If your goal is realistic, multi-turn customer-service conversations—rather than generic tabular synthetic data—I’d shortlist these:
| Tool | Best for | My take |
|---|
| NVIDIA NeMo Data Designer | Programmable, large-scale conversation datasets | Best overall for technical teams |
| SDialog | Persona-driven customer dialogue generation | Best if conversation realism is the priority |
| NVIDIA NeMo Safe Synthesizer | Generating synthetic data from existing customer data | Best when you have real conversations to learn from |
| Custom LLM pipeline | Maximum control over scenarios/personas/evaluations | Best if you have engineering resources |
My recommendation: NeMo Data Designer
build.nvidia.com is particularly compelling because it is designed as a compound AI system for synthetic data generation, and NVIDIA provides workflows for generating training-ready SFT chat data. Its synthetic-data tooling supports domain-specific topics, scenarios and personas, and can produce structured conversation datasets.
For customer conversations, I'd structure generation around:
- Customer personas: frustrated customer, confused novice, loyal customer, price-sensitive buyer, technical expert, etc.
- Intent/scenario: refund, cancellation, billing dispute, delayed order, account access, product defect, upgrade, outage.
- Conversation dynamics: interruptions, ambiguity, changing requirements, incomplete information, repeated questions, escalation.
- Agent behavior: policy adherence, tool calls, authentication, clarification, empathy, escalation.
- Difficulty tiers: straightforward → ambiguous → adversarial/edge case.
- Evaluation labels: resolution status, policy compliance, customer sentiment, escalation reason, intent, tool-call correctness.
NeMo already has customer-service evaluation scenarios covering things such as billing disputes, refunds, defective products, order delays, outages, account access and plan upgrades, which is a useful indication of the kinds of scenarios you can model.
If you already have real customer conversations
I'd look harder at NeMo Safe Synthesizer. It can take existing CSV/JSON/JSONL/Parquet/text data, perform PII replacement, fine-tune a model, generate synthetic records, and produce quality/privacy evaluation reports.
That's a fundamentally different approach from simply prompting an LLM:
Real conversations → remove/replace PII → learn distribution → generate new conversations → evaluate similarity + privacy
That generally has a better chance of capturing your company's actual conversational style and weird edge cases.
One important distinction
If you're building this dataset for training/evaluating a customer-service LLM, I would not choose a generic synthetic-data product such as Faker, Mockaroo, or a tabular synthetic-data platform. Those are useful for structured records, but your hard problem is generating coherent multi-turn behavior.
For example, a good generator should be able to produce something like:
Customer starts by asking why their bill increased → agent explains → customer reveals they were promised a different price → agent asks for account details → customer changes the subject to cancellation → agent discovers cancellation fee → customer becomes frustrated → agent offers an alternative → customer accepts.
That stateful progression is much more valuable than simply generating 10,000 independent {customer_message, agent_response} pairs.
What I'd use
If I were building this today:
No existing data:
→ NeMo Data Designer + an LLM judge/evaluator
Have thousands of historical conversations:
→ NeMo Safe Synthesizer + evaluation pipeline
Need maximum realism/control:
→ Build a multi-agent simulator where separate models play customer, agent, and optionally tool/backend, with deterministic scenario state underneath.
For model training, I'd ultimately output something like OpenAI-style messages JSONL; NVIDIA's tooling supports multi-turn chat datasets in this format.
If you tell me what the conversations are for (fine-tuning, evals, chatbot testing, QA, etc.) and roughly how many you need (10K / 100K / 1M+), I can recommend the specific tool/architecture and give you a concrete generation pipeline.