---
title: "mem0 alternative for temporal memory"
description: "past.dev is a mem0 alternative for temporal storage. Compare evidence, deployment, changed-fact handling, and tests for evaluating either system."
canonical: https://past.dev/mem0-alternative
last-updated: 2026-08-31
---
# mem0 alternative for changing facts

Source: https://past.dev/mem0-alternative

Teams evaluating mem0 alternatives often compare hosted pricing, model calls during ingestion and support for changing facts. past.dev stores facts with validity windows and supersession records. Recall returns dated evidence and an explicit status, including `NoKnownSupport` when the stored evidence cannot answer the question.

## When to use mem0

[mem0](https://github.com/mem0ai/mem0) is available under Apache 2.0 and provides Python and TypeScript SDKs. It extracts user memories from conversations and supports per-user personalization in conversational applications. It can run as a library, a self-hosted service or a managed service. See [past.dev vs mem0](/vs/mem0) for the detailed comparison.

## Why teams go looking for an alternative

- **Ingestion cost.** mem0 uses a language model to extract memories during writes, as described in its [documentation](https://github.com/mem0ai/mem0). Estimate this cost at your expected write volume.
- **Hosted tiers.** Feature availability varies by hosted tier. Check the current [pricing](https://mem0.ai/pricing) against your deployment requirements.
- **Changed facts.** Recency can affect ranking. Evaluate whether stored facts include validity periods and whether previous values remain available for point-in-time queries.

## What to test in any alternative

1. State a fact, change it, ask for the current value. Then ask what it was before the change. Both answers should exist, with dates.
2. Backfill a year of records with their original timestamps and ask a date question. The stored event dates must match the source timestamps rather than the import date.
3. Refer to the same person three ways, email signature, transcript name, chat handle, and ask a question that requires joining them.
4. Ask something the data cannot answer. The response should report insufficient evidence.
5. Price the memory layer itself at your write and read volume, including any model calls inside it.

Our [benchmark methodology](/benchmarks/methodology) describes these tests in more detail.

## How past.dev answers them

past.dev is a memory API with four endpoints. `POST /api/v1/ingest` accepts raw text with its original timestamp. Extraction, entity resolution and storage on a [temporal knowledge graph](/glossary/temporal-knowledge-graph) run on the service. A changed fact closes the previous fact's [validity window](/glossary/validity-window). `POST /api/v1/recall` returns ranked, dated evidence with `Supported`, `Conflicted` or `NoKnownSupport`. The [benchmarks page](/benchmarks) documents recall evaluation.

## When to use each product

- **Use mem0** for self-hosted, per-user conversational memory based on extracted preferences and profile facts.
- **Use past.dev** for changing operational facts, team knowledge, dated evidence and explicit insufficient-evidence status.

The [quickstart](/docs/memory-api/quickstart) shows the four API calls. A migration requires re-ingesting source history with original timestamps. [What is agent memory?](/what-is-agent-memory) describes the main architecture options.

## Frequently asked questions

### Is past.dev open source like mem0?

The API uses plain HTTP and requires no SDK. Managed and self-hosted deployments are available by contact. If you require an open-source engine, evaluate Zep's Graphiti and cognee. Our comparison pages cover both.

### Can I keep mem0 for personalization and add past.dev for facts?

Yes, and some teams do: extracted preferences in mem0, temporal facts and team knowledge in past.dev. The division follows the data: current-state personal preferences versus changing, dated, shared facts.

## Related

- [past.dev vs mem0, in detail](https://past.dev/vs/mem0)
- [past.dev and OpenMemory](https://past.dev/compare/openmemory)
- [Zep alternative](https://past.dev/zep-alternative)
- [How to benchmark agent memory](https://past.dev/benchmarks/methodology)
- [Quickstart](https://past.dev/docs/memory-api/quickstart)