Salesforce Platform Developer I — Skills Reference

Salesforce Platform Developer I — Skills Reference

Overview

The Salesforce Certified Platform Developer I (PD1) credential validates that a developer understands how to build, deploy, and maintain custom business logic and user interfaces on the Lightning Platform using programmatic tools. It covers the full Apex development lifecycle — data modeling, SOQL/SOSL queries, trigger design, asynchronous processing, Lightning Web Components, Visualforce, unit testing, and deployment tooling — alongside an understanding of when declarative tools (Flow, validation rules, formula fields) are preferable to code.

This file is an operational playbook, not an exam outline. Each section states the rule as an actionable instruction with concrete limits, decision criteria, anti-patterns to catch in review, and live-org verification steps. Always verify structural assumptions against the live org — SFDX metadata can lag, and FLS/picklist state is not captured in XML.

Load this skill when… writing or reviewing Apex triggers, SOQL/SOSL queries, or LWC components; debugging governor-limit errors or FLS/sharing issues in code; designing trigger handlers or async Apex patterns; deploying SFDX metadata and hitting field-permission or deployment errors. Not this skill: declarative-only config (profiles, flows, sharing rules) → see salesforce-administrator; advanced async/integration/LDV patterns or design patterns → see salesforce-platform-developer-2; LWC front-end JavaScript deep dives → see salesforce-javascript-developer-1.

Verify steps assume nothing about your tooling — use your project's Salesforce MCP connection, the Salesforce CLI (sf), or the Salesforce setup UI, in that order of preference.

Credential logistics and study path: see references/study-resources.md.

Uncertainty & Escalation

• Always re-verify live: governor limit numbers (SOQL/DML/CPU/heap) [volatile — verify live]; sandbox storage sizes [volatile — verify live]; LWC lifecycle API changes and decorator behavior across API versions [volatile — verify live]; any coverage threshold or deployment requirement.
• Live wins: if this skill's numbers or rules conflict with what the Apex runtime, deploy output, or official Salesforce docs show, treat the live system as authoritative. Log the discrepancy immediately using the Feedback protocol below.
• Escalate to a human before proceeding: production deployments touching managed-package Apex or triggers without sandbox validation; any code path that hard-deletes or mass-updates production records; adding without sharing to a class that processes PII or financial data (v67+ note: without sharing is now an explicit opt-in, not the default); disabling or bypassing a package trigger framework in production.
• Confidence taxonomy: facts in this skill are stable unless tagged [volatile — verify live] or [opinion — house style]. When in doubt, describe the object or run a SOQL query rather than trusting repo XML.

Governor Limits — Know These Cold

These are the hard ceilings the runtime enforces per transaction. Internalize the numbers; most "this will fail in bulk" decisions reduce to one of these.