Hindsight vs Letta
A side-by-side comparison of Hindsight and Letta, two Memory tools, drawn from Ignaite's continuously-verified listings.
Compared from listings verified as of
At a glance
| Attribute | Hindsight | Letta |
|---|---|---|
| Category | Memory | Memory |
| Pricing | FREEMIUM | FREEMIUM |
| License | Open core | Open core |
| Deployment | Hybrid | Hybrid |
| Platforms (differs) | API | API, CLI, macOS, Windows, Linux |
| Model support | BYO key / model | BYO key / model |
| Vendor (differs) | Vectorize | Letta |
| Capabilities (differs) |
|
|
The honest brief
Hindsight
Goes beyond storing facts: agents reflect on past runs to update beliefs and avoid repeating mistakes, topping LongMemEval for long-horizon recall.
- Reflection: agents learn from experience
- Top LongMemEval accuracy (91.4%)
- MIT-licensed, self-hostable
- Human-like memory networks
- Managed Hindsight Cloud option
- New (2026), small ecosystem so far
- Tied to Vectorize's stack and roadmap
- Reflection adds LLM cost and latency
Letta
The productized MemGPT successor — agents edit their own memory blocks (memory-as-OS) to manage a finite context window.
- Self-editing agent memory
- Open source, model-agnostic
- REST APIs + multi-language SDKs
- Reference architecture for memory
- Developer-focused, not no-code
- Memory model has a learning curve
- Younger, evolving framework
When to pick which
Across the signals we compare, Hindsight and Letta differ on platforms:
- Platforms
- API · API, CLI, macOS, Windows, Linux
Their capability lists differ in recorded depth — compare the full lists above before deciding.