Senior Frontend Engineer
About Notabene
Notabene is focused on integrating crypto into everyday economic activities. The team, spanning across three continents and eight countries, supports a diverse customer base of over 100 organizations ranging from financial institutions to fintechs and exchanges. Notabene's founders have been pioneers in developing Self Sovereign Identity protocols. This technology plays a crucial role in the company's advanced tech stack.
The company has garnered investments from reputable firms such as Y Combinator, Jump Capital, and Castle Island, indicating its strong growth trajectory.
About The Role
The Senior Frontend Engineer position at Notabene empowers you to revolutionize how people conduct daily transactions using stablecoins. You will play a vital role in advancing and maintaining essential embedded Payments UI components that facilitate compliance procedures in customer payment processes. Your responsibilities will include gathering additional user information to ensure secure transactions, interacting with a wide range of web3 and hardware wallets.
In this role, you will utilize Svelte and various mobile development frameworks like React Native to create a seamless user experience across web and mobile platforms. Collaborating closely with product, security, and platform teams, you will introduce new features to the market.
Key Responsibilities
- Utilize strong Web3 expertise to understand both current and evolving payment use cases.
- Ensure secure and compliant data handling within the Payments UI to safeguard sensitive data and engage with crypto wallets.
- Work collaboratively with product, design, security, and platform teams to align Payments UX functionality with the Notabene platform.
- Advocate for frontend development best practices and security protocols to maintain high technical standards in embedded applications.
What you bring to Notabene
Over 7 years of frontend development experience with a focus on developing embedded UI components for payments, web3, or secure applications.
Expertise in Web3 technology including cryptography, public/private key encryption, and familiarity with decentralized identity solutions.
Proficiency in Svelte and React/React Native and experience in optimizing components for web and mobile platforms.
Sound knowledge of web security, PII handling practices, RESTful APIs, web sockets, and event-driven data flows.
Strong problem-solving skills, attention to detail, and the ability to work autonomously in a global, remote-first environment.
Excellent communication skills to collaborate effectively across various teams and departments.
If you believe you are a suitable candidate for this role, we encourage you to apply regardless of your blockchain experience. Notabene promotes diversity and inclusion and does not discriminate based on various factors including race, gender, age, sexual orientation, or veteran status.
Junior AI Engineer
Join one of our fast-growing portfolio startups and help build simple AI features. You’ll work with large language models, create basic automations and chat tools, test ideas, fix small bugs, and integrate AI into everyday products.
Skills & Requirements:
0–2 years of experience (fresh graduates or self-taught welcome)
Basic Python knowledge
Interest in AI, LLMs or chatbots (personal projects are a big plus)
Quick learner who enjoys trying new things
Good English for team communication
Salary: $95,000 – $135,000 USD base + equity in the startup + full benefits
Description:
Sirex.vc not only invests — we actively help our portfolio companies hire great people. This Junior AI Engineer role is inside one of our AI-native startups. You’ll get real hands-on experience, learn from the best, and build things users actually use — all with full support from the Sirex team.
High risk. Zero apologies.
AI Agent Engineer
Join one of our high-conviction AI-native portfolio companies and build autonomous AI agents from the ground up. You’ll design agent architectures, implement tool-calling & memory systems, connect them to browsers/shell/APIs, run long-horizon tasks, and ship features that make the product feel alive and truly useful.
Skills & Requirements:
2–5 years building LLM-powered agents (LangGraph, CrewAI, ReAct, custom frameworks)
Strong Python skills + experience with tool calling, RAG, vector stores and evaluation
Bonus: familiarity with browser automation, self-hosted models or decentralized compute
Fast executor who loves shipping in ambiguity
Passion for agents that actually do real work (not just chat)
Salary: $160,000 – $230,000 USD base + meaningful equity (in the portfolio company) + full benefits + carry from Sirex network
Description:
Sirex.vc doesn’t only write checks — we actively help our portfolio companies recruit the best people on the planet. This AI Agent Engineer role is inside one of our fastest-moving startups building the next generation of autonomous agents. You’ll get direct support, intros, and operational help from the Sirex team while working on frontier technology that can change how the world uses AI.
High risk. Zero apologies.
Investment Analyst
Help the team find and evaluate early-stage startups. Search for promising projects, do quick market checks, prepare short summaries, track portfolio companies, and assist with basic due diligence.
Skills & Requirements:
0–2 years of experience (recent graduates or startup background welcome)
Strong interest in AI, crypto, and new technologies
Good at research, writing clear notes, and using spreadsheets
Organized, fast learner, and comfortable with uncertainty
English at upper-intermediate level
Salary:
$85,000 – $115,000 USD base + small carry + full benefits
Description:
At Sirex.vc we back crazy ideas in AI and decentralized tech. As Investment Analyst you’ll be right in the middle of the action — scanning hundreds of startups every week, learning how real venture works, and helping decide where we put money. Perfect first step into VC for someone hungry and smart. High risk. Zero apologies.
Operating Partner
Work side-by-side with portfolio founders to scale their companies at speed. Lead talent acquisition for critical roles, build operational systems and processes, shape go-to-market strategy, track key metrics, and support follow-on fundraising.
Skills & Requirements:
4–6+ years of hands-on experience in high-growth startups (previous Head of Operations, Chief of Staff, or founding team member strongly preferred)
Deep understanding of AI, decentralized infrastructure or developer platforms
Strong talent network and proven ability to recruit top technical talent
Exceptional execution skills and comfort operating in ambiguity
Data-oriented and systems thinker
Salary:
$175,000 – $245,000 USD base + significant carry + equity + full benefits
Description:
Sirex.vc doesn't just invest — we build alongside our founders. As Operating Partner, you will be the difference-maker for our portfolio companies, rolling up your sleeves to help them move faster and smarter than their competition. If you live for turning chaos into momentum and want to help create the defining companies of the next decade, this is your role. High risk. Zero apologies.
Venture Associate – AI & Decentralized Infrastructure
Source, diligence, and close early-stage investments in AI-native technologies, decentralized protocols, developer platforms, and compute infrastructure. Work side-by-side with founders post-investment on strategy, hiring, product roadmap, and scaling operations.
Skills & Requirements:
2–4 years in venture capital, startup operations, or technical role (engineering/product background strongly preferred)
Deep understanding of AI models, blockchain infrastructure, open-source ecosystems, and compute markets
Proven ability to build founder networks and spot asymmetric opportunities early
Exceptional analytical skills, written/verbal communication, and comfort with high-uncertainty decisions
Self-starter who moves fast and doesn’t need hand-holding
Salary:
$150,000 – $220,000 USD base + meaningful carry + equity upside + full benefits
Description:
Sirex.vc backs visionary founders redefining the open digital economy with asymmetric, high-conviction bets. We move at startup speed and expect the same from our team. As Venture Associate you’ll be on the front lines hunting the next 100x opportunities in AI, crypto infra, and compute — while rolling up your sleeves to help portfolio companies win. High risk. Zero apologies. If you live for the thrill of early-stage tech and want to build the future instead of just funding it, we want to talk.