Which development firms integrate custom tools with Jack Henry, Fiserv or Symitar?
Three kinds of firm do this work, and each goes through a route the core vendor sets. Here is each route, who holds the keys, and what a custom tool may change in your core.
Answered in short
4 things that decide this
- 01Development firms integrate custom tools with Jack Henry, Fiserv or Symitar through each core vendor's own route, under access your institution authorises. Product vendors join Jack Henry's Fintech Integration Network or list on Fiserv's AppMarket. A custom builder such as Hashlogics builds one institution's own tool under the access that institution grants.
- 02Jack Henry replaced its Vendor Integration Program with the Fintech Integration Network (FIN) on 1 July 2025. Under FIN, jXchange serves Jack Henry's three banking cores, and SymXchange serves the Symitar core.
- 03Fiserv's Banking Hub lets developers test core banking APIs in a free, shared environment. Its development environments cover Premier, DNA, Portico and four other Fiserv cores. Fiserv says Communicator Open is a requirement for any financial institution that wants to develop its own applications.
- 04Jack Henry says its customers are responsible for all third-party vendor due diligence, and FIN membership doesn't change that. Interagency guidance from the Federal Reserve, FDIC and OCC, issued in 2023, says using a third party doesn't remove a bank's responsibilities. NCUA guidance covers the planning, due diligence and controls credit unions should have in place.
FIN, jXchange for banks and SymXchange for Symitar
Jack Henry's developer site says the Vendor Integration Program has been replaced. Its successor is the Fintech Integration Network (FIN), effective 1 July 2025. FIN covers the SilverLake System, Core Director, CIF 20/20 and Symitar cores, plus more than 40 other Jack Henry products. Jack Henry says FIN membership isn't a partnership or an endorsement. It runs an Integration Readiness Check before an integration is installed at a customer site.
You'll meet two interfaces. jXchange comes as REST and SOAP APIs and serves the three banking cores. SymXchange is a SOAP web services API for Symitar. Vendors and credit unions can use it to run transactions, inquiries and file maintenance on member accounts. They can also run PowerOn specfiles. So a SymXchange tool can change your member records, not only look them up.
Say you run Symitar and your tool also needs Synapsys or other Jack Henry products. Plan on jXchange for those. Jack Henry says SymXchange doesn't support those integrations.
Your institution holds the keys. Jack Henry's shared-responsibility matrix says SymXchange customers create, revoke and review their own API credentials. They also set each vendor's access controls. In-house jXchange customers do the same, with Jack Henry's help on access controls when they ask. On hosted jXchange, Jack Henry creates credentials when the customer authorises it through a support case.
If your project started under the old Symitar VIP channel, use FIN's support channels now. That channel used the old Vendor Portal and Vendor SharePoint sites. Jack Henry's FIN support page set 31 October 2026 as their retirement date.
Banking Hub to test, Communicator Open to go live
Fiserv's public door is Banking Hub, inside Developer Studio. A Developer Studio account registers you for Fiserv's core banking APIs. You can test them in a free, shared environment. Upgrading to the Connection plan adds a dedicated test environment with more capacity.
Development environments cover Premier, DNA, Signature, Precision, Cleartouch, Portico and Finxact. Fiserv calls Premier the most widely used core account processing platform among US financial institutions. It says DNA serves financial institutions, challenger institutions and credit unions. It designed Portico for credit unions.
API transactions flow through Communicator Open, Fiserv's enterprise services framework, then on to specific, authorised client environments. Fiserv says Communicator Open is a requirement for any financial institution that wants to deploy pre-integrated apps. The same goes for one that wants to develop its own applications. So your bank or credit union needs it before your custom tool reaches the live core.
Your tool can write through these APIs as well as read. Fiserv's Account Service creates and manages accounts and also retrieves account information. Its Party Service manages names, addresses, IDs, tax data and contact details.
DNA has a second route. DNAcreator is Fiserv's developer toolkit for custom apps that integrate with, modify and add capabilities to DNA. It carries the same tools Fiserv uses for its own DNAapps. We found no toolkit like it for Premier on the Fiserv pages we read on 31 October 2026.
Access routes, core by core
From each vendor's own pages, checked on 31 October 2026. Your core, your hosting and your contracts decide what your build can actually touch.
| Core | How a custom tool gets in | Who holds the credentials | What it can change | Watch for |
|---|---|---|---|---|
| Jack Henry SilverLake, Core Director, CIF 20/20 | jXchange REST or SOAP API | Your bank in-house; Jack Henry on hosted, when you authorise it | What your access controls allow | Some integrations also need a batch feed |
| Jack Henry Symitar | SymXchange SOAP API | Your credit union creates, revokes and reviews them | Transactions, file maintenance, PowerOn specfiles | Other Jack Henry products need jXchange instead |
| Fiserv Premier, DNA, Portico and others | Communicator Open APIs, tested in Banking Hub | Not stated on Fiserv's Banking Hub pages; ask Fiserv | Accounts and party data, plus retrieval | Your institution needs Communicator Open first |
| Fiserv DNA only | DNAcreator toolkit | Not stated on Fiserv's DNA apps page; ask Fiserv | Custom apps that modify and extend DNA | Confirm the route during scoping |
When middleware or an aggregator is the better answer
Check what's already built before you pay for a build. Fiserv says many AppMarket apps can be implemented in as little as 30 days. Jack Henry publishes a jXchange Connector for teams developing with MuleSoft.
You can also buy an integration platform. In September 2024, PortX announced Fintech Hub as a pre-integrated app on Fiserv's AppMarket. It uses pre-built connectors between a Premier core, Communicator Open and third-party systems. In October 2024, PortX announced it had joined Jack Henry's VIP. The aim was to reach SilverLake through jXchange and Symitar through SymXchange. If one of those connectors already moves the data you need, buying it is the shorter path.
An aggregator fits when your tool only needs to read. Plaid's Transactions product, for example, retrieves up to 24 months of transaction data. On its Digital Toolkit, Jack Henry creates credentials for major data aggregators on its customers' behalf. You can remove them at any time.
A custom build earns its place when the hand-off is yours alone. One example is a loan step that writes back to Symitar after a staff check. Even then, Jack Henry says some integrations need a batch feed as well as its APIs. For credit union solutions, its Custom Solutions teams can work with vendors on batch and scripted integrations beyond the API. That work is billed at time-and-materials cost. If you need bulk reads, Jack Henry's Operational Data Integration offers customised queries.
Vendor due diligence stays with your institution
Jack Henry's shared-responsibility page says customers are responsible for all third-party vendor due diligence on any API it provides. FIN membership doesn't relieve the customer of that duty. Its FIN FAQ adds that Jack Henry doesn't review a fintech's product functions. It checks an integration only to verify that the code makes correctly formatted API calls. It also checks that the code reacts properly to how the integration methods behave.
Your regulator says the same. The Federal Reserve, FDIC and OCC issued interagency guidance in 2023. It says using third parties doesn't diminish or remove a banking organisation's responsibilities. It sets out five stages: planning, due diligence and selection, contract negotiation, ongoing monitoring and termination. For credit unions, NCUA Letter 07-CU-13, still active, gives examiners a standard framework for reviewing third-party relationships.
So your developer should hand you evidence along with the code. You'll want a list of every credential and who can revoke it. Ask, too, which calls only read and which ones write. Add a log of each write with who approved it. Then get a plan for switching the tool off if the contract ends.
- RequestA member or staff action asks for a change
- HoldKept in the tool's own queue; nothing posted yet
- ApproveA person signs off where your rule requires it
- PostOne call per change, with a unique request ID checked before any retry
- Read backYour core's record is compared with the request
- LogRecords who asked, who approved and what changed
Six stations. Nothing reaches the core before station four, and station five reads the core back to confirm the write landed.
Three kinds of firm, and where we fit
You'll find three kinds of firm. Product vendors join FIN or list on AppMarket, then sell one integration to many institutions. Integration platforms such as PortX sell pre-built connectors. Custom development firms, Hashlogics among them, build one institution's own tool under the access that institution grants.
The same hold-then-release shape runs in production in another industry, at WorkMateAI, an Australian home-services marketplace. Its payments run through Stripe Connect on a hold-and-release model, freeze on dispute and generate chargeback evidence. Every dispute action is audit-logged.
That shape is the one in the diagram above. It sits in front of any write your tool makes to the core. Your build would start with a free scoping call, then a Blueprint: a fixed-fee plan an engineer writes from your real systems. Its fee is credited in full against the build. If the Blueprint doesn't give you a plan you'd act on, you don't pay for it. The first two months of maintenance after launch are included.
Related questions
01Does a developer need to join Jack Henry's FIN to build a tool for one credit union?+
Jack Henry's public pages, checked on 31 October 2026, don't settle that for a tool built for a single institution. FIN is written for fintechs whose integration is installed at mutual clients. SymXchange itself is open to credit unions as well as vendors. The credit union creates the credentials. Confirm your case with Jack Henry's Vendor Relations team before the build is scoped.
02Can a custom tool write to Symitar or a Fiserv core, not only read?+
Yes, where your institution's access allows it. SymXchange runs transactions and file maintenance on member accounts. On Fiserv, the Account Service creates and manages accounts. The Party Service manages names, addresses and contact details. On Symitar, your credit union sets the vendor's access controls. A careful build holds each write until it's approved, then reads the core back after posting.
03How long does a Jack Henry integration take?+
Jack Henry puts a typical new FIN integration at 2 to 6 months from start to finish, sometimes longer. It says the time depends heavily on paperwork and onboarding, the fintech's readiness and the integration's complexity.
Related
- Custom software for credit unions and community banks →What we build beside Symitar, Fiserv DNA and Keystone.
- Banking software development →Ledgers and payment flows around the core you keep.
- WorkMateAI case study →Hold-and-release payments on Stripe Connect, in production.
- What is an idempotency key? →Why each write needs a key that stops it posting twice.
- API integration →Connecting to a system you don't control.
- Will your automation survive an API change? →Building an integration that outlasts the vendor's next release.
