courts: Lawyer Kashumov represents applications and prepares briefs before the European Court of Human Rights (ECtHR) in Strasbourg on various cases related to the protection of human rights. He has won the cases: Sasov and Others, Kasabova, Idakiev, Hadzhiev (together with Mihail Ekimdzhiev), Boykanov, Aneva and Others, Yonchev, Kostov and Others, National movement "Ekoglasnost", Ekimdzhiev and Others (together with Mihail Ekimdzhiev). On behalf of AIP he contributed to joint amicus curiae briefs in the ECtHR cases: Mosley v. United Kingdom, the landmark Grand Chamber case Magyar Helsinki Bizottság v. Hungary, the case Satakunnan Markkinapörssi Oy and Satamedia Oy v. Finland etc.

Constitutional court: Attorney Kashumov has prepared statements of AIP before the Constitutional Court. Many of the arguments put forward in the briefs on constitutional cases no 14/2011, no 13/2017, no 12, 13 and 14/2018 and 4/2019 were considered and accepted in Decisions no 4 of 26 March 2012, Decision No 8 of 23 April 2018, Decision no 5 of 19 April 2019 and Decision no 8 of 15 November 2019 of the Constitutional Court in these cases.

President: Attorney Kashumov formulated the request of AIP and 26 other non-governmental organizations to the President to veto the amendments to the Environmental Protection Act of July 2017. On August 8, the head of state vetoed the law and turned it back to parliament. In July 2018 Kashumov formulated another request of AIP to the Preident, supported by 50 non-governmental organizations, which resulted in vetoing the amendments to the Administrative Procedure Act introducing high court fees and restricting access to courts. On July 31, the President returned the law to parliament for a new consideration. In February 2019 the President vetoed a provision of the amendments to the Personal Data Protection Act (PDPA) which was criticized by AIP. The veto was overcome by the Parliament but the Constitutional court declared the disputed Art. 25з of the PDPA unconstitutional with its Decision no 8 of 15 November 2019.

Other: Provides consultations on these matters and represents individuals and legal entities before administrative bodies, notaries, bailiffs, committees, etc.