One event store for system history and AI memory.
AllSource Event Store records decisions and state changes as immutable events. Core keeps durable history; Query Service separates HTTP, realtime, analytics, and projection reads; Prime gives agents cross-session memory backed by source events.
Hosted plans from £18.99/month after trial · Apache-2.0 Core available to self-host
What did the user do yesterday at 3pm?
recalling from event log…
What breaks without an event history
Agent context disappears
Conversation context ends with a session. Without durable storage, an agent cannot recover prior decisions, evidence, or state after a restart.
Current state hides why
A row shows what is true now, not which changes produced it. Debugging and audit work then depend on scattered logs and application-specific fixes.
Historical queries become projects
Reconstructing state at a past timestamp usually means joining logs, snapshots, and database records. An ordered event history makes that query explicit.
From event write to durable context
One ordered history supports application state, operational analysis, and agent memory.
- 01
Write events
Send structured events through HTTP, WebSocket, an SDK, or MCP. AllSource appends accepted writes to an immutable stream.
- 02
Build useful views
Query Service folds ordered Core events into tenant-scoped current-state projections and separates HTTP, realtime, and analytics reads.
- 03
Query and replay history
Serve request-response queries, push live channel updates, run analytics, or rebuild a read model from the same source history.
What you can do with stored history
Each capability uses the same append-only event model, whether AllSource runs hosted or on your infrastructure.
Event Timeline
Read an entity's complete history in order, inspect each payload, and trace which event caused a state change.
Open demo →Time travel
Ask what a stream contained at a sequence or timestamp and reconstruct the matching state.
Open demo →Graph visualisation
Explore Prime nodes and relationships with source-event provenance instead of an opaque knowledge graph.
Open demo →Stream pipelines
Filter, map, reduce, window, or branch accepted events inline while preserving source history.
Open demo →Rebuildable projections
Fold existing events into tenant-scoped read models for HTTP, realtime, and analytics consumers.
Open demo →MCP access for agents
Let MCP clients query timelines, reconstruct state, and inspect events through explicit tenant-scoped tools.
Open demo →Claims you can inspect
Numbers link back to reproducible commands and source code. Architecture pages explain which service owns each part of the data path.
11.9μs
Core indexed-read p99
Published in-memory reference benchmark
469K
events/sec
Published batch-ingestion benchmark
WAL + Parquet
durable storage
Write-ahead log with columnar persistence
Apache-2.0
core licence
Inspect, run, and modify the event-store core
Pricing
Indie
£18.99
Includes 50K x402 calls. $0.0001/call after.
- 500K events/month
- 14-day retention
- 3 streams
- Hosted MCP: read
- Email support (48h)
Studio
£78.99
Includes 500K x402 calls. $0.0001/call after.
- 5M events/month
- 90-day retention
- Unlimited streams
- Hosted MCP: read + write
- Email support (24h) + Discord
Scale
£298.99
Includes 5M x402 calls. $0.0001/call after.
- 50M events/month
- 365-day retention
- Unlimited streams
- Hosted MCP: read + write + dedicated
- Priority support + Slack
Enterprise
Regulated / SLA workloads. Dedicated MCP cluster. Negotiated volume, unlimited retention, 24/7 + dedicated SE.
FAQ
Recent product and engineering notes
AllSource Core, Query Service, Prime, Hosted, and MCP Explained
Core stores events. Query Service separates reads. Prime derives agent memory. Hosted AllSource operates services. MCP connectors expose tools.
What Is AllSource Event Store?
AllSource Event Store is developer infrastructure for durable application history and AI-agent memory. This answer separates it from ArcGIS AllSource and explains Core, Query Service, Prime, hosted services, and MCP.
AllSource vs stoolap: An Embedded SQL Database Meets an Event Store
stoolap is an embedded relational SQL database in pure Rust; AllSource is an immutable event store and agent-memory service. They overlap on AI features but solve different problems. The honest, reproducible comparison — including a benchmark you can run yourself.
Write → inspect → query
Store one real event, then query it back.
Start with hosted AllSource, or run the Apache-2.0 core on your own infrastructure. Both use the same event model and APIs.