Spreadsheets and low-code covers the tools most engineers underrate: Excel, Google Sheets, Notion databases, Airtable, plus the no-code automation platforms (Zapier, n8n, Make) that connect them. Used well, this stack handles 80% of the internal-tools work that would otherwise require a custom application — at zero engineering cost and with minimal maintenance.
The skills that compound: writing complex array formulas in Excel / Sheets (LAMBDA, LET, dynamic arrays), modeling relational data in Airtable without abusing a spreadsheet, and designing automation workflows that don't fall over the moment the source schema changes. Most engineers who learn these tools well end up replacing custom-built CRUD apps with spreadsheet-based equivalents.