Senior Software Engineer - Special Projects
Status
Washington, USA
Full time
Remote
Compensation is not specified
Role
Software Engineer
Description
Circle is a dynamic financial technology firm positioned at the forefront of the evolving internet of money, facilitating global, near-instantaneous, and cost-effective value transfers. Through innovative technologies such as USDC, a blockchain-based dollar, Circle empowers businesses, institutions, and developers to leverage groundbreaking financial opportunities. The Ripple company ethos emphasizes core values including Multistakeholder, Mindfulness, Excellence, and High Integrity. Operating in a remote support environment, Circle cultivates a culture of collaboration, diversity, and agility, fostering creativity and sustainable growth.
Role Summary: Seeking an adept Smart Contract Engineer with profound expertise to play a pivotal role within Circle's USDC Smart Contract team. As a Senior/Staff Software Engineer within this team, you will spearhead the technical design and expansion of smart contracts for USDC across various blockchain networks, like Ethereum, Solana, and Cosmos.
Responsibilities include:
- Designing, coding, testing, and deploying smart contracts for secure and streamlined transactions.
- Improving existing smart contracts to enhance developer efficiency, safety, and overall performance.
- Implementing best security practices and performance optimization techniques.
- Performing risk evaluations associated with smart contract development, identifying vulnerabilities, and executing mitigation strategies for improved security and resilience.
Candidate Profile / Experience Level: Senior Software Engineer (III):
- Over 4 years of professional software development experience, comprising internships.
- A minimum of 2 years of dedicated smart contract development experience on blockchain platforms.
- Proficiency in programming languages applied in non-EVM smart contracts, such as Rust, Go, or similar.
- Hands-on experience with a primary non-EVM blockchain ecosystem like Cosmos or Solana.
- Proven track record in architecting, coding, testing, and deploying secure and efficient smart contracts.
- Strong focus on integrative security measures in smart contract development.
- Excellent problem-solving skills combined with a proactive and data-driven approach to challenges.
- Independent research capabilities to devise innovative solutions.
Staff Software Engineer (IV) requires all the criteria of a Senior Software Engineer and:
- More than 7 years of professional software development experience, including internships.
- At least 4 years of specialized smart contract development expertise on blockchain platforms.
- Mastery of non-EVM programming languages and technologies.
- Deep understanding of blockchain principles, technologies, and various blockchain & web3 protocols.
- Capacity to lead technical teams, mentor junior engineers, and effectively collaborate across functions.
- Excellent communication skills to facilitate consensus-building with team members and stakeholders.
Compensation and Benefits: Competitive base pay ranges (Senior: $147,500 - $195,000; Staff: $172,500 - $227,500), alongside attractive annual bonus targets. Additional offerings include equity, comprehensive medical, dental, vision coverage, 401(k) plans, and discretionary vacation policies. Ten paid sick days annually and eleven paid holidays offered in the U.S.
Circle ensures an inclusive workforce, refrains from discrimination based on race, religion, nationality, gender, age, marital status, veteran status, or disability, and adheres to the E-Verify Program where required by law for specific locations.
Skills Required
Circle
Website
www.circle.comCompany size
Not specified
Location
United States
Description
Not specified
Status
Sirex
Junior/Mid Decentralized Infrastructure Engineer
Full time
Remote
Role:
Help build and scale decentralized infrastructure: contribute to compute networks, protocols, storage layers, and orchestration tools that power AI agents and open digital systems. You’ll write code, run tests, fix bugs, and ship real features fast.
Skills & Requirements:
1–3 years in blockchain infra, distributed systems, or high-scale compute (or strong personal projects)
Solid Python / Rust / Go skills
Interest in libp2p, IPFS, GPU orchestration, or decentralized compute
Quick learner who ships clean code and loves performance/cost challenges
Salary:
$110,000 – $165,000 USD base + meaningful equity (portfolio startup) + full benefits + Sirex carry
Description:
Sirex.vc doesn’t just invest — we plug strong builders straight into our portfolio companies.
This is your chance to work on the real infrastructure behind autonomous agents and the open digital economy. Full support from the Sirex team, fast growth, zero bureaucracy.
High risk. Zero apologies.
Help build and scale decentralized infrastructure: contribute to compute networks, protocols, storage layers, and orchestration tools that power AI agents and open digital systems. You’ll write code, run tests, fix bugs, and ship real features fast.
Skills & Requirements:
1–3 years in blockchain infra, distributed systems, or high-scale compute (or strong personal projects)
Solid Python / Rust / Go skills
Interest in libp2p, IPFS, GPU orchestration, or decentralized compute
Quick learner who ships clean code and loves performance/cost challenges
Salary:
$110,000 – $165,000 USD base + meaningful equity (portfolio startup) + full benefits + Sirex carry
Description:
Sirex.vc doesn’t just invest — we plug strong builders straight into our portfolio companies.
This is your chance to work on the real infrastructure behind autonomous agents and the open digital economy. Full support from the Sirex team, fast growth, zero bureaucracy.
High risk. Zero apologies.
Payment in Crypto
Sirex
Senior Decentralized Infrastructure Engineer
Full time
Remote
Role:
Build and scale production-grade decentralized infrastructure: compute networks, protocols, storage layers, orchestration for AI workloads, and open-source primitives that power the next generation of agent systems.Skills &
Requirements:
4+ years in blockchain infra, distributed systems or high-scale compute
Deep experience with Rust / Go / C++ and protocols (libp2p, IPFS, custom consensus, GPU orchestration)
Bonus: self-hosted AI compute, decentralized training or edge inference
Ship fast, own uptime, love extreme performance and cost efficiency
Salary:
$175,000 – $255,000 USD base + big equity (portfolio startup) + full benefits + Sirex carry
Description:
Sirex.vc doesn’t just invest — we plug elite builders straight into our fastest portfolio companies.
This is your chance to build the actual rails for autonomous agents and open digital economy at scale. Zero bureaucracy, maximum leverage.
High risk. Zero apologies.
Build and scale production-grade decentralized infrastructure: compute networks, protocols, storage layers, orchestration for AI workloads, and open-source primitives that power the next generation of agent systems.Skills &
Requirements:
4+ years in blockchain infra, distributed systems or high-scale compute
Deep experience with Rust / Go / C++ and protocols (libp2p, IPFS, custom consensus, GPU orchestration)
Bonus: self-hosted AI compute, decentralized training or edge inference
Ship fast, own uptime, love extreme performance and cost efficiency
Salary:
$175,000 – $255,000 USD base + big equity (portfolio startup) + full benefits + Sirex carry
Description:
Sirex.vc doesn’t just invest — we plug elite builders straight into our fastest portfolio companies.
This is your chance to build the actual rails for autonomous agents and open digital economy at scale. Zero bureaucracy, maximum leverage.
High risk. Zero apologies.
Payment in Crypto
Sirex
Junior AI Engineer
Full time
Remote
Role:
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.
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.
Payment in Crypto
Sirex
AI Agent Engineer
Full time
Remote
Role:
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.
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.
Payment in Crypto
Sirex
Investment Analyst
Full time
Remote
Role:
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.
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.