---
title: 'Staff SW Engineer at fastino.ai'
canonical: 'https://feeny.ai/job/staff-sw-engineer-fastino-ai-san-francisco-rxxsvqvhbkm7'
type: 'job'
last_seen: '2026-10-31'
---

# Staff SW Engineer at fastino.ai

- **Company:** fastino.ai
- **Location:** San Francisco, CA
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-10-30
- **Last confirmed live:** 2026-10-31
- **Apply:** https://jobs.ashbyhq.com/fastino-ai/eea1163c-8f0e-4be3-a99b-502bd4e631cb

## Job description

Staff Software Engineer Full-time | San Francisco Introduction:

- Join us at Fastino as we build the next generation of LLMs. Our team, boasting alumni from Google Research, Apple, Stanford, and Cambridge, is on a mission to develop specialized, efficient AI.
- Fastino's GLiNER family of open source models has been downloaded more than 50 million times and is used by companies such as NVIDIA, Meta, and Airbnb
- Fastino has raised $25M (as featured in TechCrunch) through our seed round and is backed by leading investors including Microsoft, Khosla Ventures, Insight Partners, GitHub CEO Thomas Dohmke, Docker CEO Scott Johnston, and others.

What You’ll Work On:

- Help define the technical direction for Fastino’s platform, contributing to the architecture decisions that let us scale without slowing down.
- Design and build our agent harness, including the runtime loop, tool calling, context management, and error recovery, plus the eval harnesses that measure agent reliability.
- Build and scale our AI training and inference pipelines, pushing on latency, throughput, and cost as usage grows.
- Own deployment of the Fastino platform into customer-managed AWS VPCs using Kubernetes and Terraform, including install, upgrade, and observability paths that work in environments we don’t control.
- Build secure sandboxed execution environments for agentic workloads on Modal Sandboxes.
- Ship full-stack features end-to-end while owning the hardest, most ambiguous problems on the team.
- Partner closely with AI researchers to take new models from research to production, including deployment, evaluation, and monitoring.
- Raise the engineering bar through code reviews, mentorship, and setting practices the rest of the team builds on, including how we work with AI coding agents.
- Talk to customers and turn their feedback into product decisions, fast.

What We’re Looking For:

- Required: 8+ years of hands-on software engineering experience, including time as a tech lead or driving architecture across a team or product.
- Required: Strong architectural skills, with a track record of designing and scaling production systems that handle real load.
- Required: Production experience with agentic systems, AI training pipelines, or inference pipelines, ideally more than one.
- Required: Hands-on experience deploying software on AWS with Kubernetes and Terraform, ideally into customer-managed or multi-tenant environments.
- Required: Experience building and running sandboxed execution environments for agent workloads, ideally with Modal Sandboxes.
- Required: Extensive experience building with AI coding agents, and a demonstrated ability to guide them to produce clean, production-quality code. You know how to scope tasks, review output critically, and catch what agents get wrong.
- Required: You thrive in ambiguity, make good calls without a playbook, and know when to move fast versus when to build for the long term.
- Optional: Experience building agent harnesses or frameworks used in production, including familiarity with MCP or similar tool protocols.
- Optional: Experience with LangSmith or similar tooling for tracing, evaluating, and monitoring agents.
- Optional: Hands-on experience with inference optimization, like batching, quantization, GPU utilization, or serving frameworks such as vLLM, SGLang, or Triton.
- Optional: Deep experience with high-concurrency backend systems or low-latency API design.
- Optional: Startup experience, ideally as an early engineer helping a team grow.

## About fastino.ai

## Company Overview
- **One-liner**: Fastino is an applied research lab that develops specialized small language models and a fine-tuning platform (Pioneer) for enterprise AI workflows.
- **Entity Type**: Private (Seed stage; $24.5M total funding)
- **Headquarters**: Palo Alto, California, United States
- **Founded**: 2024
- **Founders**: Ash Lewis (CEO) and George Hurn-Maloney (COO)

## Core Business
- **Primary industry**: Artificial intelligence / Research Services
- **Target customers**: B2B – engineering teams at enterprises needing task-specific AI models (e.g., PII redaction, entity extraction, classification, summarization)
- **Mission or purpose**: “Building the future of small language models” – advancing specialized, efficient AI that can be trained and deployed on commodity hardware.

## Products & Services
- **[GLiNER / GLiNER2](https://fastino.ai/)**: Open-source, open-vocabulary entity extraction models. Used in production systems serving over 1 billion daily end users.
- **[GLiGuard](https://fastino.ai/)**: Lightweight guardrail model for prompt injection, jailbreak attempts, and unsafe content classification.
- **[Pioneer](https://fastino.ai/)**: “The first model agent” that automatically retrains baseline open-source small language models on live inference data, improving accuracy over time. Provides fine-tuning, deployment, and adaptive inference without writing code.
- **Task-Specific Language Models (TLMs)**: Proprietary small models focused on narrow enterprise tasks such as PII redaction, text-to-JSON extraction, function calling, and text classification.

## Market Standing
- **Valuation/Market Cap**: Not disclosed (private)
- **Key Metric**: Total Funding – $24.5M
  - Pre-Seed (Nov 2024): $7.0M led by Insight Partners and M12 (Microsoft’s Venture Fund)
  - Seed (May 2025): $17.5M led by Khosla Ventures; also includes investment from Dropbox Ventures (Aug 2025)
- **Notable Investors/Partners**: Khosla Ventures, M12, Insight Partners, Dropbox Ventures
- **Growth Signals**:
  - 19 employees (+28.6% YoY) [linkedin.com](https://www.linkedin.com/company/fastinoai)
  - Open-source models with 3M+ monthly downloads, 3,200+ GitHub stars, and 1.1B+ end users [fastino.ai](https://fastino.ai/)
  - Launched Pioneer (agentic fine-tuning platform) in April 2026 [aventure.vc](https://aventure.vc/companies/fastino-palo-alto-ca-us)
  - Attracting talent from Google DeepMind, Microsoft, and other top AI labs [linkedin.com](https://www.linkedin.com/company/fastinoai)

## Competitive Advantages
- **Architecture efficiency**: Models are small enough to be trained on low-end gaming GPUs (total hardware cost <$100k) yet outperform much larger general-purpose LLMs on specific tasks [techcrunch.com](https://techcrunch.com/2025/05/07/fastino-trains-ai-models-on-cheap-gaming-gpus-and-just-raised-17-5m-led-by-khosla/).
- **Single-token inference**: Small size allows entire responses to be delivered in milliseconds, enabling real-time use cases.
- **Continuous improvement via Pioneer**: The platform retrains deployed models on live production traces, creating a feedback loop that improves accuracy over time – a differentiator from static model offerings.
- **Open-source foundation**: GLiNER and GLiNER2 have built a strong developer community and adoption.

## Strategic Focus
- **Hiring contrarian researchers**: The company is deliberately recruiting AI researchers who “maybe have a contrarian thought process to how language models are being built right now” – i.e., those not obsessed with scaling to trillion parameters [techcrunch.com](https://techcrunch.com/2025/05/07/fastino-trains-ai-models-on-cheap-gaming-gpus-and-just-raised-17-5m-led-by-khosla/).
- **Expanding Pioneer ecosystem**: Making fine-tuning and adaptive inference accessible to any developer without coding, targeting broader enterprise adoption.
- **Deepening enterprise sales**: Open positions for Founding Head of Sales and Sales Engineer indicate a push to scale commercial adoption.

## Why Work Here
- **Small, focused team** (~15–19 employees) with high ownership and impact – typical for an early-stage startup.
- **Cutting-edge research culture**: Engineers and researchers work on novel model architectures, agentic fine-tuning, and efficient AI – not just scaling up existing LLMs.
- **Remote-friendly**: Presence in the US (Palo Alto), UK, Germany, and Réunion suggests a distributed team; specific remote/hybrid policy not detailed but likely flexible for the right talent.
- **Open source contribution**: Engineers can contribute to widely-used projects (GLiNER, GLiNER2) and see their work used by millions.
- **Active job openings** (as of mid-2026): Software Engineer (LLMs), AI Engineer, Sales Engineer, Founding Head of Sales – roles offer opportunity to shape the company’s technical and commercial direction [jobs.ashbyhq.com](https://jobs.ashbyhq.com/fastino-ai).

## Sources
1. [fastino.ai](https://fastino.ai/) – Official website (products, mission, metrics)
2. [linkedin.com](https://www.linkedin.com/company/fastinoai) – LinkedIn company page (headcount, funding, team, locations)
3. [techcrunch.com](https://techcrunch.com/2025/05/07/fastino-trains-ai-models-on-cheap-gaming-gpus-and-just-raised-17-5m-led-by-khosla/) – TechCrunch article on seed funding and model architecture
4. [aventure.vc](https://aventure.vc/companies/fastino-palo-alto-ca-us) – aVenture company research (founding date, funding history, Pioneer launch)
5. [jobs.ashbyhq.com](https://jobs.ashbyhq.com/fastino-ai) – Official careers page (open positions)

## Other roles at fastino.ai

- [Forward Deployed Engineer](https://feeny.ai/job/forward-deployed-engineer-fastino-ai-san-francisco-hhz95e0tx414) — San Francisco, CA
- [Distinguished Agent Engineer](https://feeny.ai/job/distinguished-agent-engineer-fastino-ai-san-francisco-n75e1rst2zfc) — San Francisco, CA
- [Account Executive](https://feeny.ai/job/account-executive-fastino-ai-san-francisco-ecvgcvs61w7y) — San Francisco, CA