# Backend Dev > Coding practices for backend development in Atomic CRM. Use when deciding whether backend logic is needed, or when creating/modifying database migrations, views, triggers, RLS policies, edge functions, or custom dataProvider methods that call Supabase APIs. Use when this capability is needed. - Skill: `tomevault-io/backend-dev-2` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/backend-dev-2` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/backend-dev-2/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/backend-dev-2 --- There is no custom backend server. All server-side logic uses Supabase: PostgreSQL (tables, views, triggers, RLS), Auth API, Storage, and Edge Functions. Prefer frontend-only solutions via custom dataProvider methods calling the PostgREST API. When backend logic is needed: - **Aggregation/read optimization**: Create a database view (`CREATE OR REPLACE VIEW` in a new migration). PostgREST exposes views like tables. When underlying table columns change, update the `contacts_summary` and `companies_summary` views too. - **Complex mutations** (multi-table writes): Create a Supabase edge function in Deno. Stored procedures via RPC are less preferred (code lives in migrations, harder to maintain). On the frontend, expose the edge function as a custom dataProvider method (using `httpClient(`${supabaseUrl}/functions/v1/`)`) and call it via react-query. (e.g. `salesCreate()` → `/functions/v1/users`, `mergeContacts()` → `/functions/v1/merge_contacts`) Edge function conventions: - Shared utils in `supabase/functions/_shared/` — reuse `authentication.ts`, `supabaseAdmin.ts`, `cors.ts`, `utils.ts` - Follow the middleware chain pattern: CORS preflight → `authenticate()` → handler - `verify_jwt = false` in config.toml, so JWT validation is manual via `authenticate()` Other conventions: - New tables need RLS policies and the auto-set `sales_id` trigger (see migration `20260108160722`) --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/marmelab) — claim your Tome and manage your conversions.