Senior Blockchain Security Developer (Canton)

Blockchain Lab analysis

Build OpenZeppelin's Daml contracts library for Canton, while the company has agreed to be bought by S&P. Not the Ethereum audit practice. Not the Solana principal seat. Pay is not disclosed.

Ninety days — illustrative

Not the employer’s onboarding plan.

1. Days 1–30: ship nothing. Read the CIP you would implement and the Daml you would extend.
2. Days 31–60: one library feature with an audit note.
3. Days 61–90: a design you defended in front of a partner who can say no.

A week you can rehearse

• Explain a Daml choice and who must sign it.
• Say what you would not put in a public reference implementation.
• Ask whether the offer is pre-close or post-close.

Ask them

• Has the S&P deal closed, and who is the employer on the contract?
• Which reference app is actually staffed this year?
• What happens to unvested equity, and is there a retention grant?

Walk away if

• They cannot say whether you are on the library or on billable reviews.
• Daml experience is 'optional for the right Solidity person' after the posting said fluency.
• Pay is a token. The posting did not say that.

Proof you can build before you apply

• The security-review lab, aimed at a library change. Do not audit a client.

• Failure atlas
• Canon

Blockchain Lab analysis

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

Founded

2015, in Buenos Aires, as Zeppelin.

Base

Distributed. One posting says Remote - Worldwide. The other says Remote. Those are not the same sentence.

Status

Private, with a merger announced. S&P Global said on 17 September 2026 it had agreed to acquire the company. PitchBook marked the deal as announced, not as a closed integration.

People

PitchBook listed about 140 employees. Demian Brener remains CEO under the announced structure.

1. 2015–2018

   Early venture

   Not reliably public

   Databases list seed and Series A activity, including Fabric, BlueYard, Collaborative Fund, and True Ventures among historical investors. Amounts are paywalled or missing. We do not fill them in.

2. Mar 2023

   Later-stage VC

   Undisclosed

   PitchBook records a completed later-stage round. No post-money we will quote.

3. 17 Sep 2026

   Agreement to be acquired

   Undisclosed

   S&P Global said the deal is not expected to be material to its results. That sentence is aimed at S&P shareholders. For you it means the price was not large relative to S&P, not that your unvested equity is safe or worthless. Ask counsel.

• Deal not described as closed in every database. Your offer may be pre-close or post-close. The benefits, the option plan, and the employer of record change across that line.
• Undisclosed price. You cannot value an option against a blank.
• Services culture inside a public parent. Utilisation, conflicts, and a slower ship cycle are the ordinary result. Sometimes that is what you want.
• Solana versus the Ethereum brand. A principal seat on Solana can be a growth bet or a rounding error. Get it in writing.

Ask them

• Has the S&P transaction closed, and who is the employer of record on the offer?
• What happens to unvested equity, and is there a retention grant?
• Does Security Services stay independent of Ratings engagements?
• For Solana: is the library a funded roadmap or a single seat?
• Worldwide remote, on the researcher posting, means which employment entities and which tax setups?

• S&P Global announcement, 17 Sep 2026
• PitchBook company profile
• What the deal changes for builders

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

Employer stated. Senior blockchain security developer on OpenZeppelin’s Canton library: Daml contracts, reference implementations, and CIP standards with Digital Asset. Not the Ethereum audit practice and not the Solana principal seat.

• Own features of the OpenZeppelin Contracts Library for Daml end to end, from design through audit: examples include a Timelock, access control, vaults, or token standard support.
• Design and implement components of the year-1 Reference Implementations: privacy-preserving DEX, lending protocol, cross-chain stablecoin settlement, and confidential auction launchpad.
• Implement and shepherd the OZ Daml versions of CIP-56, CIP-86, CIP-103, future CIPs. Coordinate with Digital Asset on spec evolution and with ChainSafe on middleware alignment.
• Present and defend your designs in technical discussions with Digital Asset, the Canton Foundation, and other partners.
• Work with OpenZeppelin's security researchers on threat models, audit preparation, and fixes for the components you own.

Source: the employer’s public Greenhouse record, job 7742510003. 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.

• If you cannot explain what a Canton party sees, you are not this hire.
• The buyer is S&P. Ask whether a Canton library is a product or a slide.
• Privacy in the posting means selective disclosure, not anonymity.

• 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.
• Closing date, and the day the role was first published. The board timestamp is an update.
• 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.