Block interview, Square and Cash App pair programming.

Square's careers page names the pair-programming task and says interviews are virtual. The rest of the loop comes from candidate reports and interviewing.io; levels and teams vary it, and interns and data scientists get their own versions.

Pair programming is Block's signature round, from Square's earliest engineering hires to Cash App today. You get one problem in CoderPad, delivered in parts, and an engineer pairs with you the whole time. Square's engineering blog explained why it started: engineers type code into an editor rather than write it on a board, and pairing shows code structure, testability and maintainability. Here is what candidates report and how to take each part.

• The problem comes in parts: A candidate on Blind reached part four of four in one screen; another describes the next part as 'ok now make it sorted'. Write the first part so the next one is an addition: small functions, clear data structures, no clever shortcuts you will have to undo.
• Explaining is graded: A Square engineer wrote that communication is a big part of the interviews, and that a candidate who struggled and didn't explain their changes well may be asked for a second screen. Say what you are about to do, why, and what you are changing when you change it.
• Practical over puzzles: interviewing.io describes the coding as practical, giving the example of an app to split a bill with friends, and a reported phone screen asked for nearby points in a JSON array. Practise small, realistic tasks with a follow-up, not only algorithm puzzles.
• Get it working, then make it fast: In the reported coordinates problem, the efficient version came as the follow-up. Ship a correct simple version first, say its cost out loud, then improve it.
• Don't go down one path for too long: The candidate who reached part four said they lost time going down one approach in part two before switching. If an approach stalls, say so and change course; the interviewer is pairing with you.

Practise one multi-part problem end to end in 60 minutes, out loud, with someone adding a requirement every 15 minutes. That is the round.

Block doesn't publish a list of interview values. What its own pages and candidate reports say the loop looks for:

• Practical code: structure, testability and maintainability, the reason Square's engineers started pair interviewing
• Explaining your reasoning as you code
• Code that extends cleanly when the next part of the problem arrives
• Real projects you can talk about in depth
• AI fluency, named in Block's 2026 engineering ads

Candidates report the coding problems as multi-part tasks: a first part that works, then a requirement that changes it. The rest of the loop asks about your past work.

Base salary ranges posted on Block's job board in September 2026; Zone A covers the highest-cost US areas, and lower zones pay less. Equity comes on top, as Block stock. Levels.fyi medians for total pay read on 1 October 2026: about $241K at L4, $301K at L5 and $426K at L6.

1. Practise multi-part coding problems out loud in CoderPad, with someone adding a requirement every 15 minutes.
2. Solve the nearby-coordinates problem: the direct version first, then a grid of 10-by-10 cells.
3. Write code that extends: small functions and clear data structures, so the next part is an addition.
4. Prepare to talk about two real projects in depth: the hardest decision, who you worked with, what you'd change.
5. Have a payments design ready: a double-entry ledger, idempotent transfers and where fraud checks sit.
6. Bring an honest AI fluency story; Block's 2026 ads ask for it.

This guide covers Block's engineering loop across Square and Cash App. Data science, design and business roles have their own interviews; data scientists report a Python and SQL coding round. For management and leadership roles the loop is similar but the bar shifts to people, delivery and strategy, so pair it with the leadership interview prep hub. The bar for your exact role comes from the role-by-role guides, and the prep that actually transfers is spoken, so run a mock interview before the real one.

Also interviewing at HSBC, Goldman Sachs or Optiver? Their guides follow the same format, from the first screen to the offer.

• 01Square careers, interviews at Squarethe pair-programming task for engineering roles, virtual interviews, and preparing to talk about past projects.
• 02Square engineering blog, Why we pair interview (2011)why Square started pair interviewing and what it shows: code structure, testability, maintainability.
• 03Blind, Cash App 2nd pair programming interview (July 2023)a candidate reaching part four of four, and a Square engineer on communication and second screens.
• 04LeetCode, Square phone screen L4/L5 (November 2024)the nearby-coordinates problem from a JSON array and its efficiency follow-up.
• 05Blind, Cash App MLE ML pair programming round (December 2022)the ML pairing round: basic exploration, preprocessing and a model you can talk about.
• 06LeetCode, Block intern loop (April 2025)three separate 60-minute pair-programming interviews for interns.
• 07interviewing.io, Block interview questionsthe loop structure, practical coding over puzzle-style, and the system design hour.
• 08CNN, Block cuts staff by 40% (26 February 2026)more than 4,000 roles cut and Jack Dorsey's note on a smaller team.
• 09Block job boardabout 219 open postings on 1 October 2026, posted base ranges by zone, and AI fluency in engineering ads.
• 10Levels.fyi, Block software engineermedian total pay by level, read 1 October 2026.

Interview processes change. This reflects widely-reported and sourced conditions as of 2026 — confirm specifics with your recruiter, and treat it as a map rather than a guarantee.