Estimators, planners, and site teams work from one project record in OpenConstructionERP, a self-hosted construction workspace that carries a job from priced bill of quantities through tender, schedule, and site diary. The BOQ editor organizes sections, positions, and reusable assemblies with overhead, profit, VAT, and contingency markups, validates against DIN 276, NRM, and MasterFormat, and exports to PDF, Excel, CSV, or GAEB XML. Pricing draws on 120,000+ cost items across nine cost bases and a 7,000+ resource catalog, with regional price adjustment and semantic search. Quantities come from PDF plans measured on screen or from RVT, IFC, DWG, and DGN models; a 3D viewer filters elements and links them to BOQ positions, clash detection checks federated models, and an AI estimator drafts positions from text, photos, or drawings via the LLM you connect. Gantt schedules show dependencies and critical path, while earned value and S-curves track budget against actual. Tender comparison lines up subcontractor bids, and contracts, variations, and interim payment claims stay tied to the contract sum. On site, daily diaries with health and safety tracking, punch lists, and a carbon module totaling embodied emissions from the BOQ keep field work in the same system. The interface speaks 44 languages with right-to-left support, 293 guided cases teach real workflows on a demo project, and a REST API, webhooks, and module builder extend it. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. AGPL-3.0 licensed.