[SF] Founding Engineer

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At Charcoal, we’re reinventing how we think about search in the agentic era. Search systems of yesterday were built for 1/ web search and 2/ humans clicking through documents. Tomorrow’s search systems will have a completely different user: agents. We’re building the best agentic search platform for private data, which makes up 90% of the world’s information.

We’ve raised $2.5m from investors and operators at Cursor, Plaid, Front, Yelp, Decagon, and more.

We’re looking for founding engineers who:

Ship with urgency
Embrace AI to its fullest potential (yes, let it rip)
But know when to step in: performance, reliability, and great developer experience

Our Culture

Life’s work**:** the best work of our careers so far—work we’ll be proud of for a decade, shaped by obsession with the details, a willingness to do hard things, and end-to-end ownership.

Everyone at Charcoal is here to do our life’s work. We’re a small team of low-ego, high-output individuals who value directness, strong opinions loosely held, and momentum.

We’re also fun people 😊

What You’ll Do

Build core product and infrastructure across the stack (from retrieval + indexing to APIs and UI)
Build evaluation + observability: relevance metrics, offline/online testing, and quality tooling for LLM/RAG systems
Build and adapt RL models for customer use cases, turning cutting-edge research into reliable product capabilities
Push forward research efforts through hands-on experimentation across models, systems, and product behavior
Raise our bar for engineering craft, help with recruiting, and hold the line on quality

Traits That Thrive at Charcoal

High Ownership - Ability to tackle ambiguity and take ownership of large, undefined problems
Obsession – A deep obsession with the customer, product, and the details.
Direct, accountable communication – Values clarity, speed, and ownership in communication
Low ego & relentless ownership – Takes full responsibility and follows through without excuses

Your Qualifications

N years of software engineering experience - we care about slope & output, not YOE
Experience building developer platforms - APIs (auth, rate limits, multi-tenant SaaS)
Strong engineering background - Traditional ML or math background (nice-to-have)
Systems experience - performance engineering, distributed systems, GPUs/CUDA (nice-to-have)

Our Benefits

Salary: $200k – $250k
Equity: 1–3%
Medical, dental, and vision insurance
Company-wide annual off-site
High ownership, high trust, and fast career progression alongside world-class partners
In-person culture with deep commitment to excellence

To apply, email [email protected] with your application. We look forward to hearing from you!