The #1 risk on OWASP's API Security Top 10 (2023 edition) is broken object level authorization (OWASP). In plain terms: user A changes an ID in a URL and sees user B's invoice. Nothing crashes, and no test turns red. It's a backend bug, and it's the kind of mistake that separates a backend developer you can trust with customer data from one you can't. Language choice matters less than you think. Judgment about data, failure, and access matters more.
Key Takeaways
- Hire backend developers for data modeling, failure handling, and authorization. Pick the language second.
- Access control failures top both the OWASP Top 10 and the OWASP API Security Top 10. Test for them directly.
- Ask about incidents they've owned. Production scars are the best signal of seniority.
- The BLS puts the US median software developer wage at $135,980, and senior backend engineers sit above it.
What "Backend" Actually Covers
A backend developer owns the parts of your product users never see: the API, the database, background jobs, integrations with payment providers and email services, and the monitoring that tells you when any of it breaks. In a startup, that often includes deployment too.
The skills that matter across every stack:
Data modeling. Picking tables, keys, and constraints that still make sense after two years of product changes. A bad schema is expensive to undo. Our Postgres vs MongoDB guide covers one of the first choices they'll face.
Failure handling. Networks fail, third-party APIs time out, and webhooks arrive twice. Senior backend engineers design for all of it with retries, timeouts, and idempotent operations.
Access control. Broken access control is also #1 on the general OWASP Top 10, 2025 edition (OWASP). Every endpoint needs to check that this user may touch this record.
Operating the service. Google's SRE book defines an SLO as "a target value or range of values for a service level that is measured by an SLI," and adds that insisting on 100% is "both unrealistic and undesirable" (Google SRE). A backend hire should know what their service's targets are and how they'd measure them. See error budgets and SLOs.
How to Screen
| Area | Question | Strong answer |
|---|---|---|
| Authorization | "Here's an endpoint: `GET /invoices/:id`. What's wrong?" | Spots the missing ownership check, fixes it at the query level, adds a test |
| Failure | "The payment provider times out. What happens?" | Timeouts, retries with backoff, idempotency key, reconciliation job |
| Data | "Model subscriptions with plan changes mid-cycle." | Thinks about history, proration, and constraints before writing code |
| Incidents | "Tell me about an outage you caused." | Specific story, what they changed afterward, no blame-shifting |
| Scale | "This query got slow. What now?" | Reads the query plan, checks indexes, measures before and after |
The incident question matters most. Candidates who have never broken production have usually never owned it.
Which Language?
Pick the language your codebase already uses, then hire a strong backend engineer in it. If you're starting fresh, the choice between Node, Python, Go, Java, and others is covered in Django vs Rails vs Node and Node.js vs Python. Our language-specific guides go deeper: Node.js, Java, Python, and Go.
A Concrete Version
A seed-stage B2B SaaS company has 30 paying customers and a backend written by a freelancer who has moved on. The founder wants to hire a backend developer and budgets using the BLS median wage of $135,980 (BLS).
That budget is off in two ways. First, wages are only about 70% of what private employers spend on compensation, with benefits making up the other 30% (BLS), so even the median salary implies roughly $194,000 a year in total cost. Second, the median covers every level of experience. A senior engineer who can own a production backend alone costs more.
The founder has three options: pay the US senior premium, hire a mid-level US developer and accept more risk, or hire a senior nearshore engineer at a cost typically 40 to 60% below the fully loaded US figure, working the same hours. Whichever they choose, the first-month task list is the same: audit every endpoint for ownership checks, add monitoring and alerting, and write tests around billing. Do the ownership audit first. An inherited codebase with no tests is exactly where a missing check hides.
The Honest Counterpoint
The most common hiring mistake here is trusting the title. "Backend developer" covers a wide range. A developer who has spent five years inside a large company's internal platform may be excellent and still struggle when they have to own everything, including deployment, alone. Ask how much of the stack they personally owned.
You may also not need this hire yet. If your product is mostly a frontend on top of a managed backend (Supabase, Firebase, or a no-code tool), a strong full-stack developer may be the better first hire. See how to hire a full-stack developer.
Frequently Asked Questions
What's the difference between a backend developer and a full-stack developer?
A backend developer goes deeper on APIs, data, and infrastructure. A full-stack developer covers both sides, usually with less depth on each. Early teams often start full-stack and add backend depth as data and scale grow.
How do I test a backend developer if I'm not technical?
Use a paid take-home with a real bug in it, and have a trusted engineer review the result. Our guide on interviewing developers when you're not technical has a step-by-step process.
Which backend language is easiest to hire for?
By raw numbers, JavaScript and Node.js have the largest pools. But the best language is the one your codebase already uses.
The Bottom Line
Hire backend developers for authorization discipline, failure handling, and data judgment, and test each one with a concrete scenario. The language is the easy part. If you want senior backend engineers who have passed that kind of screen, see senior backend developers in LATAM, see available engineers, or get a quote for your role.
Roberto Espinoza is CEO of Ruzora, which helps US startups hire pre-vetted senior LATAM engineers, with a vetted shortlist in 72 hours. See available engineers.
