Magnitude Relay: The Fastest Nostr Relay

Relays are the servers that carry Vector's encrypted messages between devices. They can't read your DMs or Communities (everything is gift-wrapped), but they decide how fast those load, sync and arrive.

Vector's relays ran strfry, the workhorse of Nostr. It served us well, but it's built for every kind of Nostr traffic, and Vector's is specific: gift-wrapped DMs, Concord Communities, negentropy sync and live typing indicators. So we built a relay for exactly that: Magnitude Relay, sibling to Magnitude, our media server. It took over both of Vector's relays on 21–22 October. Nobody had to update a thing.

DMs and Communities Load up to 10× Faster

Same machine, same two CPU cores, the same million Vector-shaped events, every answer checked. Here's how long each relay takes to answer what Vector asks.

The last row counts most. We replayed 951 requests built from jskitty.com's 4.9 million real events against both relays side by side. The answers matched, except for messages their senders or recipients had asked to delete, which strfry was still serving. Magnitude Relay averaged 0.45 ms; strfry, 17.4 ms.

Sync up to 6.7× Faster

After time offline, Vector catches up with negentropy (NIP-77): the app and relay compare compact fingerprints, and only what's missing is sent. Magnitude Relay builds those fingerprints from its index alone, without opening a single message.

The relays sync each other the same way, so a message sent to jskitty.com in Helsinki reaches Vector Asia in Kuala Lumpur in under a second.

Community Messages Arrive 72× Sooner

When someone posts in a Community, the relay stores the message and pushes it to every member online. That gap is the relay's whole share of how instant chat feels.

strfry picks up new messages for delivery in small batches, which adds tens of milliseconds to each one. Magnitude Relay delivers the moment a message is safely on disk.

Ready to Scale

Today each Vector relay averages about 34 requests and 3 new messages a second. On just two CPU cores, Magnitude Relay handles over 11,000 DM inbox loads and 29,000 new messages a second: more than 300× today's reads and 9,000× today's writes.

Every message reaches each relay more than once (Vector sends to several, and the relays sync each other), so skipping duplicates 24× faster frees the relay for real work.

Proven in Production

Vector's two relays, in the 30 hours after their latest update on 22–23 October:

A switch with zero downtime

No downtime, a way back at every step, no message lost.

• 20–21 OctDress rehearsal. A hidden copy of Magnitude Relay, fed every new event live, answers real requests side by side with strfry, and catches two bugs before any user could.
• 21 Oct · 21:56 UTCjskitty.com switches. 4,877,620 events copied over, one web server reload, strfry kept in sync behind it as a way back. Nobody is cut off.
• 22 Oct · 01:44 UTCVector Asia switches. The two relays now sync each other directly, typing indicators included.
• 22 Oct · middaystrfry retires on both servers after a quiet night.

Updates roll out one relay at a time, each back online in about half a second. A release that isn't healthy within 30 seconds is rolled back automatically.

Built for Self-Hosters

Our rule: maximum speed on minimum hardware. Every change that cost resources had to prove it made the relay faster.

Most relays, strfry included, slow down once the database outgrows memory; this summer, that happened to jskitty.com. So we tested Magnitude Relay with 13 GB of real data and only 1 GB of memory:

In production each relay uses 190–370 MB of its own memory while serving over a thousand connections. After loading a million events, its total footprint was 1.2 GB against strfry's 3.1 GB, 61% less (most of both is cached database the system can reclaim).

• One program, one settings file. magnitude-relay init writes a commented one.
• Moves in from strfry. Imports strfry exports directly, checking every signature, and can sync with a running strfry while you try it.
• HTTPS built in. Fetches and renews its own certificates, or sits behind nginx on a local socket.
• Live backups. A consistent copy of the store without stopping the relay.
• Dashboard and metrics. The page above, plus Prometheus metrics.
• Relay-to-relay sync. Keep several relays complete with NIP-77, as jskitty.com and Vector Asia do.

Magnitude Relay is open source under the AGPL-3.0: run your own from github.com/VectorPrivacy/magnitude-relay.

Private by Design

A relay can't read gift-wrapped messages, but it decides what's kept, and whether delete means delete.

Moving jskitty.com over, we found 38 vanish requests and 24 deletions strfry had never applied, covering over a thousand events. Magnitude Relay applied them all on import, and now overwrites deleted data on disk. Both relays also serve Tor and I2P, as gateways to the relay only.

Standing on the Shoulders of Giants

• strfry and Doug Hoyte, for carrying Vector's messages from the start, and for negentropy, the sync protocol both relays still speak
• The Nostr community, for an open protocol anyone can build a relay for
• Rust and Tokio, for making fast and safe the same thing

Like Open-Source DOOM, Magnitude Relay was built as a collaboration between a human developer and an AI (Claude, by Anthropic).