Update first.
Open the London5 menu and choose Check for Updates…. The alpha moves quickly, and most fixes reach you this way before they reach this page.
London5 Support
Help for the London5 app.
London5 runs on your own Mac and sends nothing home — no telemetry, no automatic crash reports. So support starts with you telling us what happened, and this page is how to do that well: what to check first, where the app keeps its logs, and how to reach a person.
Support is by email, at contact@london5.com. A person on the team answers — during the alpha, the people building it.
Before you write
Three checks that settle most of it.
Quit and reopen.
Quitting London5 stops the engine and the Python bridge with it; reopening starts both clean. The three lights in the top bar — ENGINE · AI · TOOLS — tell you what came back and what did not.
Look at the log.
London5 → Show Logs in Finder (⇧⌘L) opens the app's logs. If something failed to start, engine-supervisor.log says why in its last lines — that file is usually the whole answer.
London5 needs macOS 14 Sonoma or later. Apple Silicon is recommended; Intel Macs are supported. The Try it free page has the full requirements.
Where things are
Four folders. Nothing anywhere else.
Every path below is on your Mac and only there. Two are logs, one is your data, one is the models — and knowing which is which is most of what a support conversation needs.
- ~/Library/Logs/London5/
- the app — london5-macos.log, engine-supervisor.log, london-py-supervisor.log
- ~/Library/Logs/london5/
- the engine and your venues — london5.log, kraken.log, alpaca.log, finnhub.log
- ~/Library/Application Support/london5/
- your data — accounts, trades, chats, research, settings, in local databases. Back this one up.
- ~/Library/Application Support/London5/models/
- the local models. Only downloads — nothing of yours lives here.
Writing to us
What to put in the message.
Five things. With them, the first reply is usually the answer; without them, the first reply is a request for them.
- Which build
- London5 → About London5 shows the version and build number.
- Which Mac
- The macOS version, and whether it is Apple Silicon or Intel.
- What happened
- What you did, what you expected, what you saw — in that order. A screenshot of the top bar helps.
- The log
- Attach the relevant file from Show Logs in Finder, or paste its last lines. Logs stay on your Mac until you send them, so read one before you do: it carries the symbols you trade — attach it to your email, or paste only its last lines.
- Never your keys
- Broker and exchange keys live in your keychain. We never ask for them, and no fix needs them.
Common questions
The things that come up.
The engine light stays red and nothing loads.
Quit London5 and reopen it. If the light stays red, open Show Logs in Finder and read the last lines of engine-supervisor.log — the engine writes the reason it could not start. Send those lines to contact@london5.com.
Where is my data, and how do I back it up?
Everything London5 knows — accounts, trades, chats, research, settings — is in local databases under ~/Library/Application Support/london5. Copy that folder with London5 closed and you have a complete backup. The models under …/London5/models are only downloads.
I installed London5 on another Mac and it asks me to enrol it.
Each Mac is an installation on your account. Enrol with the same email, confirm the message london5.com sends you, and the Mac appears under Account → Installations. To carry your history across, copy the data folder above with London5 closed on both machines.
Does support need access to my machine, or my keys?
No. There is no remote access and we never ask for a key. We work from what you send — the description and the log — and reply with what to do.
Something is wrong with my subscription or invoice.
Account → Subscription & Billing opens your billing portal. If it will not open, or a subscription that was granted directly looks wrong, write to the team at contact@london5.com and say which email the account is under — never the card.
Does London5’s AI trade real money?
No. London5’s AI researches and simulates; it does not place live orders or manage your money. Simulations use paper capital and do not unlock live trading. You decide and trade at your own broker. See the scope and disclosures for the current offering.