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BLOCKCHAIN DEVELOPMENT · ISBE · SPAIN

Building on ISBE (Spain's Blockchain Services Infrastructure)

ISBE (Spain's Blockchain Services Infrastructure) is a set of public-permissioned blockchain networks led by the Community of Madrid and operated by Alastria. We design and build your Solidity smart contracts for its Main network, test them on a local Besu network and support your company through onboarding. ISBE carries out the deployment through its governance infrastructure.

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WHO WE ARE

At Unknown Gravity, we're not just blockchain developers. We are passionate about blockchain technology.

ARCHITECTURE

What ISBE is and who runs it

ISBE is not a single network but a set of public-permissioned blockchain networks; its official English name is Blockchain Services Infrastructure of Spain. It is led by the Community of Madrid, with NextGenerationEU funds, and implemented and operated by Alastria, which leads its design, deployment and technical governance. It has been running since its launch ceremony on December 18, 2025.

Bare Network

The network with the highest level of compliance. It uses the secp256r1/P256 curve and keeps validator keys in certified HSMs.

Main network (use cases)

EVM-compatible, built on Hyperledger Besu with QBFT consensus and a 2-second block period. It is the network for tokenization and smart contracts: Chain ID 33073 on Mainnet and 11073 on Testnet.

Who reads and who writes

Anyone can query the network through the public explorer. Only identified organizations write to it, with KYB and a did:isbe identifier, through the ISBE Client.

In July 2026, the Community of Madrid put the public investment at 4.7 million euros.

THE NETWORK

What does ISBE offer companies and public administrations?

ISBE presents itself as a regulated blockchain infrastructure. These are its differences from an open public network.

Verified identity

Legal entities from the European Economic Area can join. None operates on the network without completing KYB verification.

No gas fees per transaction

There are no gas fees per transaction. Its fee policy sets a monthly subscription with a transaction quota; transactions beyond it are charged separately.

European regulatory frameworks

Its regulatory compliance page lists MiCA, DORA, LMVSI, ENS and NIS2. Using ISBE does not replace your project's own obligations.

Test environments

It offers DEV, PRE (Testnet) and PRO (Mainnet) environments, and you can build on a local Besu network before onboarding.

USE CASES

What you can build on ISBE

ISBE groups its applications into four families. Its official catalog lists 15 use cases; here are some, as the source describes them.

Tokenization

Assets, carbon credits and digital bonds to finance SMEs. Token City is listed for issuing, registering and transferring bonds on DLT, and Bit2Me STX for issuing and trading tokenized shares and bonds. Both cases involve an ERIR.

Traceability and Digital Product Passport

Supply chain, document certification and the Digital Product Passport (DPP). Bikiot deploys its bicycle traceability solution and iPASS offers a digital passport for products.

Verifiable credentials

Diplomas, micro-credentials and data exchange between administrations and companies. SmartDegrees issues verifiable academic certificates; FutureScreening uses verified identity to curb phone spam.

Certification

Copyright, anti-counterfeiting, supplier verification and B2B contracts. BlockTrace, the joint solution of Lyseis and Wavext, certifies corporate communications and documents.

BENEFITS AND CHALLENGES

Building on ISBE: benefits and limits

ISBE takes care of identity and network governance. In return, it sets rules you should know before designing the contract.

BENEFITS

  • EVM-compatible: standard Solidity contracts, with Hardhat or Foundry
  • Everyone who writes is identified (KYB and did:isbe)
  • No gas fees per transaction
  • Official ERC20, ERC721 and ERC3643 templates

CHALLENGES

  • You cannot deploy on your own: every contract goes through the ISBE Factory
  • ISBE keeps a PAUSER_ROLE to pause your contract: irrevocable in the Proxy Diamond and mandatory in a custom contract
  • A custom contract goes through approval: 2 to 12 weeks depending on the level
  • RPC access is HTTP only, with no WebSocket
  • Interoperability with EBSI is still under development

TECH STACK

Tools for building on ISBE

  • SolidityThe language of the contracts delivered to ISBE.
  • OpenZeppelinIn audited versions, as ISBE's documentation recommends.
  • Hardhat or FoundryDevelopment and testing environments supported by the documentation.
  • @red-isbe/isbe-contractsISBE's official npm library, for the Proxy Diamond pattern (EIP-2535).
  • Local Besu networkTo build and test before your company completes onboarding.

Once your company has access, the application moves from the local network to ISBE by changing the RPC URL.

PROCESS

How we run an ISBE project

01 /

Design

We define what goes on-chain and choose the deployment mode: Proxy Diamond with the ISBE library, or an approved custom contract.

02 /

Development

We write the contracts in Solidity with what each mode requires: the isbe-contracts library for the Proxy Diamond, or audited OpenZeppelin and the PAUSER_ROLE for ISBE in a custom contract.

03 /

Local testing

We test on a local Besu network, without waiting for onboarding to finish.

04 /

Company onboarding

We support you through portal registration, the legal entity representative certificate, KYB verification and the did:isbe identifier. Your company signs the contract with ISBE.

05 /

Handover to ISBE

We prepare the code and documentation for the technical review and, for a custom contract, for approval.

06 /

Deployment and integration

ISBE staff deploy to PRE and then to PRO. We integrate your systems through BaaS or RPC and test in each environment.

WHY UNKNOWN GRAVITY

Your ISBE project, ready for handover

We are a Spanish tokenization and blockchain infrastructure company based in Málaga.

01

Member of Alastria

Unknown Gravity is listed among the members of Alastria, the association that implements and operates ISBE. We do not operate the network or deploy on it: that is ISBE's role.

02

Contracts for tokenized securities

We build with the ERC3643 template and coordinate with the ERIR the issuer appoints to keep the register (Article 8.4 of Spain's Law 6/2023). Unknown Gravity does not play that role.

03

From contract to onboarding

Design, development, testing, handover to ISBE and onboarding support, with a single team.

GUIDES

Guides to Spain's blockchain services infrastructure (ISBE)

FAQ

Frequently asked questions

What is ISBE?

ISBE (Spain's Blockchain Services Infrastructure) is a set of public-permissioned blockchain networks built on Hyperledger Besu. It is led by the Community of Madrid and implemented and operated by Alastria. It has been running since December 2025. Anyone can query its data through the public explorer, but only identified organizations write to it. Its Main network is EVM-compatible and supports Solidity smart contracts.

Who deploys smart contracts on ISBE?

According to its documentation, ISBE staff, through the governance infrastructure of the network: first on PRE (Testnet) and then on PRO (Mainnet). Its ECO1020 policy specifies that the transaction is signed by the verified identity (DID) of your company and executed by the ISBE Factory; with the wizard for pre-certified templates, deployment is immediate. Your company delivers a standard Solidity contract. We design it, build it, test it on a local Besu network and prepare it for the technical review and, for a custom contract, for approval.

Can ISBE be used to issue tokenized securities?

As infrastructure, yes: it offers the ERC3643 template, designed to tokenize shares, bonds and funds, and its catalog lists Token City and Bit2Me STX. But deploying on ISBE is not enough to comply with Spain's Law 6/2023: the issuer must appoint, in the issuance document, an authorized entity to keep the register (Article 8.4), and ISBE does not present itself as one. That entity is an ERIR. In those two catalog cases, the register relies on an ERIR before the CNMV.

How does a company join ISBE?

The company needs a valid digital certificate for a legal entity representative. It registers on the ISBE portal, signs the adhesion contract, completes KYB verification and obtains its did:isbe identifier. Then come the smart contract adaptation, the technical review and the deployments to PRE and PRO. Legal entities from the European Economic Area can join.

How much does ISBE cost?

There are no gas fees per transaction. Fee policy ADM1010 v1.0, dated December 16, 2025 and published in ISBE's legal repository on GitHub, sets a monthly subscription of 500 euros (50,000 transactions), 2,000 euros (300,000) or 5,000 euros (1,000,000), plus 0.020 euros per additional transaction. It is a versioned document that may change: confirm the fees with ISBE before budgeting.

How is ISBE related to Alastria and EBSI?

Alastria implements and operates ISBE, but Alastria's T and B networks are something else, and its ID_Alastria identity is not ISBE's, which uses did:isbe. ISBE states that it is aligned with EBSI, the European infrastructure; interoperability tools are on its 2026 roadmap. Unknown Gravity is a member of Alastria, as we announced in January 2025, and does not operate ISBE.

SOURCES

Sources