Who offers consulting for integrating blockchain into legacy systems?

Decision-makers keep asking us a deceptively simple question: who can actually plug blockchain into our existing ERP, mainframe, data warehouse, and cloud stacks without breaking production? Below is a current, concrete guide to the firms and platforms that do this work in 2025—and how they approach integration, privacy, interoperability, and operations at enterprise scale.

Summary: A 2025 field guide to the consulting and platform providers that integrate blockchain with legacy systems, with concrete offerings, credible case studies, and implementation patterns you can use now.

The landscape at a glance

Global systems integrators (SIs) with enterprise change muscle and accelerators
Protocol specialists who build and run networks (Ethereum/Quorum, Hyperledger Fabric, Corda)
Cloud providers offering managed blockchain stacks and node infrastructure
Open-source orchestration and interoperability layers that bridge old and new

Global SIs and consulting leaders

IBM Consulting
- Where they fit: modernization on z/OS, LinuxONE, Red Hat OpenShift; deep Hyperledger Fabric expertise and long-standing governance/tooling for permissioned networks.
- Notable: IBM provides enterprise support subscriptions specifically for Hyperledger Fabric (24x7 SLAs), reflecting a shift from “blockchain platform SaaS” to hardened support plus consulting. IBM’s Fabric story also emphasizes Linux on Z/LINUXONE for security and throughput-sensitive workloads. (platform.softwareone.com)
Deloitte
- Where they fit: end‑to‑end IT integration and operations; heavy public-sector and regulated-industry footprints; alliances that unify legacy data silos with modern data and web3 rails.
- Notable: 2025 collaboration with Palantir to break down back‑office silos—a pattern we see reused for blockchain data and tokenized workflows that must reconcile with ERP/finance systems. (www2.deloitte.com)
EY
- Where they fit: tokenization + public‑chain privacy, “OpsChain” productized APIs to plug existing systems into blockchain without replatforming.
- Notable: EY OpsChain Traceability and ESG expose enterprise‑grade APIs (including Polygon/Ethereum options) and privacy layers (ZK proofs) for public chains; EY reported API-driven token mints at significant daily volumes—exactly the sort of throughput you need for production integrations. EY is also rolling OpsChain Contract Manager on Polygon PoS, with an Ethereum mainnet path. (blockchain.ey.com)
KPMG / PwC
- Where they fit: audit-grade data pipelines and integration governance; getting on‑ and off‑chain data into assurance/compliance workflows.
- Notable: KPMG Chain Fusion normalizes multi-chain data for audit; KPMG in India partnered with The Hashgraph Group to deliver Hedera-backed enterprise solutions (DID, Digital Product Passport, sustainability). PwC co‑built a production travel solution with Kayak and Blockskye, using blockchain as the “single source of truth” across booking to reporting. (kpmg.com)
Accenture, TCS, Infosys, Wipro, Capgemini
- Where they fit: large‑scale delivery and accelerators spanning multiple DLTs; strengths in industry solutions and legacy integration.
- Notable:
  - TCS Quartz provides gateways and devkits for tokenization, CBDC pilots, and DLT coexistence with core systems. (tcs.com)
  - Wipro Slingshot spins up Fabric/Quorum/Corda stacks across clouds and claims significant provisioning/time‑to‑MVP reductions, helping teams integrate with monitoring, messaging, and OAuth out of the box. (wipro.com)
  - Infosys is a Hyperledger Certified Service Provider with live identity/credential networks at scale—useful when blockchains must dovetail with enterprise IAM and HR stacks. (infosys.com)

Protocol specialists and networks you can hire

ConsenSys (Ethereum/Quorum/Besu)
- Why they matter: the go-to for enterprise Ethereum stacks (public and permissioned). Quorum is now a ConsenSys offering; case studies include komgo (commodity trade finance) and Covantis (agri-commodities operations), built to integrate with big‑name commodities, banks, and ERPs. (consensys.io)
R3 (Corda)
- Why they matter: Corda is optimized for regulated data-sharing with privacy among known parties, and R3’s professional services plus partner SIs deliver in financial market infrastructure (CBDC pilots, RLN, collateral mobility).
- Where to look: R3’s use‑case directory lists production and pilot programs (e.g., CBDC experiments and regulated liability networks) frequently requiring core banking and Swift integration points. (r3.com)
Hyperledger FireFly (via services from Kaleido or SIs)
- Why it matters: FireFly is an open‑source “Web3 supernode” that gives you event‑driven APIs, digital asset/tokens, off‑chain data flows, and connectors for Fabric, Besu/Quorum, and more. It’s explicitly designed to bridge ERP/mainframes/apps with blockchains by delivering reliable event streams, token APIs, and orchestration. Kaleido offers managed FireFly and multi‑protocol environments. (github.com)

Cloud providers that reduce plumbing

AWS: Amazon Managed Blockchain (AMB)
- What you get: managed Hyperledger Fabric networks and public‑chain (Ethereum) connectivity, with ordering service durability built on QLDB tech, VPC endpoints, and KMS-backed identity. This is particularly useful if you’re integrating from VPC‑bound ERP/data platforms. (aws.amazon.com)
Google Cloud: Blockchain Node Engine + Blockchain RPC
- What you get: fully managed Ethereum nodes (full/archive), automatic upgrades for network hard forks, metrics into Cloud Monitoring, and a JSON‑RPC service for high‑throughput dApps. Handy when you need predictable node ops tied into existing SRE/observability stacks. (docs.cloud.google.com)
Microsoft Azure: where it stands in 2025
- Azure retired its managed Blockchain Service in 2021; today, Microsoft steers enterprises to ConsenSys Quorum Blockchain Service and offers Azure Confidential Ledger (a managed, TEE-backed tamper‑evident ledger) for immutability/logging use cases. Plan Azure blockchain builds through partners (e.g., ConsenSys) and/or open-source frameworks on AKS. (redmondmag.com)
Oracle: Oracle Blockchain Platform Enterprise Edition (OBP EE)
- What you get: a Kubernetes‑deployable, customer‑managed Fabric 2.5 LTS distribution with enterprise bits for resiliency/security across multicloud and on‑prem, which matters for data‑sovereignty or ERP‑adjacent deployments. (blogs.oracle.com)

Interoperability: connecting private ledgers, banks, and public chains

Swift + Chainlink CCIP
- Why it matters: in 2023–2024, Swift demonstrated how its existing messaging and connectivity—used by 11,500+ institutions—can bridge to public and private blockchains via Chainlink’s CCIP, using existing back‑office systems. For legacy estates, this pattern lets you pilot tokenized assets without ripping out core flows. (swift.com)
Hyperledger Cacti
- Why it matters: a graduated Hyperledger project that provides an interoperability toolkit to orchestrate cross‑DLT transactions (Fabric ↔ Besu/Quorum ↔ Corda, etc.) without a common settlement chain. If your portfolio spans multiple ledgers, Cacti gives you a vendor‑neutral path to cross‑network asset moves and data‑sharing. (github.com)

Integration patterns that work with legacy estates

Below are practical patterns we deploy and see in production. They’re boring by design—and that’s a feature when you run SAP, Oracle, or mainframe systems at scale.

Event-driven “outbox/CDC → Kafka → Web3 gateway → chain”

Pattern: Capture changes from your operational databases (Oracle, SQL Server, PostgreSQL) via CDC tools (e.g., Debezium) into Kafka topics, then trigger FireFly to mint tokens, notarize documents, or submit smart‑contract calls. This decouples ERP transactions from on‑chain latency/failures. (github.com)
Why it’s robust:
- CDC sources are log‑based, minimizing impact on transaction systems, and preserve ordering semantics you’ll need for audit. Confluent’s managed CDC connectors (V2) keep this approach current. (docs.confluent.io)
- FireFly converts blockchain events into reliable enterprise event streams you can subscribe to from apps/services, maintaining parity between systems of record and on‑chain state. (hyperledger.github.io)

Managed connectivity to reduce node/SRE toil

Use AMB (Fabric) for VPC‑native networks with KMS‑anchored identity and a durable ordering service; or use Google Cloud Blockchain Node Engine and RPC for Ethereum to avoid babysitting clients and hard‑fork upgrades. (aws.amazon.com)

Public‑chain privacy with enterprise APIs

When you need public verifiability and scale but can’t leak business data, use privacy tech (ZK circuits) and API gateways like EY’s OpsChain suite for tokenization/traceability on Polygon/Ethereum without rewriting your core apps. (ey.com)

Cross‑network/“bridged” workflows

If business units or partners live on different chains, Cacti provides a vendor‑neutral framework to transfer assets/share state atomically across chains; for interbank/tokenized‑asset pilots, Swift+CCIP lets you reuse existing Swift back‑office integration. (hyperledger-cacti.github.io)

Performance tuning on Fabric

Fabric v2.x introduced decentralized chaincode lifecycle and improved private data patterns; block size, ordering, and contention dramatically affect latency/throughput—recent peer‑reviewed modeling shows mean response times can swing from ~1–25s based on arrival rates and parameter choices. Treat network parameters as a capacity-planning exercise, not defaults. (aws.amazon.com)
Research continues to propose DAG‑aware execution and dependency scheduling to lift throughput under contention—useful intelligence when evaluating vendor claims on Fabric performance. (Research insight; validate vendor support before committing.) (arxiv.org)

Who to call, and for what

“We need a production tokenization/traceability pilot in 90 days, with SAP/Oracle data feeding public chains under confidentiality.”
- EY OpsChain (API‑first), plus a FireFly gateway and CDC/Kafka bridge from ERP to token mint/burn/transfer workflows. (blockchain.ey.com)
“We’re a bank/market infra exploring CBDC/RLN/collateral with strict privacy.”
- R3 professional services or R3 partners; use Corda for regulated data‑sharing, and plan Swift/CCIP interoperability as you experiment with public liquidity rails. (r3.com)
“We run on AWS with strict VPC boundaries and IAM guardrails.”
- AMB (Fabric) for permissioned networks; combine with AWS KMS‑anchored identities and VPC endpoints, plus Debezium‑to‑Kafka for ERP change events. (aws.amazon.com)
“We want a multichain strategy but don’t want to build bespoke plumbing.”
- Hyperledger FireFly and Hyperledger Cacti together: FireFly for application‑level orchestration and token APIs, Cacti for cross‑DLT transactions. Kaleido can host/manage both across clouds. (github.com)
“We need a managed Ethereum node layer tied to our SRE/observability stack.”
- Google Cloud’s Blockchain Node Engine and Blockchain RPC (Ethereum) with Cloud Monitoring; integrate with your existing incident and metrics tooling. (docs.cloud.google.com)

Concrete examples (with precise setups)

SAP order lifecycle notarization with public‑chain receipts

Setup: SAP S/4HANA writes order events to an operational DB; Debezium streams row‑level changes into Kafka; FireFly subscribes and pins a hash of each order to Polygon PoS for receipt/audit via OpsChain Traceability APIs. Business data stays off‑chain; tokens or NFTs represent physical goods or milestones; ZK proof layer masks sensitive fields. Result: immutable audit line, no SAP code forks, minimal ERP load. (blockchain.ey.com)

Private trade finance on permissioned Ethereum; bank connectivity via Swift

Setup: A Quorum/Besu network runs komgo‑style flows; Swift+CCIP allows banks to test instructing transfers and servicing tokenized assets from existing Swift rails; ERPs post documents via API and hashes are notarized. Outcome: reuse legacy back‑office + Swift connectivity while testing digital asset settlement. (consensys.io)

Hyperledger Fabric for supply chain provenance with IAM and VPC controls

Setup: AMB creates a Fabric 2.2+ network; organizations join via proposals/votes, identities anchored in AWS KMS; off‑chain payloads in IPFS with hashes on‑chain; Kafka topic to fan‑out events to downstream analytics. Outcome: strong governance and private data collections without exposing internal networks. (aws.amazon.com)

Multichain orchestration for asset lifecycle + cross‑DLT transfers

Setup: FireFly provides token APIs and event bus across Besu and Fabric; Cacti executes atomic asset transfer between the two ledgers (e.g., Fabric holds internal warranties; Besu handles external marketplace tokens). Outcome: preserve privacy on Fabric, tap public EVM liquidity when needed. (github.com)

2025 emerging practices worth adopting now

API‑first integration over bespoke SDKs
- Choose providers exposing hardened APIs (EY OpsChain is a good benchmark) to let enterprise integration teams plug in via standard gateways and CI/CD. (blockchain.ey.com)
Treat node ops like commodity plumbing
- Managed Fabric or Ethereum nodes save months of SRE toil and smooth hard‑forks; build your value above the node layer. (aws.amazon.com)
Formal capacity planning on Fabric
- Tune block size/timeout, endorsement policies, and private data strategies; validate with load tests that mimic real transaction inter‑arrival times. Recent modeling underscores how parameter choices swing response times by an order of magnitude. (arxiv.org)
Interop by design
- Assume you’ll straddle permissioned and public networks. Build with Cacti/CCIP compatibility from day one so you can later connect to other ecosystems or liquidity without re‑architecture. (github.com)
Azure strategy update
- If you’re an Azure‑first shop, remember the managed Blockchain Service was retired; plan around Quorum services from partners and Azure Confidential Ledger for immutable logs, plus AKS for open‑source stacks. (redmondmag.com)

Buyer’s checklist: 12 questions for your RFP

Which ledgers do you implement in production today (Fabric/Besu-Quorum/Corda), and which interoperability toolkits (Cacti/CCIP) do you support? (github.com)
Show a reference deployment that integrates with SAP/Oracle or a mainframe via CDC/Kafka—include error handling and replay. (github.com)
How do you enforce privacy on public chains (ZK, off‑chain payloads, on‑chain hashes)? Provide a data classification and key management plan. (ey.com)
For Fabric, what chaincode lifecycle, endorsement, private data, and ordering configurations do you recommend for our TPS/latency and why? Cite load-test results. (aws.amazon.com)
What’s your approach to Swift/banking connectivity for tokenized assets? Demo a CCIP‑based flow if capital markets are in scope. (swift.com)
Which managed node services (AMB, Node Engine/RPC) do you use, and how do you integrate with enterprise observability and incident response? (aws.amazon.com)
How do you version and roll back smart contracts and token schemas across environments?
Can you demonstrate audit‑grade data lineage from ERP row change → Kafka event → on‑chain receipt → report? (docs.confluent.io)
Provide a production support model (SLAs) for ledger upgrades and critical vulnerabilities; if Fabric, do you offer an enterprise support subscription? (platform.softwareone.com)
Show cost drivers (compute/storage/egress/gas/KMS/DevOps) and sensitivity to traffic spikes.
Provide an interoperability roadmap to avoid future vendor lock‑in. (hyperledger-cacti.github.io)
Security posture: HSM/KMS use, IAM boundaries, enclave/TEE options (e.g., Azure Confidential Ledger) for sensitive logs. (azure.microsoft.com)

How 7Block Labs engages

As a blockchain software consultancy, 7Block Labs focuses on integration-first delivery:

Architecture sprints to map CDC/Kafka feeds from your systems of record into FireFly or protocol‑native APIs; we target a deployable blueprint in 2–3 weeks.
Cloud-native ops: AMB (Fabric) or Google Node Engine/RPC (Ethereum) where appropriate, with observability and incident workflows tied into your current SRE stack. (aws.amazon.com)
Privacy and data‑minimization: off‑chain payloads, on‑chain proofs, and ZK‑based confidentiality patterns on Polygon/Ethereum when public verifiability is required. (ey.com)
Interoperability by default: Cacti/CCIP patterns to ensure you can move assets and data across ledgers as partners or regulators evolve. (github.com)

We typically stand up a working skeleton—events flowing from ERP to chain with audit‑proof receipts—in 6–8 weeks, then iterate on governance, security, performance, and rollout to partners.

Final thought

In 2025, integrating blockchain into legacy systems is no longer about one-off pilots; it’s disciplined, API‑first engineering that treats ledgers as another reliable system component. Pick partners with credible production references, embrace managed connectivity where it reduces risk, and build for interoperability on day one. That’s how you get value without rewriting your enterprise.