Here are Perth-based companies that provide custom software development (web, mobile, databases, APIs, SaaS and enterprise systems). I’ve listed a short note and linked a source for each so you can check portfolios, services and contact details.

• Lateral — long‑standing Perth custom/enterprise software developer (bespoke web & database systems). (lateral.com.au, goodfirms.co)
• Hatchet — Perth digital agency that builds custom web apps, databases, integrations and cloud solutions. (hatchet.com.au)
• OneIT — Perth firm focused on bespoke business systems, databases, CRM/roster and reporting solutions. (oneit.com.au)
• Redi Software (Redi Apps) — Perth (Joondalup) custom software and SaaS development, full life‑cycle delivery and support. (redisoftware.com.au)
• Dapper Apps — Perth mobile & web app agency (native/hybrid apps and backend platforms). (dapperapps.com.au)
• Itomic — digital/innovation agency with a Perth office; builds bespoke web and app solutions for enterprise and government clients. (innovination.com)
• Limitless Devs — Perth small agency specialising in custom apps, websites and software for SMEs (local WA presence). (goodfirms.co, web.org.au)
• AB Web Developers — Perth web & web‑software specialist (est. 1998) offering custom web systems and portals. (abweb.com.au)
• QL Tech — Perth‑based office offering agile/custom web & mobile development (also has offshore delivery capability). (qltech.com.au)

Notes and next steps (quick guidance)

• How to pick: review each company’s case studies/portfolio, check tech stack fit (e.g., Node/React, .NET, PHP/Laravel, mobile native vs cross‑platform), confirm IP & source‑code ownership, ask about ongoing support/SLAs, and get 2–3 quotes with timelines.
• Budget/scale: some above are small boutique teams (better for lean MVPs/SMEs) and some have larger enterprise capability — mention your expected budget and scale when you contact them to get accurate proposals.
• If you want, I can: (a) shortlist 3 vendors from this list matched to your project type/stack/estimate, or (b) draft an RFP/email template you can send to these firms. Which would you prefer?