ML Engineer (LLM)

Synthflow AI is a no-code platform for deploying voice AI agents that automate phone calls across contact center operations and business process outsourcing (BPO) at scale. We help mid-market and enterprise companies manage routine calls to save teams time and resources.

Our agents have already delivered measurable impact:

• Over 5 million hours of contact center operations saved

• 35% more calls answered compared to non-AI operators

• 45 million calls handled with a 99.9% uptime

Backed by Accel, Atlantic Labs, and Singular and trusted by over 1,000 customers, our growth leads an industry shift toward sophisticated and accessible conversational AI.

The Role

We are looking for a hands‑on ML Engineer who lives at the intersection of TTS, STT and large language models. You will design and ship new low‑latency voice capabilities, working closely with product, research and infrastructure teams to push the boundaries of natural, multilingual conversation.

What You’ll Do

• Architect & implement real‑time speech pipelines (ASR → LLM → TTS) that meet stringent latency and quality targets.

• Evaluate and fine‑tune state‑of‑the‑art ASR, LLM and TTS models—both commercial and open‑source—and integrate the best performers into production.

• Optimise inference through quantisation, distillation, hardware‑aware graph compilation and reinforcement‑learning‑based tuning.

• Expose scalable APIs & micro‑services with Python/FastAPI, gRPC or WebSocket streaming, backed by robust observability and autoscaling.

• Own deployment across cloud and on‑prem environments, collaborating on containerisation (Docker), orchestration (Kubernetes) and CI/CD workflows.

• Stay ahead of the curve by tracking research, running experiments and sharing learnings with the broader team.

What we’re looking for

• Python Engineering: 5+ years writing production‑grade, well‑tested Python; deep familiarity with async, typing and performance profiling

• Speech / Audio: Hands‑on experience building real‑time ASR, TTS, voice chat or streaming audio products

• LLM Tooling: Fine‑tuning, prompt design, evaluation, retrieval‑augmented generation; familiarity with frameworks such as Openpipe/ART, LangChain, LlamaIndex or similar

• Systems & MLOps: Containerisation, GPU scheduling, observability, DevOps on GCP or AWS; infrastructure‑as‑code principles

• API Design: Building and maintaining high‑throughput REST/gRPC/FastAPI services; securing and monitoring them in production

Bonus Points

• Model compression expertise (quantisation, pruning, ONNX/TensorRT)

• Knowledge of audio and acoustics

• Experience with reinforcement‑learning‑from‑human‑feedback (RLHF) or direct preference optimisation

• Contributions to open‑source ML/speech projects (share your GitHub!)

• Familiarity with GPU inference servers (Triton, KServe) or distributed compute frameworks (Ray)

Founded in Berlin in 2023 by serial entrepreneurs Albert Astabatsyan, Hakob Astabatsyan, and Sassun Mirzakhan-Saky, Synthflow AI democratizes access to advanced voice AI with a no-code platform that lets enterprises easily create, deploy and scale natural-sounding, cost-effective voice agents tailored to their business needs.