Senior Backend Engineer, Nitro

Blockchain Lab analysis

Senior backend on Nitro, the software under Arbitrum. The Lever record was created on 17 April 2025 and was still open on 6 October 2026. Pay is not disclosed. ARB is not your equity.

Ninety days — illustrative

Not the employer’s onboarding plan.

1. Days 1–30: build the client they actually run. Find the hot path.
2. Days 31–60: one performance or correctness change with a benchmark.
3. Days 61–90: a review comment you were willing to block a release for.

A week you can rehearse

• Explain a concurrency bug you have shipped a fix for.
• Say what WASM changes about a fault.
• Ask who still owns this req.

Ask them

• Is the April 2025 req still a team?
• What is cash compensation?
• Is any part of pay denominated in ARB? If they say yes, ask why.

Walk away if

• They cannot show a repo, even privately.
• The job has become ZeroDev key management without a title change.
• Compensation is the token.

Proof you can build before you apply

• The state-machine lab. Honest path, one adversarial case.

• Protocol atlas
• Canon

Blockchain Lab analysis

Public reporting and the employer’s own releases. Not a relationship with Blockchain Lab. Not a credit opinion.

Founded

2018. Steven Goldfeder is the chief executive. Harry Kalodner and Ed Felten are the co-founders the company's technical history is told through.

Base

Both seats say Remote. Neither says worldwide.

Status

Private. The posting says backed by $124 million. That is the employer's sum, not a fresh round.

People

The ZeroDev acquisition closed into this company on 13 August 2025. Price not disclosed.

1. On the posting

   Employer's own sum

   $124 million

   The Lever text says the company is backed by $124 million. This brief does not add a newer priced round on top of that sentence. Historical Series A and Series B figures circulate in databases. They are not repeated here as if this desk re-read the closes.

2. 13 Aug 2025

   Acquisition of ZeroDev

   Not disclosed

   Offchain's release: strategic acquisition of ZeroDev, terms not disclosed. ZeroDev's own note says the product keeps supporting many chains, not only Arbitrum. The wallet seat exists because of this deal.

• Stale Nitro req. Created April 2025. Confirm it is alive.
• Undisclosed acquisition price. ZeroDev equity, if you had any, is already a story. New hires do not inherit it.
• Remote without a country list.
• Token confusion. ARB is not Offchain stock.

Ask them

• Is the Nitro seat a 2025 req that nobody closed, and who would you report to?
• What of ZeroDev is still the roadmap versus what was acqui-hired?
• Which countries can the remote contract actually employ?
• Is any compensation denominated in ARB?

• Offchain release on ZeroDev, 13 Aug 2025
• ZeroDev's note on the acquisition

If a figure is not in those sources, it is not in this brief on purpose.

Employer stated. Senior backend engineer on Nitro, the core of Arbitrum. Concurrency, WebAssembly, and security-minded systems work. The Lever record was created in April 2025 and was still listed on 6 October 2026.

• As part of the Nitro Backend team at Offchain, you will work on the core infrastructure powering Arbitrum, the leading Ethereum scaling solution. In this role, you’ll tackle complex distributed systems challenges, optimize performance, and contribute to the security and scalability of Arbitrum.
• You’ll collaborate closely with our research, product, and blockchain engineering teams, working at the cutting edge of blockchain technology alongside world-class engineers, including many industry leaders.
• Possess extensive production experience with a programming language that supports concurrency (e.g. Go, C++, or Rust)
• Familiarity with WebAssembly, particularly writing high performant and high security code in production environments
• Experience working with compilers, architecting systems and developing SDKs

Source: the employer’s public Lever record, job 82c41afd-b4be-40d2-8bc2-3f299ced3c4a. Open the original. First seen by this desk 2026-10-06. Nothing above the fold is a substitute for that page.

Blockchain Lab analysis. These lines are a reading of the advertisement. They are not extra hiring requirements.

• Ask whether Nitro still needs this seat or the req survived a reorg.
• ARB is the DAO token, not your equity.
• Bring a concurrency bug you found in production, not a tutorial.

• Anything the compensation line does not already quote. A printed band is the employer’s sentence for the place they named — not a Blockchain Lab estimate, and not a promise for every location on the posting.
• A later edit date. Lever exposed when the posting was created, not when it was last refreshed.
• Which countries may apply. “Remote” alone is not worldwide eligibility. If the employer wrote a country or a region, that sentence is theirs — still ask which entity can hire you.
• Visa sponsorship, the real on-call rota, and the employing subsidiary, unless the posting already named them.