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Hiring PostgreSQL Developers: The Complete Guide

Market Snapshot
Senior Salary (US)
$150k – $200k
Hiring Difficulty Hard
Easy Hard
Avg. Time to Hire 4-6 weeks

SQL Developer

Definition

A SQL Developer is a technical professional who designs, builds, and maintains software systems using programming languages and development frameworks. This specialized role requires deep technical expertise, continuous learning, and collaboration with cross-functional teams to deliver high-quality software products that meet business needs.

SQL Developer is a fundamental concept in tech recruiting and talent acquisition. In the context of hiring developers and technical professionals, sql developer plays a crucial role in connecting organizations with the right talent. Whether you're a recruiter, hiring manager, or candidate, understanding sql developer helps navigate the complex landscape of modern tech hiring. This concept is particularly important for developer-focused recruiting where technical expertise and cultural fit must be carefully balanced.

What PostgreSQL Developers Actually Do

"PostgreSQL Developer" can mean different things depending on your needs:

Application Developers with PostgreSQL Skills

Most common need. These developers:

  • Write efficient queries integrated with application code
  • Design schemas for new features
  • Understand indexes enough to avoid obvious performance problems
  • Use ORMs (Prisma, SQLAlchemy, ActiveRecord) effectively

Every backend developer should have this level of PostgreSQL knowledge.

Database Engineers / DBAs

Specialized role focusing on:

  • Query optimization and performance tuning
  • Schema design for complex domains
  • Replication, high availability, disaster recovery
  • Capacity planning and scaling strategies
  • Security, backup, and compliance

Needed when your database is a critical bottleneck or you handle sensitive data.

Data Engineers with PostgreSQL

Focus on data pipelines:

  • ETL processes moving data in/out of PostgreSQL
  • Analytical queries and reporting
  • Integration with data warehouses
  • Large-scale data migrations

Skill Levels: What to Test For

Level 1: Basic SQL (Every Backend Dev)

  • Write SELECT, INSERT, UPDATE, DELETE
  • Basic JOINs and aggregations
  • Understand primary keys and foreign keys
  • Use an ORM correctly

Red flag: Can't write a JOIN without Stack Overflow

Level 2: Competent PostgreSQL User

  • Knows when to add indexes (and when not to)
  • Understands query plans (can read EXPLAIN output)
  • Handles transactions and concurrency
  • Writes migrations that don't break production

This is the minimum for backend developers at your company.

Level 3: PostgreSQL Expert

  • Optimizes slow queries systematically
  • Designs schemas for complex business domains
  • Understands PostgreSQL internals (MVCC, vacuum, WAL)
  • Handles replication, partitioning, and high availability

This is DBA/Database Engineer territory.


Common Use Cases and What to Look For

Transactional Applications (OLTP)

E-commerce, SaaS, banking:

  • Priority skills: Transaction handling, index optimization, connection pooling
  • Interview signal: "How do you handle a slow query in production?"
  • Red flag: Doesn't know what an index scan vs seq scan means

Analytical/Reporting (OLAP-lite)

Dashboards, business intelligence:

  • Priority skills: Complex aggregations, window functions, materialized views
  • Interview signal: "How would you optimize a report that scans 100M rows?"
  • Red flag: Only knows basic GROUP BY

JSON/Document Hybrid

Flexible schemas with relational benefits:

  • Priority skills: JSONB queries and indexing, when to use JSON vs tables
  • Interview signal: "When would you use JSONB vs a normalized schema?"
  • Red flag: Treats PostgreSQL like MongoDB (stores everything as JSON)

Geospatial (PostGIS)

Location-based applications:

  • Priority skills: PostGIS functions, spatial indexing
  • Interview signal: "How would you find all points within 10km?"
  • Red flag: Never heard of PostGIS

Common Hiring Mistakes

1. Testing Basic SQL Only

Fizz-buzz level SQL (SELECT * FROM users WHERE active = true) doesn't differentiate candidates. Test query optimization, schema design decisions, and handling edge cases.

2. Ignoring Production Experience

Theoretical knowledge differs from battle scars. Ask about production incidents: "Tell me about a database problem you debugged" reveals real experience better than trivia questions.

3. Conflating PostgreSQL with Generic SQL

PostgreSQL has specific features (JSONB, CTEs, window functions, specific indexing) that differ from MySQL or SQL Server. If you need PostgreSQL expertise, test for PostgreSQL.

4. Hiring a DBA When You Need a Backend Dev

If queries are slow because application developers write N+1 queries, hiring a DBA won't fix that. Understand where your problem actually is.


Interview Approach

For Application Developers

Focus on practical scenarios:

  • "Here's a slow page. Walk me through debugging it."
  • "Design a schema for [your domain problem]."
  • "This query is slow. How would you investigate?"

For Database Engineers/DBAs

Focus on operational knowledge:

  • "Walk me through your backup and recovery strategy."
  • "How do you handle a table that's grown to 1TB?"
  • "Explain PostgreSQL's MVCC and its implications."

Recruiter's Cheat Sheet

Questions That Reveal Skill Level

Question Junior Answer Senior Answer
"A query is slow. What do you do?" "Add an index" "Run EXPLAIN ANALYZE, check the plan, identify if it's index, I/O, or lock-related"
"When shouldn't you add an index?" "I always add indexes for speed" "Write-heavy columns, low-cardinality columns, when table is small"
"What's database normalization?" "Making tables smaller" Explains trade-offs between normalization and denormalization for specific use cases

Resume Green Flags

  • Specific performance improvements ("Reduced query time from 30s to 200ms")
  • Production scale experience ("Managed 500GB PostgreSQL cluster")
  • Mentions specific PostgreSQL features (JSONB, PostGIS, partitioning)
  • Migration experience (version upgrades, schema changes)

Resume Red Flags

  • Only lists SQL without database-specific experience
  • No mention of indexes or performance
  • "Expert in databases" but only tutorial projects

Frequently Asked Questions

Frequently Asked Questions

Depends on your scale. Under 100GB and limited complexity: backend developers with solid PostgreSQL skills suffice. Over 500GB, complex replication, or strict compliance requirements: consider a dedicated DBA. Many companies hire backend devs first and add DBAs when database work exceeds 50% of someone's time.

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