Polius2007

I build software for crypto traders: XTester Studio for strategy research and backtesting, and CopyTrader for traders who want to offer trade copying to their own audience.

Here I'll share what I'm working on, the experiments behind it and the product decisions along the way. That includes how to test a strategy idea, what a backtest can tell you, and the practical work of building a copy-trading service.

If you research strategies or run a trading community, I'd like to hear what takes the most time in your workflow.

My projects: https://easytrading.pw

#Backtesting #CopyTrading

A tiny test deposit to Kraken can be too small to credit, and sending the main transfer afterward won't rescue it.

Kraken's existing deposit rules say a crypto deposit below the required minimum is marked “Failed” and permanently lost. A later deposit that meets the minimum does not get the first one credited. Two transfers aren't added together to clear that threshold.

The amount also has to meet the minimum after network fees are deducted. A test sized exactly at the minimum can therefore fall short if the sending service deducts its network fee from that amount.

Before choosing the test amount, open the relevant deposit page in your Kraken account. Kraken says its published minimums can change without notice and directs users there for current values. Size the test by what will arrive, not just what leaves the sending account.

Source: https://support.kraken.com/articles/360000292886-cryptocurrency-deposit-fees-and-minimums

Crypto.com's Ruby, Jade and Indigo cards for European residents no longer offer unrestricted fee-free foreign-currency spending. The change took effect on October 1.

For non-EUR purchases and ATM transactions outside the EU and UK, Ruby now has a €400 fee-free allowance per calendar month. Jade and Indigo have €800. Above those amounts, the foreign transaction fee is 2%.

Within the EU and UK, the listed fee is 0.2% from the first non-EUR transaction. Those €400 and €800 allowances belong to the outside-EU-and-UK category; they aren't a general foreign-currency allowance.

If you chose one of these cards for spending abroad, check October's transactions against the new schedule rather than last month's terms. The previous schedule explicitly listed no foreign transaction fee for these tiers. ATM withdrawals also have a separate monthly free limit, with a 2% withdrawal fee above it.

Source: https://help.crypto.com/en/articles/5977463-crypto-com-prepaid-visa-card-fees-and-limits-europe-for-users-with-a-residential-address-in-europe

Warming up a space telescope can clear ice from its mirrors and create another problem: the structure expands, disturbing the alignment needed to measure distant galaxies.

That trade-off shaped a repair to ESA's Euclid telescope in March 2024. A thin layer of ice was reducing the light reaching its visible-light instrument. The water had come from Earth, absorbed during assembly and slowly released by spacecraft materials into the vacuum. Some of it settled on the cold optics.

Heating the whole spacecraft was an available option. But ESA said the structure might not return to precisely the same state after cooling, leaving several weeks of fine recalibration before the telescope could recover its required precision.

The team instead planned to warm selected mirrors separately and measure how much light came back after each step. That made the repair a way to locate the contamination, while limiting how much of the telescope had to change temperature.

ESA's March 26 report describes heating the main suspect, a cold mirror behind the telescope's main optics, from -147°C to -113°C. Still far below freezing on Earth, but warm enough in a vacuum to remove the ice. The team reported receiving 15% more light almost immediately.

The early success meant they could identify where the ice had collected and target that area again. Water was expected to keep escaping from the spacecraft's materials, so this was maintenance Euclid would need repeatedly. A selective warm-up offered a way to restore its view without routinely heating the entire structure and paying the recalibration cost.

Sources:
https://www.esa.int/Science_Exploration/Space_Science/Euclid/Euclid_s_sight_restored
https://www.esa.int/Science_Exploration/Space_Science/Euclid/Operations_begin_to_de-ice_Euclid_s_vision

Image: AI-generated editorial still life of an optical mirror, not Euclid hardware or a photograph of the repair.

You return to a research notebook, ask the same question, and get a different answer. The documents behind it may have changed while you were away.

In Google's existing Gemini Notebook workflow on desktop, imported Drive files can stay connected to their originals. A colleague's edits can reach the notebook without another upload: Google says changes sync every few minutes and update when you open it.

A shared source can also disappear from the conversation. If its owner deletes the file or removes your access, Google says notebook chats stop referencing it.

For a project that keeps evolving, that connection is useful. For comparing yesterday's analysis with today's, the notebook name alone doesn't identify the evidence you used. Check the linked documents' revisions and availability before treating the changed answer as the AI changing its mind.

Source: https://support.google.com/gemininotebook/answer/16215270?co=GENIE.Platform%3DDesktop&hl=en

A photo from my desk as we work towards the next XTester Studio releases.

The tester can now execute strategies in the cloud and through the launcher, and work with portfolios of strategies. These capabilities are coming together as we prepare several releases.

Portfolio support is a part I’m particularly interested in: moving beyond testing one strategy at a time to working with several together.

Still plenty to finish, but the platform is moving forward. I’ll share more as the releases are ready.

Blockstream reopened multisig account creation in its app on October 13. For Bitcoin holders choosing between the two account types, the important difference is how they recover funds without two-factor authentication (2FA).

In a 2-of-2 account, normal spending uses your device key and Blockstream's server key. Each deposit has its own timelock. Once that expires, those coins can be spent with your key alone. The default is roughly a year, so losing access to 2FA can leave a wait before that recovery route opens. The app prompts users to redeposit coins to renew their 2FA protection.

A 2-of-3 account adds a second recovery phrase for you to keep offline. Combined with your device key, it lets you recover without waiting for a timelock. Everyday sends still use the device-and-server arrangement. This option is Bitcoin-only, not available for Liquid.

The choice is an extra backup to safeguard versus a possible recovery wait. Blockstream's recovery tool is separate software; building that recovery functionality into the app is still on its roadmap. Existing legacy multisig accounts don't need to migrate.

Sources:
https://blog.blockstream.com/multisig-is-back-in-the-blockstream-app/
https://help.blockstream.com/blockstream-app/manage-2fa-accounts/2fa-multisig-protection-explained

Kraken reported a chart-data problem on October 13, 2026: some Futures requests could return historical candles instead of current data, across all markets. At 21:16 UTC on October 13, Kraken said a fix had been implemented and moved the incident to Monitoring.

A chart can load successfully and still be showing the wrong period. Kraken asked users relying on those charts to check candle timestamps and retry or refresh if the data looked outdated.

The notice identifies the affected component as the derivatives user interface; it does not report an order-execution failure.

Source: https://status.kraken.com/incidents/lk3d8t3b26nb

Image: AI-generated editorial illustration, not Kraken premises or a product screenshot.

Bought a Ledger device from CryptoBilis recently? Ledger is asking buyers from the last 90 days to leave devices uninitialized if they haven't set them up yet.

The October 9 notice follows reports of lost funds from users in South East Asia who bought from that reseller. Ledger says it is investigating and has asked CryptoBilis to pause all sales and shipments of Ledger devices as a precaution.

For buyers who have already set up a device, the notice gives a different response: consider moving assets to a new Ledger signer with a new seed. The new seed is part of that recommendation, not just a replacement device.

The investigation remains listed as ongoing. The notice does not establish how the reported losses happened or say that every device from the reseller is compromised. Affected buyers can reach Ledger through its official support site for questions about their situation.

Source: https://support.ledger.com/article/15158192560157-zd

Image: AI-generated editorial illustration, not a photograph of a Ledger device or an affected shipment.

What happens between strategy code and a backtest report?

This short XTester Studio walkthrough follows a Bitcoin strategy using two exponential moving averages through the testing process.

Choose the market, timeframe and test period. Ask the built-in AI assistant to explain the code. Run the simulation, then inspect the equity curve, individual trades and risk measures.

The useful part is being able to move between the strategy and its results in the same workspace. The report gives you more to examine than a single return figure: drawdown, trade history and how the simulated balance changed.

The strategy shown is a demonstration, not a trading recommendation.

Watch the English walkthrough:
https://youtu.be/Dceuzd4olZg

Converting USDT to dollars on Kraken Pro won't move you closer to a lower volume-based trading fee, however large the conversion is.

Kraken's existing rules exclude USDT/USD trades from the 30-day volume used for fee discounts. Trading BTC/USDT does count. Both involve USDT, but the exchange treats them differently: USDT/USD uses the stablecoin fee schedule, while BTC/USDT uses the spot crypto schedule.

The same exclusion applies when exchanging two stablecoins, such as USDG/USDC, or two cash currencies, such as EUR/USD. Those conversions can move substantial amounts through an account without building the qualifying volume a trader expects.

If you're estimating the fees on your next crypto trade, separate those conversions from the trading volume you're counting toward a discount. A busy conversion history can leave you in the same volume tier.

Source: https://support.kraken.com/articles/360039299431-how-do-stablecoin-fx-fees-work-

Image: AI-generated editorial still life.

If Trezor Suite opens an empty wallet after you enter a passphrase, check the spelling before assuming the funds are gone.

With Trezor's existing passphrase feature, the wallet backup and passphrase together determine which wallet opens. A capital letter or an extra space opens a different wallet. Entering that typo doesn't move funds out of the original one.

There is another check worth making: Settings → Networks. Suite reports a wallet as empty when it finds no balance or transaction history on the enabled networks. The correct passphrase can still look unhelpful if the network holding your funds isn't enabled.

Use the same wallet backup, reproduce the exact passphrase, and enable the relevant network. Trezor's guide distinguishes this empty-wallet situation from a “Passphrase is incorrect” error during signing or address verification.

If the passphrase is genuinely lost, Trezor cannot look it up or reset it. The backup alone won't restore that passphrase wallet.

Source: https://trezor.io/support/troubleshooting/trezor-suite-issues/fix-passphrase-wallet-problems-in-trezor-suite

Sent an unsupported token to your Coinbase deposit address? There may be a way to get it back without waiting for Coinbase to list it.

Coinbase's existing asset recovery service can send eligible assets to a self-custody wallet. It only covers certain assets and networks; a successful transfer to a Coinbase address doesn't establish recovery eligibility.

The browser-based tool asks for the network, transaction ID and destination address. If it finds the transaction, you connect the wallet that should receive the recovered funds and review the fees. Coinbase charges a network fee for the recovery attempt, plus 5% of the estimated recovery value above $100. That estimate can differ from the actual market value.

Pay particular attention to the receiving wallet. Coinbase warns that connecting through email or phone sign-in can create a new Base App address instead of opening an existing wallet. The recovered funds go to the wallet connected during recovery, which may not be the one you normally check.

Start from Coinbase's official recovery guide below, and confirm that receiving address before completing the transfer.

Sources:
https://help.coinbase.com/en/coinbase/trading-and-funding/sending-or-receiving-cryptocurrency/recover-unsupported-crypto
https://help.coinbase.com/en/coinbase/trading-and-funding/pricing-and-fees/fees?is_mobile_app=true

Image: AI-generated editorial scene of a hardware wallet, not a Coinbase recovery demonstration. A hardware wallet is not required.

Google's Gemini Notebook can turn your reading material into flashcards, then let you repeat only the cards you missed.

You supply the source material. In the mobile app, that can include a PDF, a website or copied text. When generating a deck, you can select which sources to use, set the difficulty and ask for a particular focus. Someone reading a long report could make a deck about its terminology rather than receive questions about the whole document.

Google announced saved progress and missed-card review in March 2026, under the NotebookLM name. These are existing features on web and mobile, not a new launch today.

Once the cards are ready, you do the remembering. Flip a card, compare your answer, and mark it “Got it!” or “Missed it!” The app remembers your progress if you leave. At the end, “Only cards you missed” gives you a smaller set to work through. For that report, the next pass can concentrate on the terms you marked as unfamiliar instead of starting the whole deck again.

Sources:
https://support.google.com/notebooklm/answer/16958963
https://support.google.com/notebooklm/answer/16296687
https://workspaceupdates.googleblog.com/2026/03/new-ways-to-customize-and-interact-with-your-content-in-NotebookLM.html

Image: AI-generated editorial study scene, not a Google product demonstration.

Buying crypto through Kraken's ACH Instant Buy can take moments. Moving the money back out comes with a seven-day withdrawal hold, even while trading remains available.

The hold follows an amount of money across the account, rather than just the coin bought. Kraken says it applies to cash or crypto equal to the purchase amount. Selling that coin or exchanging it for another therefore doesn't release the held amount for withdrawal.

It also doesn't automatically freeze the whole account. Kraken describes the available withdrawal amount as the total spot balance minus the funds under the ACH hold. An existing unheld balance can still be available to withdraw; the headline account balance includes money that cannot yet leave.

That distinction matters when buying specifically to fund a separate wallet. A completed purchase gives you something to trade on Kraken, but the bank-funded amount isn't immediately available for that onward transfer.

Plaid ACH Instant Buy requires a verified US Kraken account and a supported US bank account in the same name. These are existing funding rules in Kraken's current guides, not a newly announced restriction. The withdrawal screen's tooltip shows the available balance, funding limits and applicable holds, so it is the place to check how much can actually be sent.

Sources:
https://support.kraken.com/articles/how-do-i-use-plaid-ach-for-instant-buy-using-usd
https://support.kraken.com/articles/360000389606-why-is-there-a-withdrawal-hold-on-my-account-

Image: AI-generated editorial bank interior, not Kraken premises.

A group photo with one person blinking no longer has to be discarded. Google Photos can generate an open-eyed version using other pictures of that person in your library.

For these personalized edits, Photos draws on private face groups, the collections that bring together pictures of the same person. A request to remove sunglasses or change a smile can therefore use more than the single frame being edited. Other portraits become reference material.

That gives someone choosing a group portrait a different option from retaking the shot or manually replacing a face. It also explains what the result is: a generated expression informed by other photos, rather than a recovery of what the camera saw behind closed eyelids or dark lenses.

Google introduced these personalized edits in November 2025. Its current Android guide puts conversational editing under Edit, then Ask. Access depends on region and eligibility; users must be adults with a personal Google Account. The guide also requires Face Groups, location estimates, and the Gemini and Ask Photos settings to be enabled.

For an album portrait, an edited expression may be exactly what's wanted. Keep the captured moment too: Google Photos' Save as copy option creates a separate edited picture without changing the original. That leaves both versions available, instead of making the improved portrait the only record of the occasion.

Sources:
https://blog.google/products-and-platforms/products/photos/nano-banana-ai-templates-ask-photos/
https://support.google.com/photos/answer/6128850?hl=en&co=GENIE.Platform%3DAndroid

Image: AI-generated editorial portrait of fictional friends, not a Google Photos edit or demonstration.

A wallet holding USDC but no ETH on Ethereum Mainnet can still make an eligible swap through MetaMask. The network fee comes out of the USDC being exchanged, so the user doesn't have to buy ETH first just to get the transaction moving.

MetaMask calls this a gasless swap. The fee still exists; part of the input token pays it. That can remove a separate top-up transaction, but it won't rescue a balance worth less than the gas bill.

For a swap between networks, the starting side matters. MetaMask's current guide supports gasless swaps originating on Ethereum Mainnet, BNB Smart Chain, Linea, Base, Arbitrum or Polygon. Arriving on a supported network doesn't make an unsupported starting network eligible. The fee has to be handled where the tokens are leaving.

There is also an account change to consider on Base, Arbitrum and Polygon: MetaMask says using gasless swaps there automatically upgrades the account to a smart account if needed. This isn't just a different way to display the fee.

The feature requires Smart Transactions and Estimate balance changes to be enabled, plus Extension version 13.4 or later, or Mobile 7.62 or later. It applies to MetaMask Swaps, not swaps made through other providers. If there's already enough native token for gas, the gasless option isn't offered for swaps.

MetaMask's announcement dates to February 2025; its current guide describes wider network support. For someone moving a token balance, the useful question is whether the starting network and quote let that balance fund its own exit.

Sources:
https://support.metamask.io/trade/swap/gasless-swaps
https://metamask.io/news/metamask-feature-update-gas-station

Image: AI-generated photographic still life of a wallet and phone, not a MetaMask interface or demonstration.

A caption can get every word right and still leave out the sigh that changes the sentence.

Android's Expressive Captions tries to carry some of that missing sound into the text. It uses capital letters for more intense speech and labels sounds such as gasps, sighs and applause. Google's current feature page also describes showing how long a word is held, stretching the spelling to reflect a drawn-out delivery.

For someone watching without sound, those details help distinguish the spoken words from the way they were delivered. A family video message can include a laugh or an excited greeting that an ordinary transcript would flatten. The same approach applies to livestreams, where the creator may not have supplied captions at all.

The feature is part of Live Caption across phone apps. Google says processing happens on the device in real time, including in airplane mode, so captioning a downloaded video doesn't require sending its audio to a remote service.

This is an existing accessibility feature, introduced in December 2024, rather than a new launch. Google's current page lists availability on select devices running Android 14 or later, in the U.S. in English only, with no support for calls. It also warns that captions can be wrong. The extra sound cues offer more context, not certainty about what a speaker meant.

Sources:
https://www.android.com/accessibility/expressive-captions
https://blog.google/products-and-platforms/platforms/android/google-android-expressive-captions/

Image: AI-generated editorial illustration of a fictional viewer, not a Google product demonstration.

ESA's artificial eclipse has a small complication: even inside the shadow, some sunlight gets through.

Proba-3 flies two spacecraft as one observing instrument. One blocks the Sun for the other's telescope. Separating them by about 150 metres lets the telescope see closer to the Sun's edge, where the faint outer atmosphere, the corona, is usually lost in the glare.

But light bends around the edge of the blocking disc. Some of those waves meet in the middle of the shadow and reinforce one another. So the telescope has another disc inside its central lens, just 3.5 millimetres across, to block much of that stray light. A spacecraft-sized sunshade still needs this tiny finishing piece.

The payoff is time to watch things move. A natural total eclipse gives observers on Earth only a few minutes. ESA's April 13 report says Proba-3 makes artificial eclipses lasting around five hours, taking one or two images per minute. By that report, it had collected more than 250 hours of corona observations.

Those sequences let researchers follow individual blobs of plasma, the electrically charged gas flowing away from the Sun, and track how their speed changes. Instead of waiting for the Moon to pass in front of the Sun, they can hold the glare out of the way long enough to watch the flow develop.

Sources:
https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba-3/Eclipse-maker_How_Proba-3_subtracts_the_Sun
https://www.esa.int/Science_Exploration/Space_Science/First_Proba-3_science_surprisingly_speedy_solar_wind

Image: AI-generated editorial illustration of an eclipsed Sun, not a Proba-3 observation.

MEXC will close every remaining position in a batch of perpetual futures markets on October 14, 2026 at 07:00 UTC. Leaving a trade open won't keep it running beyond that deadline.

The exchange's October 10 notice covers these USDT-margined contracts: 1000BTT, BOBA, RON, ZBCN, NPC, TFUEL, SWARM, ZIG, UPROBINHOOD, DEBIT, DELTA, SNT, DBR and GEOD.

MEXC says positions will be closed at the fair price at the time of delisting, and all open orders will be canceled. An unfilled exit order therefore won't remain on the book waiting for its target. The notice specifies the pricing basis, not the price traders will receive.

The same cutoff also applies to the affected markets in Futures Grid Trading and Demo Trading, where available. MEXC asks users to disable the relevant grid bots ahead of time.

For someone using one of these contracts to hedge another holding, the closure has a consequence beyond this account: the other holding can remain while the futures hedge ends. Anyone who wants to choose when to unwind the affected position needs to do so before the exchange's scheduled close.

Source: https://www.mexc.com/announcements/article/delisting-of-1000btt-boba-ron-zbcn-npc-tfuel-swarm-zig-uprobinhood-debit-delta-snt-dbr-and-geod-usdt-m-perpetual-futures-pairs-oct-14-2026-07-17827791539098

Image: AI-generated editorial still life, not MEXC premises or a trading interface.