A principal-led studio for technology companies, priced on outcomes rather than hours.
The studio
Felag is a boutique engineering studio for funded fintech and technology companies. Our principal-led pods own the architecture and delivery of backends, payment systems and identity infrastructure.
Who we work with
The Series A or B roadmap has an integration nobody on the team has shipped before, and the senior hire will not land in time. We take the integration as a defined outcome and hand it back documented.
The product works until it is busy. We measure the problem first, then fix the cause, and we say so when the answer is a smaller change than the team expected.
MiCA, DORA, the UK regime, GENIUS, VARA, HKMA or MAS has changed what the system must record and prove, and the team needs engineers who have built for one of these regimes before.
The codebase arrived without the people who wrote it. We audit what is there, keep what works, and take ownership of the rest.
The company needs a CTO for one or two days a week to own the architecture, the roadmap and delivery with the team until a full-time hire makes sense.
The agency has the design and the client, and needs a principal behind the backend for the length of the engagement without building that bench itself.
Hourly billing, a dedicated eight-person team as a product, and public-sector tenders scored on headcount.
What we build
We build production backends and their cloud infrastructure. When an existing system struggles under load, we identify the bottleneck before proposing changes.
We build account ledgers, settlement services and card integrations with banks, issuers and processors. The scope includes transaction records and audit trails.
We integrate enterprise sign-on and build account and permission systems for people and software agents.
We build systems that share and verify records across organisations. The Architecture Sprint establishes where a shared ledger is useful and where a conventional database is sufficient.
Go, Rust, Node.js/TypeScript, Python, Solidity; React/Next.js, Vue/Nuxt, React Native/Expo, Flutter; AWS, GCP, Kubernetes, Terraform; EVM (Ethereum, L2s, Polygon CDK), Substrate/Polkadot, Solana, Cosmos, Canton/Daml, Stellar, Bitcoin/Lightning, TON; Postgres, Redis, ScyllaDB/Cassandra, ClickHouse, Kafka, NATS, RabbitMQ, gRPC, GraphQL, REST, websockets, The Graph and custom indexers.
Proof
Work by Felag's founders and principals at Uddug and Gateway.fm, with prototypes and proofs of concept marked as such.
Each case gives its stage, what we built and the facts that add to it, with the notes and sources behind it.
We delivered the Wirex Pay platform end to end: the L2 chain, and the application layer, indexer, oracles and account abstraction behind its non-custodial debit cards.
The engineering was built to support Wirex's MiCA alignment; we have not taken the system through an audit under MiCA. The L2BEAT listing and the partnership announcement below are the public record.
We designed the RPC proxy that served Opera and 1inch in production, with a cache layer and rate limiting.
Both figures are the peak observed in production, aggregate across all clients of the proxy, during 2021 to 2022. The latency is the average over the heavy requests only.
Two workstreams for one client. We designed and built account-abstraction wallets that people open with their company's single sign-on, and an identity system for AI agents on a major cloud platform.
The client is not named. The linked case study is published by Gateway.fm and covers the agent identity workstream only.
We built the backend API behind Infinex's Synthetix PerpsV3 integration. It takes in the PerpsV3 contract events and serves market data, order events and trading history to the app over REST and WebSocket.
We built the application layer for Humanity Protocol, an identity network.
The transaction rate is the peak observed in production, aggregate across the chain, during 2024 to 2025.
We built a shared prover used across several ZK protocols and L2 ecosystems, including EY Nightfall, Polygon zkEVM, Miden and Iden3.
The protocols served were Polygon zkEVM, Polygon Hermez, cdk-erigon, Miden and Iden3, including EY Nightfall. The cost effect of spot capacity was not measured, so no saving is claimed.
The founders led Gateway.fm's Platform department and a second engineering department, accountable for the architecture and the delivery of their products.
Uddug had grown to 15 people when it was acquired in June 2024, and the team joined Gateway.fm as its Platform department.
Ten months as DeepNode's fractional CTO, designing its decentralised AI infrastructure through the January 2026 token launch and exchange listing.
The request rate is the peak observed in production, aggregate across the network, during the engagement.
Uddug built the whole NFT platform behind Arsnl.art and the NFT launches on it.
Uddug also handled the technical delivery for several other artist drops on the platform. 'Geometries' is the one named here, and sales figures are not stated.
The founders' own exchange project of 2017 to 2018, and the push oracle first developed for it.
The exchange was roughly 70 percent built when the investor withdrew in the 2018 crypto winter, and the project ended there.
Names
Clients and products we built for, and the protocols our systems served. Open a name for the relationship and the case behind it.
Client for the payments platform and its L2 chain.
Ran on the RPC proxy we designed.
Ran on the RPC proxy we designed.
Client for the event infrastructure and backend.
Client for the application layer.
A fractional CTO engagement.
Served by the shared prover.
Received the push oracle we designed.
Received the push oracle we designed.
A pull-based price feed and a verifiable-randomness oracle.
The tokenised-finance product we led to revenue.
Ran on the RPC proxy, and served by Gateway Yield.
Ran on the RPC proxy we designed.
Grant work, including JuniDB.
Grant work.
The technology behind the launch, with Snark.art.
Uddug helped with the launch.
The NFT platform and its launches.
Smart contracts.
An NFT launch platform for established artists, later a Uddug client.
The protocol behind Infinex.
Served by Gateway Yield, the staking infrastructure we ran.
Served by Gateway Yield, the staking infrastructure we ran.
Served by Gateway Yield, the staking infrastructure we ran.
Served by the shared prover.
Served by the shared prover.
Served by the shared prover.
The record
Andrew builds and runs a crypto micropayment system and a network of faucets.
Andrew Skurlatov and Mikhail Manko start working together and launch YourAdsMedia, a crypto ad network.
The founders start ICEX, their own exchange, where the push oracle is first developed.
The founders start Uddug on the ICEX core team.
Andrew becomes technical lead and CTO of Snark.art, an NFT launch platform that later becomes a Uddug client.
Andrew joins Gateway.fm as one of its first engineers.
Uddug is acquired, and the team becomes Gateway.fm's Platform department.
The departments close and the team leaves.
Felag starts as the restart of Uddug, with Pavel Dodonov and Andrey Solovov as principal engineers and partners.
The full history: 4 eras and 25 projects, from a 2014 faucet network to Felag
Andrew and Mikhail met in Limassol in 2014 and have built companies together since 2015.
Andrew designed, built and ran a micropayment system and a network of faucets for Bitcoin, Litecoin and Dogecoin, earning about $10k a month at its peak.
The founders' crypto ad network, product and platform built by Andrew and Mikhail.
The founders' own exchange, with a team of 25. It was roughly 70 percent built when the investor withdrew in the 2018 crypto winter. The push oracle first developed for it later shipped for Wirex Pay, Infinex, LUKSO and Lumia.
Andrew Skurlatov and Mikhail Manko founded Uddug in 2018 on the ICEX core team, and it grew to 15 people. NFT launches by the team collectively raised $100M+.
Andrew was technical lead and CTO of Snark.art, an NFT launch platform for established artists, with a team of five. Snark.art later became a Uddug client.
Andrew was lead backend engineer at Kitec, building Go microservices with gRPC, message queues and WebSockets.
Andrew was lead developer of the high-load backend behind Kickstox, a fantasy sports platform.
Uddug took on grant work for Web3 Foundation and Protocol Labs, including JuniDB, an IPFS-backed data layer for Substrate.
Uddug built the technology behind the OG:Crystals launch end to end, in collaboration with Snark.art.
Uddug helped with the launch of Marscatsvoyage.
Uddug built the whole NFT platform and handled the technical delivery of several artist drops on it, including Frank Stella's 'Geometries'.
Uddug built the smart contracts for Metazoku in 2023.
We built the event infrastructure and backend API behind Infinex's Synthetix PerpsV3 integration, under Infinex proposal XIP-9.
Uddug built a mobile wallet for Pandoshi, as a consulting partner of Gateway.fm.
Andrew joined Gateway.fm in 2021 as one of its first engineers. In June 2024 Uddug was acquired and the team became Gateway.fm's Platform department; the founders ran ~25 people across two departments. In 2026 the departments closed and we left.
A cache layer and rate limiting at 140k+ requests per second at peak, with 50 ms average latency on the heavy requests.
Andrew led backend engineering as Head of Backend, ~15 people, on a backend serving 100K+ requests per second at peak.
We led the Presto tokenised-finance product to revenue and built its stablecoin, RWA, DEX and payments blueprints.
We built an EVM event-indexing code-generation platform that became the standard across most of the company's projects.
A push oracle with multi-asset prices every 500 ms for Wirex Pay, Infinex, LUKSO and Lumia; a pull feed at about 1,000 requests per second and verifiable randomness for ApeChain. The figures are the peak observed in production, aggregate across clients, during 2023 to 2025.
The L2 chain, launched in August 2024, and the application layer, indexer, oracles and account abstraction behind its non-custodial debit cards.
We built the application layer for Humanity Protocol, an identity network with 9M+ users.
We built a shared prover used across several ZK protocols and L2 ecosystems, including EY Nightfall, Polygon zkEVM, Miden and Iden3, with GPU and CPU autoscaling on AWS spot capacity.
Account-abstraction wallets with enterprise single sign-on, and an identity system for AI agents on a major cloud platform, both proofs of concept.
Ten months designing DeepNode's decentralised AI infrastructure, measured at about 5,000 requests per second, through the January 2026 token launch and exchange listing at $140M+ fully diluted valuation at launch.
Andrew presented a proposal for EVM compatibility on the Canton Network to its super-validators.
We ran Gateway Yield, the infrastructure behind $1B+ locked in staking, serving Lido, Gnosis, Stellar and Canton.
Felag was founded in July 2026 as the restart of Uddug. Pavel Dodonov and Andrey Solovov joined as principal engineers and partners.
What it costs
Fixed-price sprints, builds and technical reviews. Monthly retainers for pods and fractional CTO work, with deliverables agreed in the statement of work (SOW). Prices in US dollars, excluding VAT.
A 60-minute session with a founder to understand your system, priorities and constraints. If an Architecture Sprint is useful, we agree its scope. Detailed specification and costed build options are part of the paid sprint.
A founder
One to two weeks with a principal that end in a build decision: spec, architecture decisions, risk register and costed build options, with the fixed-price build or the pod that follows quoted from them.
A principal
A principal in the CTO seat for agreed days each week, spread across Monday to Friday, until a full-time hire makes sense. The CTO owns the architecture and the engineering roadmap, runs engineering process and delivery with your team, and represents the technology to the board and investors.
Andrew, Pavel or Andrey, never a contractor
The build after the sprint, on a monthly retainer with deliverables agreed each month in the SOW, and a team sized to the scope.
A principal, with senior and specialist engineers as the scope needs
A review of the system and the team behind it against a scope fixed in advance, for investors and acquirers who need findings they can act on.
A principal
Every build starts with a paid Architecture Sprint, and fixed-price builds are quoted from a completed sprint. Your engagement is led by one of our principals, identified in the statement of work. Any replacement requires your consent.
How we work
Four steps, each with a clear output.
Free, with a founder. If a sprint is useful, we agree its scope.
One to two weeks with a principal, paid in advance and credited against the build.
Taken together on the sprint output: a fixed-price build or a pod.
A pod with deliverables agreed each month, or a fixed-price build.
Fractional CTO work and due diligence start from the same workshop and go straight to a scoped proposal.
Who we are
Andrew sets Felag's technical direction, leads the architecture on its engagements and steps in as fractional CTO. He has spent 15 years in software, ten of them in blockchain. He co-founded Uddug in 2018 and, after it was acquired, ran ~25 people across two departments as VP of Platform and Yield.
Mikhail looks after partnerships and deals at Felag, from the first call to the signed contract. He has spent 13 years running teams, products and operations. He co-founded Uddug with Andrew in 2018, saw it through its acquisition, and then headed the platform team for Gateway.fm's tokenised-finance product.
Pavel leads engineering on Felag's engagements. He came to software after a decade of scientific R&D and 20+ published papers. In nearly four years at Gateway.fm he went from Go backend engineer to Backend Lead, and led the architecture of the shared prover that several ZK networks ran on.
Andrey leads delivery on Felag's engagements. He started at Uddug, building smart contracts and payments architecture. At Gateway.fm he spent more than two years as Blockchain Dev Lead, shipping production systems for DeFi, oracle, L2 and identity clients, from the contracts down to the services behind them.
We bring in specialist contractors when a project needs them, always led by one of us.
Questions we are asked
No. Sprints and technical due diligence are fixed price, pods and fractional CTO work are monthly retainers, and the workshop is free.
One of the people above leads every engagement and is identified in the SOW. Contractors join for QA, DevOps and additional development when the scope needs them, always led by one of us.
With a free technical workshop with a founder. For a build, the next step is a paid Architecture Sprint. Fractional CTO work and technical due diligence go straight to a scoped proposal.
The spec, the architecture decisions, the risk register and the costed build options are yours. The sprint is paid in advance and credited in full against a pod or fixed-price build signed within 30 days of its delivery.
The contract is with FELAG LLC, a Georgian limited liability company with identification number 426561829 and registered office at Georgia, Gardabani Municipality, Poladaant Kari Village, 4th Street, Lane II, N 11. The founders work from the Netherlands and Cyprus.
For monthly delivery pods, deliverables are reviewed and accepted with you at the monthly review, against the SOW, and scope changes agreed there go into the next month's SOW. For an Architecture Sprint or technical due diligence, the principal takes you through the output at delivery, and you accept it or return a written list of gaps within five business days. A fixed-price build is accepted milestone by milestone, against criteria agreed in the sprint, on the same five-day review after each demo. A review with no list counts as acceptance. Any change to a fixed-price scope is agreed in writing before work on it starts, with a fixed quote for its effect on the price and the timeline.
Yes. We built the Wirex Pay platform and the application layer behind its debit card programme, engineering that supported the client's MiCA alignment. We have not taken a system through an audit under MiCA, and we say so before a sprint starts.
Yes. We use AI tools and our own development framework. A principal reviews the work and remains responsible for the agreed deliverables.
Next step
Tell us about the system and your deadline. We start with a free technical workshop with a founder, and reply within two working days.