How we selected these companies
Apart from Unknown Gravity, which publishes this page, we included a company only if it meets three criteria, each backed by a source we opened: (1) according to its own website, custom blockchain development for clients is its core business; (2) the company appears in an official company register (in Spain, the BORME, the official gazette of the Commercial Register, or the Commercial Register itself; elsewhere, the national register), and we give its legal name and registration details; (3) there is public, named proof of delivered work: a case or project with the client or partners named on its website, a public repository or a press article. We did not use market-share figures, third-party rankings, ratings or volumes reported by the companies themselves. A register entry shows that a company exists and where it is registered; it does not certify quality or solvency. The numbering is not a quality ranking: Unknown Gravity appears first because it publishes this page, and the rest follow in alphabetical order, Spanish companies first.
01
Unknown Gravity: custom smart contracts and tokenization platforms
Unknown Gravity is a technology company based in Málaga, Spain, and the publisher of this page. It does custom blockchain development: smart contracts, decentralized applications, integrations with existing systems and tokenization platforms, either white-label or built to order. It works on Ethereum and EVM networks such as Arbitrum, Polygon and Base, with ERC-20, ERC-721, ERC-1155 and ERC-3643 when transfers must be limited to verified investors. It also performs smart contract audits scoped to a specific version of the code.
- Where it operates: from Málaga, Spain.
- Registration: Unknown Gravity, S.L., Commercial Register of Málaga, sheet MA-177027; its incorporation was published in the BORME of October 18, 2023.
It is a technology provider, not a regulated intermediary. When the token is a financial instrument or a crypto-asset under MiCA, it works with the issuer's legal advisors and with authorized firms.
Where it fits: you want to own your platform and your contracts, and connect them to the regulated partners you choose. Where it does not: if you need one provider that also places, trades or holds the securities, you need an authorized firm.
02
ioBuilders: tokenization and digital money for financial institutions
According to its website, ioBuilders combines proprietary products with tailored solutions to issue, register, trade and manage tokenized financial instruments and digital money. Its products are Asseto, a tokenization platform for regulated environments, and Naryo, an open-source component that captures events from multiple networks. Its team, the same website says, combines enterprise architects, blockchain specialists and legal experts.
- Where it operates: from Madrid, Spain.
- Registration checked: Iobuilders Blockchain Tech & Ventures, S.L., Commercial Register of Madrid, sheet M-672495. The BORME of August 19, 2026 publishes its latest change of registered office, to Paseo de la Castellana 140, Madrid.
- Public work: its website describes, with the client named, BME's digital corporate bond (smart contracts for the bond sale, the primary and secondary markets and payment events, with delivery-versus-payment settlement) and Cecabank's tokenized deposits proof of concept with ABANCA, Ibercaja, Kutxabank and Unicaja, built on Asseto and a restricted-access network based on Hedera.
Where it fits: banks, asset managers and market infrastructures that want to tokenize financial instruments or digital money in a regulated environment.
03
Peersyst: protocol-level development, CBDCs and wallets
Peersyst describes itself as a company dedicated 100% to developing blockchain projects. According to its website, it works at protocol level (it built the XRP Ledger EVM sidechain and its bridge) and on central bank digital currency (CBDC) pilots, wallets, tokenization and private networks, for protocols, central banks, governments and large companies.
- Where it operates: from Barcelona, Spain, and Andorra, according to its website.
- Registration checked: Peersyst Technology, S.L., Commercial Register of Barcelona, sheet B-540896. Its incorporation was published in the BORME of November 8, 2019, and the move of its registered office to Carrer de Mallorca in Barcelona in the BORME of October 28, 2022.
- Public work: cases with the client named on its website, such as the wholesale CBDC pilot with Colombia's Banco de la República on XRP Ledger and Grupo Nutresa's loyalty program; it also publishes code on GitHub.
Where it fits: your project touches the protocol layer (XRPL, EVM, bridges) or is institutional: central banking, the public sector or large-scale loyalty.
04
LimeChain: protocol engineering and Web3 products from Bulgaria
LimeChain presents itself as a blockchain consulting and development company. According to its website, it does protocol engineering (core protocol development, developer tools and cross-chain bridges), end-to-end product development (smart contracts, decentralized applications, DeFi and real-world asset tokenization), UX/UI design and prototypes.
Where it fits: your project is a protocol or infrastructure (nodes, bridges, developer tools) or a Web3 product that needs engineering at that level.
05
Nextrope: digital asset infrastructure on EVM and XRP Ledger from Poland
Nextrope describes itself as a digital asset infrastructure studio for EVM networks and the XRP Ledger. According to its website, it builds tokenization platforms, stablecoin payments and settlement, DeFi lending protocols, XRPL integrations, backend and data indexing, and supports what it delivers in production.
- Where it operates: from Gdynia, Poland.
- Registration checked: Next Enterprises sp. z o.o., a limited liability company registered on April 11, 2018 in Poland's National Court Register (KRS) under number 0000727128, with its registered office in Gdynia.
- Public work: the Alior Bank case on its website: a durable medium system that records cryptographic proofs of banking documents on Ethereum without publishing the data, in production from 2019 to 2025, according to the case page, with a quote from Tomasz Sienicki, Blockchain Strategy Manager at Alior Bank.
Where it fits: banks and fintechs that need EVM or XRPL contracts integrated with their systems and maintained in production.
How to choose a blockchain development company
Before you ask for quotes, decide which part of the product must live on-chain and who will run it afterward. Then compare proposals against these criteria (the full guide is in how to choose a blockchain development company):
- Ownership of the code and the keys. The contract should assign you the source code and the repository, and the deployment and admin keys should stay under your control, ideally with a multisig. Ask which components belong to the provider and under what license you will use them.
- An audit before production. A smart contract that moves value should be reviewed by someone who did not write it, on the exact version that will be deployed. Ask for the report, the fixed findings and the re-review (more in smart contract audits).
- Experience on your network. Ethereum and EVM networks are not the same as the XRP Ledger, Solana or Hyperledger Fabric. Ask for cases or repositories on the network you will use and for contracts verified on its block explorer.
- Tests and documentation as deliverables. Automated tests, architecture documentation and reproducible deployments should be in the contract, not just the code.
- Regulated roles if you tokenize. The developer does not replace authorized firms. If the token is a financial instrument, it falls outside MiCA (Article 2(4)(a) of Regulation (EU) 2023/1114) and, in Spain, if it is not admitted to trading, its register is administered by an ERIR, the entity responsible for administering registration and recording (Article 8(4) of Law 6/2023). If it is a crypto-asset under MiCA, providing services on it requires authorization as a crypto-asset service provider or being one of the entities listed in Article 60 (Article 59(1) of MiCA). For the firms that fill those roles, see our ranking of tokenization companies.
- Maintenance and operations. Ask who monitors the contracts in production, whether they are upgradeable and how, what the incident plan is and what all of that costs per year.
- Exit from the provider. Agree from the start how the system is handed over to your team or to another provider: documentation, access, keys and infrastructure.
- Milestone-based budget. Scope included and excluded, deliverables per phase and acceptance criteria. Be wary of absolute promises on timing or security.
Frequently asked questions
Which is the best blockchain development company in Spain?
There is no single answer. The companies on this list build custom blockchain software, are on a company register and have published named work. The right one for you depends on the network, the kind of product and whether you also need regulated firms.
How do I check that a blockchain development company exists and is registered?
In Spain, the company must give electronic access, usually on its website, to its legal name and its Commercial Register details (Article 10(1) and 10(2) of Law 34/2002 on information society services). With those details, look up its filings in the BORME on boe.es or check the Commercial Register. Outside Spain, each country has its own register: the KRS in Poland, the Commercial Register in Bulgaria or Companies House in the United Kingdom.
What is the difference between a blockchain development company and a tokenization platform?
A development company builds to order and, if the contract says so, the code is yours. A platform is a product you use under a license or subscription. Some companies on this list do both. None of them replaces authorized firms when the token is a security.
Do smart contracts need an audit if the provider already tests them?
Tests by the team that writes the code do not replace a review by another team. If the contract holds or moves value, audit the final version and repeat the review after every significant change.
Why does Unknown Gravity appear first?
Because it publishes this page. The numbering is not a quality ranking, and none of the other companies paid to appear or reviewed its entry.
Official sources
- BORME, October 18, 2023, Málaga: incorporation of Unknown Gravity, S.L.
- BORME, August 19, 2026, Madrid: Iobuilders Blockchain Tech & Ventures, S.L.
- BORME, November 8, 2019, Barcelona: incorporation of Peersyst Technology, S.L.
- Bulgarian Commercial Register: Lime Labs EOOD, EIK 204318511
- Polish KRS (Ministry of Justice): Next Enterprises sp. z o.o., No. 0000727128
- Spanish Law 34/2002 on information society services, Article 10 (BOE)
Data verified as of October 14, 2026. Registrations change: check each register before you sign. This comparison is published by Unknown Gravity, which is one of the companies listed. Talk to us.