https://laurentiu-niculescu.co.uk Software engineer in London. Windows security tooling in Python, a multi-tenant client platform in TypeScript, and two live web apps on Linux servers I provision and harden myself. en-gb https://laurentiu-niculescu.co.uk/writing/permission-check-two-jobs https://laurentiu-niculescu.co.uk/writing/permission-check-two-jobs One flag guarded both "can see every client" and "can create logins". Splitting it into two questions took an afternoon. Noticing it took a year. Sun, 16 Aug 2026 00:00:00 GMT https://laurentiu-niculescu.co.uk/writing/dmarc-check-that-passed-everything https://laurentiu-niculescu.co.uk/writing/dmarc-check-that-passed-everything Looking for the record is not the same as reading it. A substring match gave a green tick to `+all` and to `p=none`, which are the two ways of having the record and none of the benefit. Wed, 05 Aug 2026 00:00:00 GMT https://laurentiu-niculescu.co.uk/writing/258mb-of-json https://laurentiu-niculescu.co.uk/writing/258mb-of-json An endpoint that worked fine in testing started returning 502s in production. The response was a quarter of a gigabyte, and most of it was photographs. Thu, 09 Jul 2026 00:00:00 GMT https://laurentiu-niculescu.co.uk/writing/every-script-backs-up-what-it-touches https://laurentiu-niculescu.co.uk/writing/every-script-backs-up-what-it-touches The rule came from breaking a working config with no way back. It costs three lines and it has saved me more times than I would like to admit in public. Sun, 14 Jun 2026 00:00:00 GMT