WireMock vs Gretel.ai

Free tier available

Quote on request

Open source is free; WireMock Cloud is a paid hosted service for shared team mocks.

The old credit-based self-serve tier is gone. The successor microservices are licensed through NVIDIA AI Enterprise; NeMo Data Designer can be tried on build.nvidia.com.

Open-source WireMock is complete and free.

Category standard

WireMock Inc. · since 2013

Emerging

NVIDIA (formerly Gretel) · since 2019

• Fault and latency injection lets you test the error paths that never occur on demand in a real sandbox.
• Record-and-replay produces a realistic mock from live traffic quickly.
• Runs anywhere: embedded, standalone, container or cloud.

• Formal differential-privacy guarantees rather than best-effort masking, now via DP-SGD in NeMo Safe Synthesizer.
• Synthetic data preserves statistical relationships useful for analytics and model training.
• Backed by NVIDIA's platform investment rather than a single startup's runway.

• Recorded stubs drift from the real service unless you re-record or verify contracts.
• Complex stateful scenarios get verbose in JSON.
• HTTP only — not for message queues or gRPC without extensions.

• No longer buyable as Gretel — you are procuring NVIDIA AI Enterprise, which is far heavier than the old self-serve signup.
• Model training adds time and cost compared to rule-based masking.
• Safe Synthesizer trains on a real dataset, so it does not help with greenfield data that does not exist yet.

Teams whose integration tests depend on third-party HTTP services.

Regulated enterprises already standardising on NVIDIA AI Enterprise. Teams that wanted Gretel's self-serve tier should look at Tonic or Neosync instead.