Software Engineer, Platform / Applied AI (Full-Stack)

davidjoseph-co; San Francisco (CA); On-site; USD 180,000 - 220,000; Full time

Benefits offered by this job

Competitive salary + equity (4-year)

Daily lunch & dinner

Gym membership

Health insurance

Job summary

AfterQuery is seeking a core/founding Software Engineer to build the data infrastructure for frontier-model development. You’ll own projects end-to-end across frontend, backend, and infrastructure in a fast-moving startup.

You will influence product strategy, ship features rapidly, and help shape a scalable platform while benefiting from competitive salary and equity. On-site in San Francisco with strong backing and rapid growth opportunity.

Qualifications

• Proficiency in JavaScript (Next.js) and Python, with demonstrated full-stack experience.
• Experience with serverless/cloud functions for heavy data processing (GCP/AWS).
• Hands-on with Redis (caching) and Elasticsearch (indexing) for scalable pipelines.
• Background in AI research, LLM evaluation, or human-in-the-loop systems.
• Founding engineer experience or strong production track record.

Responsibilities

• Build and scale data infrastructure spanning frontend, backend, and infra.
• Architect and optimize high-throughput data pipelines under heavy load.
• Collaborate with the founding team to define product strategy and ship features quickly.
• Set engineering best practices and lay groundwork for future team growth.

Skills

JavaScript/Next.js

Python

TypeScript

Go

Distributed systems

Production experience

AI/LLM background

Education

Top university (US/Canada/UK)

Tools

Next.js

TypeScript

Python

Go

GCP/AWS

Kubernetes

Redis

Elasticsearch

Kafka/RabbitMQ

Job description

AfterQuery — Software Engineer, Platform / Applied AI (Full-Stack)

Type: Full-time | On-site | San Francisco, CACompensation: $180,000–$220,000 + Competitive equity (4-year vest)Hiring count: 4Visa sponsorship: O-1, OPTReports to: Interviews run by Alec (Initial Screen) and an engineer (Second Round); founding-team reporting line — confirm

About AfterQuery

AfterQuery is a research lab investigating the boundaries and capabilities of AI through novel datasets and experimentation. Its customers are the foundation-model labs — it serves the frontier AI labs. Backed by top investors including Y Combinator and BoxGroup, ex-partners from Lightspeed and Index Ventures, and senior leadership at Google DeepMind and Meta GenAI. The founding team brings backgrounds from Jane Street, Meta, Citadel Securities, Google, Goldman Sachs, Morgan Stanley, Silver Lake, Berkeley AI Research (BAIR), and the Stanford AI Laboratory (SAIL). Reported $25M+ annualized revenue and one of the fastest-growing companies in its YC batch.

Founded: 2025 | Team size: 11–50 | Stage: Series A (company card) — outreach describes it as "seed-stage"; confirmIndustry: AI research / data infrastructure for frontier labsWebsite: afterquery.comOffice: San Francisco, CA

Why Candidates Should Join

• Founding ownership: One of the first hires; own entire projects end-to-end and define/own the data infrastructure from day one, with immediate visible impact.
• Frontier impact: Build the data infrastructure shaping frontier-model development, with the frontier AI labs as direct customers.
• Trajectory & backing: One of the fastest-growing companies in its YC batch, $25M+ annualized revenue, elite founding team and investors, with a path to lead and grow an engineering team as they scale.
• Comp & perks: Competitive salary + equity (4-year vest), daily lunch & dinner covered, free gym membership, health insurance.

The Role

As a core/founding engineer, you’ll build the data infrastructure shaping frontier-model development, owning projects end-to-end across frontend, backend, and infrastructure.

What You’ll Be Doing

• Build and scale complex data-capture workflows across web (Next.js) and desktop (Python)
• Architect and optimize high-throughput data pipelines under heavy load
• Collaborate with the founding team to define product strategy and ship features fast
• Set engineering best practices and lay the groundwork for future team growth

Tech stack: Next.js / JavaScript / TypeScript, Python, Go · GCP/AWS (serverless, cloud functions) · Kubernetes · Redis · Elasticsearch · Kafka / RabbitMQ · NoSQL · APIs

Required Qualifications (role body)

• Proficiency in JavaScript (Next.js) and Python, with demonstrated experience building full-stack web applications
• Experience with serverless architecture and cloud functions for heavy data processing (GCP/AWS)
• Storage, caching & search: hands-on with Redis (caching), Elasticsearch (indexing), and message queues (Kafka/RabbitMQ) to build scalable, low-latency pipelines
• Any background in AI research, LLM evaluation, or human-in-the-loop systems
• Experience getting your ideas into production (founder experience preferred)

Requirements

• Must come from a top university (US/Canadian/UK), top quant firm, or have founding engineer experience.
• Strong coding fundamentals in Node.js / TypeScript, Python and/or Go.
• Deep understanding of distributed systems, scalability challenges, and system design.
• Familiarity with cloud platforms (GCP/AWS), Kubernetes, APIs, NoSQL databases.
• Ability to reason about trade-offs and balance speed vs reliability.
• Strong communication skills and a bias toward ownership, curiosity, and delivering simple solutions to complex problems.
• Bonus: Experience with RL environments, agentic systems, or human-in-the-loop workflows.

Role Details

Salary$180,000–$220,000EquityCompetitive (4-year vest)Experience0–4 yearsOn-site policyOn-site, San FranciscoVisa sponsorshipO-1, OPTEmployment typeFull-timeLocationSan Francisco, CAOpenings4