PG&E · Software Engineer
Updated · 2026-10-02

PG&E Software Engineer
Interview Guide

THE 60-SECOND BRIEF

A Software Engineer at PG&E (Pacific Gas and Electric) plays a critical role in maintaining and modernizing the energy infrastructure that powers millions of homes and businesses across California. Unlike typical Silicon Valley tech companies, software engineering here sits at the crucial intersection of information technology (IT) and operational technology (OT). Your work directly impacts grid reliability, wildfire mitigation, asset management, and customer-facing utility applications. Engineers in this role build, deploy, and maintain systems that handle massive scale and require near-zero downtime. You might find yourself working on geographic information systems (GIS), grid control platforms, supervisory control and data acquisition (SCADA) integrations, or enterprise-scale deployment scripts.

This guide is scoped to a Software Engineer candidate at PG&E.

PG&E candidates report 2 rounds over 2-4 weeks. The stages below are what candidates describe, not a published process.

Behavioral Interviewing (STAR Method)Safety Practices / Safety EmphasisPower Systems Engineering

24 min read

Browse Software Engineer questions

See the practice prompts

20Practice promptsAcross five skill areas

A Software Engineer at PG&E (Pacific Gas and Electric) plays a critical role in maintaining and modernizing the energy infrastructure that powers millions of homes and businesses across California. Unlike typical Silicon Valley tech companies, software engineering here sits at the crucial intersection of information technology (IT) and operational technology (OT). Your work directly impacts grid reliability, wildfire mitigation, asset management, and customer-facing utility applications. Engineers in this role build, deploy, and maintain systems that handle massive scale and require near-zero downtime. You might find yourself working on geographic information systems (GIS), grid control platforms, supervisory control and data acquisition (SCADA) integrations, or enterprise-scale deployment scripts. The software you write and support ensures that field engineers, grid operators, and millions of customers have access to real-time, safety-critical data. Joining PG&E as a Software Engineer means taking on a high-stakes responsibility where software bugs can have real-world physical consequences. This makes the development culture highly structured, with a deep emphasis on safety, compliance, and methodical risk management. It is an exceptionally rewarding career path for engineers who want to see their code drive tangible, essential physical infrastructure.

01

Pre-employment Tests

reported

Candidates must pass the Physical Test Battery or a specialized Technical Test before proceeding.

What to demonstrate

  • Candidates must pass the Physical Test Battery or a specialized Technical Test before proceeding
  • Depth in Behavioral Interviewing (STAR Method)

How to prepare

  • Answer aloud and timed: Describe a safety hazard or risk you noticed in your previous workplace. What immediate actions did you take to resolve it?
  • Answer aloud and timed: How do you define a "culture of safety" within a software engineering team?
PG&E Software Engineer candidate reports ↗
02

Structured Panel Interview

reported

Candidates participate in a structured panel interview with two to five interviewers, following a pre-scripted list of questions.

What to demonstrate

  • Candidates participate in a structured panel interview with two to five interviewers, following a pre-scripted list of questions
  • Depth in Behavioral Interviewing (STAR Method)

How to prepare

  • Answer aloud and timed: Tell us about a time when you had to stop work on a project because of a potential risk or compliance issue.
  • Answer aloud and timed: How do you balance the pressure of meeting tight deadlines with maintaining strict safety and quality standards?
PG&E Software Engineer candidate reports ↗

PracHub editorial advice for the preparation topics above.

01

Prepare your safety story in advance

You will be asked about safety. Have a compelling, real-world example ready of a time you identified a risk (physical or digital) and took action to resolve it.

02

Do not skip steps in the STAR method

PG&E panel members are often grading you on a structured rubric that specifically looks for Situation, Task, Action, and Result. Clearly label these parts of your story as you speak.

03

Brush up on basic math

If your role requires the PTB exam, practice mental math, fractions, decimals, and long division. Not having a calculator can catch many modern software engineers off guard.

Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.

12 technical prompts0 include a worked solution

Merge partitioned event streams into one ordered feed with bounded lateness

hard
k-way mergewatermarksout-of-order streams

The read-model service consumes 64 log partitions carrying about 4,000 events per second in total. Each partition is ordered within itself, but partitions drift by up to 30 seconds, and the activity feed must present a tenant's events in occurred_at order. Produce the merge. State its complexity, the buffer it requires in events and in bytes, what happens when one partition is idle, and what you do with an event that arrives after you have already emitted its position. Payloads average 1 KB.

Approach
  1. Merge with a min-heap over the 64 partition heads keyed on (occurred_at, event_id): O(log P) per event and O(n log P) overall. The tie-break on event_id is what makes the output deterministic when two partitions carry the same millisecond, which matters because the feed is paginated and a non-deterministic order reorders pages under the reader.
  2. Emitting the heap head is only correct once every partition has produced everything up to that timestamp, so the emit condition is a watermark: the minimum across partitions of the highest occurred_at seen, less the allowed lateness. Events are held until the watermark passes them, which is what turns individually ordered streams into a jointly ordered one.
  3. Size the buffer from the lateness rather than guessing: 4,000 events per second times 30 seconds is 120,000 buffered events, and at 1 KB each about 120 MB of heap. That number is the real price of the ordering guarantee and belongs in front of whoever asked for it.
  4. Handle the idle partition explicitly, because it fails the feed rather than corrupting it: a partition with no traffic never advances its own maximum, so the watermark freezes and output stops entirely. Either every partition emits a periodic idle marker carrying the broker's current time, or the watermark falls back to wall clock for a partition silent beyond a threshold.
Follow-up
  • The lateness budget is raised to five minutes. What is the new buffer, and what besides memory changes?
  • The consumer restarts. Where does it resume from, and what does the feed look like for the first 30 seconds?

Canonicalise a request body into a stable idempotency fingerprint

medium
parsingcanonicalisationhashing

idempotency_key.request_fingerprint is a SHA-256 over the method, path and canonicalised body, and a retry whose fingerprint differs must be rejected with 422 rather than served the stored response. Write the canonicaliser. Bodies are JSON up to 256 KB nested at most 32 levels; clients vary key order, whitespace and unicode escaping, and some send 64-bit ids as JSON numbers. Produce a deterministic byte string such that semantically identical bodies match and any semantic difference does not. State your complexity and name two normalisations you refuse to perform.

Approach
  1. Parse once into a tree, then re-serialise under fixed rules: object keys sorted, array order preserved, one escaping convention, no insignificant whitespace. Parsing is O(n) and sorting keys is O(k log k) per object, so O(n log n) overall with O(depth) stack, and the 32-level cap is enforced during parsing because hostile nesting is how a canonicaliser becomes a stack overflow.
  2. Sort keys by their UTF-8 bytes and say why the obvious implementation is wrong in some runtimes: a default string comparison that orders by UTF-16 code units places surrogate pairs, meaning code points from U+10000 up, below U+E000 to U+FFFF, which is not UTF-8 byte order, so two services written in different languages disagree on the same document.
  3. Do not re-encode numbers through a double. IEEE-754 binary64 represents integers exactly only up to 2^53, so normalising a 19-digit id through a float changes it, and 1 against 1.0 cannot be reconciled without deciding whether they are the same value. Preserve the literal token, and require ids as strings at the API boundary if you want them comparable.
  4. Reject duplicate keys rather than picking one. JSON permits them and parsers disagree, most keeping the last, so any choice you make ties the fingerprint to a parser detail that the code handling the request does not necessarily share.
Follow-up
  • A client sends the same logical request with an extra field your API ignores. Same key, different fingerprint, so you return 422. Is that the right answer?
  • Where does the fingerprint get computed relative to request decompression and the body-size limit?

Archive a resource graph without breaking live references or recursing

medium
graph traversaltopological ordertenant isolation

Resources reference other resources within a tenant; for the largest tenant the reference table holds up to 2,000,000 nodes and 8,000,000 edges. Archiving a resource must archive everything reachable from it that nothing outside the set still references, refuse when a live external referrer exists, and terminate when references form cycles, which they legitimately do. Produce the archive order and the refusal list, targeting O(V+E). Say what stops the traversal crossing a tenant boundary, and why recursion is the wrong control structure at this size.

Approach
  1. Load the subgraph with the tenant predicate on both endpoints of the edge, not only on the side you started from. Scoping the left table alone is the classic cross-tenant leak: one mis-entered edge then pulls another tenant's resources into the traversal and, worse, into the archive.
  2. Traverse iteratively with an explicit stack. A 2,000,000-node graph can hold a chain deep enough to exhaust a native stack in the low tens of thousands of frames, and that failure is a process crash rather than an error you can return.
  3. Treat cycles as data rather than corruption: compute strongly connected components with Tarjan in O(V+E) using its own explicit stack, then condense. The condensation is a DAG, so a topological order over it gives the archive order, and every member of a component archives in one transaction because no order within a cycle is valid.
  4. Decide refusals with reverse edges. A candidate is archivable only if every in-edge originates inside the candidate set, so build the transpose or count in-degrees restricted to the visited set, and emit each blocked resource with the id of the external referrer, which is the only part of the answer an operator can act on.
Follow-up
  • The graph is read in one query and the archive writes a minute later. What can change in between, and how do you make the write safe?
  • The candidate set is 400,000 resources. Is that one transaction, and if not, what does a half-finished archive look like to a reader?

Built from the rounds and topics PG&E candidates report.

Small steps. Visible outcomes.0 / 7 completed
ONE WEEK · YOUR PACE

Prepare, practise & reflect

One practical outcome each day. Spend longer where you need it.

0 / 7 done
01Map the PG&E loop
  • Write out the reported sequence: Pre-employment Tests, Structured Panel Interview.
  • For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.

Deliverable: A one-page map of the 2 reported rounds, with the weakest marked.

02Work Behavioral Interviewing (STAR Method)
  • Spend the session on Behavioral Interviewing (STAR Method), which PG&E candidates report being tested on.
  • Write one worked example in Behavioral Interviewing (STAR Method) and time yourself on it.

Deliverable: One timed worked example in Behavioral Interviewing (STAR Method).

03Work Safety Practices / Safety Emphasis
  • Spend the session on Safety Practices / Safety Emphasis, which PG&E candidates report being tested on.
  • Write one worked example in Safety Practices / Safety Emphasis and time yourself on it.

Deliverable: One timed worked example in Safety Practices / Safety Emphasis.

04Work Power Systems Engineering
  • Spend the session on Power Systems Engineering, which PG&E candidates report being tested on.
  • Write one worked example in Power Systems Engineering and time yourself on it.

Deliverable: One timed worked example in Power Systems Engineering.

05Answer out loud: Safety and Compliance
  • Answer aloud, timed: Describe a safety hazard or risk you noticed in your previous workplace. What immediate actions did you take to resolve it?
  • Answer aloud, timed: How do you define a "culture of safety" within a software engineering team?

Deliverable: Spoken answers to 2 reported Safety and Compliance question(s), under time.

06Answer out loud: Structured Behavioral (STAR Method)
  • Answer aloud, timed: Tell me about a time when you and a coworker did not see eye to eye. How did you resolve the conflict and reach a conclusion?
  • Answer aloud, timed: Describe a situation where you realized you were not going to meet a project deadline. What did you do, and what was the outcome?

Deliverable: Spoken answers to 2 reported Structured Behavioral (STAR Method) question(s), under time.

07Answer out loud: Systems, Infrastructure, and Engineering
  • Answer aloud, timed: How would you build out an application and push it across multiple clients in a hybrid Windows environment?
  • Answer aloud, timed: Walk us through your experience writing scripts to automate system deployments or infrastructure configuration.

Deliverable: Spoken answers to 2 reported Systems, Infrastructure, and Engineering question(s), under time.

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Behavioural rounds judge the decision you made and what it cost.

Tell us about a time when you had to stop work on a project because of a potential risk or compliance issue.

medium
Safety and Compliance

Tell us about a time when you had to stop work on a project because of a potential risk or compliance issue.

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Tell me about a time when you and a coworker did not see eye to eye. How did you resolve the conflict and reac

medium
Structured Behavioral (STAR Method)

Tell me about a time when you and a coworker did not see eye to eye. How did you resolve the conflict and reach a conclusion?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a situation where you realized you were not going to meet a project deadline. What did you do, and wh

medium
Structured Behavioral (STAR Method)

Describe a situation where you realized you were not going to meet a project deadline. What did you do, and what was the outcome?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Explain a time when a project or deployment did not turn out as planned. What did you learn, and how did you p

medium
Structured Behavioral (STAR Method)

Explain a time when a project or deployment did not turn out as planned. What did you learn, and how did you pivot?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Describe a difficult interaction you had with a customer or internal stakeholder and how you resolved it.

medium
Structured Behavioral (STAR Method)

Describe a difficult interaction you had with a customer or internal stakeholder and how you resolved it.

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Why do you want to work for PG&E, and how do you see your skills aligning with our corporate values?

medium
Structured Behavioral (STAR Method)

Why do you want to work for PG&E, and how do you see your skills aligning with our corporate values?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

Walk us through your experience writing scripts to automate system deployments or infrastructure configuration

medium
Systems, Infrastructure, and Engineering

Walk us through your experience writing scripts to automate system deployments or infrastructure configuration.

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?

What is your experience with power systems analysis, load flow, or utility-specific software integration?

medium
Systems, Infrastructure, and Engineering

What is your experience with power systems analysis, load flow, or utility-specific software integration?

Approach
  1. Pick a story where you made the decision, not one where you watched it.
  2. State the situation in two sentences and spend the rest on the reasoning.
  3. Give the blast radius: what could have broken, and what you measured.
  4. Name the disagreement and how you resolved it with evidence.
Follow-up
  • What would you do differently if you ran that again?
  • How did you know your change caused the improvement?
  • 01

    Tell us about a time when you had to stop work on a project because of a potential risk or compliance issue.

  • 02

    Tell me about a time when you and a coworker did not see eye to eye. How did you resolve the conflict and reach a conclusion?

  • 03

    Describe a situation where you realized you were not going to meet a project deadline. What did you do, and what was the outcome?

  • 04

    Explain a time when a project or deployment did not turn out as planned. What did you learn, and how did you pivot?

PracHub preparation framework ↗
How technical are the software engineering interviews at PG&E?

The technical depth varies significantly by team. Some interviews focus almost entirely on behavioral questions, system architecture, and scripting logic, with no actual live coding. Other teams may require a basic coding assessment or domain-specific technical questions related to power systems, PLCs, or infrastructure deployment.

PG&E Software Engineer candidate reports ↗
What is the pre-employment testing process?

For many roles, you must pass the PTB (Physical Test Battery) and a Technical test before interviewing. The PTB tests basic math (without a calculator), while the Tech exam covers basic physics, diagram reading, and logical word problems. These are designed to ensure foundational analytical competency.

PG&E Software Engineer candidate reports ↗
How important is the STAR method in the interview?

It is absolutely critical. PG&E interviewers use standardized scorecards provided by HR. If you do not structure your answers using the STAR format (Situation, Task, Action, Result), the panel will have difficulty grading your responses, which can significantly lower your overall score.

PG&E Software Engineer candidate reports ↗
What is the company culture like for software engineers?

The culture is highly structured, collaborative, and stability-focused. Because the work involves critical public infrastructure, there is a strong emphasis on compliance, safety, and thorough planning over the "move fast and break things" mentality common in consumer tech.

PG&E Software Engineer candidate reports ↗
Does PG&E hire contractors, and what is that process like?

Yes, PG&E hires a significant number of software engineers and analysts as contractors through external agencies. The interview process for contract roles is typically faster, often consisting of a single interview with the hiring manager rather than a full panel.

PG&E Software Engineer candidate reports ↗
What topics does PG&E test in interviews?

PG&E interviews most often cover Behavioral Interviewing, Stakeholder Management, Panel Interviewing, Project Management, and STAR Method (Situation, Task, Action, Result). The exact emphasis depends on the specific role you apply for.

PG&E Software Engineer candidate reports ↗
Sources & methodology 3 sources ↗

No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.