2026-07-26 · 6 min read

Junior developers should learn code review before anyone pays them to write code

The numbers on entry-level developer jobs stopped being ambiguous this year. Stanford's AI Index, drawing on ADP payroll data analyzed by Erik Brynjolfsson's team, shows employment for software developers aged 22 to 25 down nearly 20% from the late-2022 peak, while every cohort over 30 held flat or grew. Stack Overflow's look at the same problem adds the pipeline stats: entry-level tech hiring down 25% year over year, tech internship postings down 30% since 2023, and computer science graduates facing 6.1% unemployment, worse than the average across all majors. The ladder didn't get shorter. Its bottom rung got removed.

What exactly disappeared

The entry-level developer job was never really about the output. The boilerplate endpoints, the small bug fixes, the test scaffolding, the glue code: companies paid juniors modestly for that work because doing it is how someone becomes a mid-level engineer. That bargain is what AI broke. The routine tasks went first, exactly as Anthropic's CEO Dario Amodei predicted when he warned AI could eliminate half of entry-level knowledge work. What's left is a circular problem: the tasks that taught fundamentals are automated, so a junior can't get hired without skills they were supposed to acquire on the job that no longer exists.

Read the fine print on the jobs coming back

The loudest counter-signal came from IBM: the company is tripling its entry-level hiring in the US this year. Chief HR officer Nickle LaMoreaux put it provocatively: "And yes, it's for all these jobs that we're being told AI can do." But the interesting part isn't the headcount, it's what IBM did before opening the roles. They rewrote the job descriptions, because the entry-level job of three years ago can now largely be done by AI. The redefined junior developer role centers on AI oversight: working with generated code, judging it, catching what's wrong with it, and knowing when to trust it.

That's worth sitting with. The junior job that's disappearing is "write routine code". The junior job that's being recreated is "supervise the thing that writes routine code". And supervising code you didn't write has a name: code review. The skill that used to mark senior engineers, reading a diff you've never seen and deciding whether it should ship, is quietly becoming the entry requirement.

The catch: nobody teaches it, and now there's no job to learn it on

Review judgment used to be absorbed through years of writing code and watching your own PRs get torn apart. Juniors can't take that path anymore; the years of routine writing are the part that got automated. Meanwhile the interview process is drifting the same direction as the job: more take-homes that hand you an AI-generated codebase and ask what's wrong with it, more review rounds where the question isn't "can you invert a binary tree" but "would you have approved this".

The good news is that review is trainable deliberately, without anyone hiring you first:

• Read code daily, unfamiliar code specifically. Not your own projects. The skill under review is building a mental model of intent from a diff, and it only develops against code you didn't write.
• Use open-source PRs as an answer key. Pick a project you use, read an open PR, write down what you'd flag, then compare against what the maintainer actually said. Free, realistic, slow feedback.
• Practice against planted bugs for fast feedback. The problem with real repos is you never learn what you missed. Training on PRs with known, planted defects closes the loop: every review ends with the full answer.

Proof matters more when the resume is empty

There's a second, colder reason this matters for juniors specifically: with no work history, you have no way to demonstrate judgment. Everyone's resume says "attentive to detail". On DiffDojo the daily challenge and the library are AI-written PRs with planted bugs, and your profile accumulates the measurement: catch rate per bug category, verdict accuracy, false-flag precision, and the blind spots you still have. "I catch 4 of 6 defect classes, and here's the breakdown" is a claim a hiring manager can actually check, which puts it a category above anything else on an entry-level resume. Today's PR is free, no signup.

The rung didn't come back. But the wall it used to lead to now has a different handhold, and unlike the old one, this one can be trained from a laptop before anyone gives you a badge.

Read next: How to practice code review (deliberately)