4th Dimension Learning Basics

Key Takeaways

• 4D and FileMaker Pro (FMP) both support multi-user networking, but they take fundamentally different architectural approaches: 4D requires a dedicated Server, while FMP can host peer-to-peer from a regular client copy.
• 4D’s licensing model is based on concurrent connections, not on the number of installed clients — you can deploy unlimited 4D Client applications and only pay for the maximum number of simultaneous users.
• 4D Server automatically distributes and updates the structure file to each client, eliminating manual deployment of database definitions.
• FMP peer-to-peer hosting has hard practical limits (roughly 50 files and 25 concurrent guests, never both at maximum), making it unsuitable for serious production workloads.
• Two editions of 4D Server exist — one that permits design work from clients and one that is use-only — and both support web publishing, though web publishing requires a separate license.
• Choosing between the two platforms is less about raw capability and more about deployment scale, licensing economics, and how much design access you want to grant end users.

Why Networking Architecture Matters

When you move a database from a single machine to a shared network, the architecture you choose determines everything downstream: how you deploy updates, how you back up data, how you recover from crashes, and how much you pay per user. The 4D and FileMaker Pro (FMP) platforms solve the same problem — letting multiple people work with the same data at once — but they solve it in ways that reflect very different design philosophies.

Understanding these differences early saves enormous rework later. A team that prototypes on FMP peer-to-peer hosting and then tries to scale to dozens of concurrent users will hit walls that 4D’s server-centric model was built to avoid. Conversely, a small office with three users may find 4D’s mandatory server requirement to be more infrastructure than it needs. The right answer depends on your scale, your budget, and how much control you want over the client environment.

This section walks through both models in detail, then gives you practical criteria for deciding.

The 4D Server Model: Server-Centric by Design

4D does not offer peer-to-peer hosting. If you want to network a 4D database, you must run 4D Server. There is no supported way to have one 4D client act as a host for others. This is a deliberate architectural choice, and it brings several concrete benefits:

• A single source of truth. All data lives on the server machine. Clients never hold the authoritative copy.
• Centralized backups and recovery. Because the server owns the data files, backup routines and crash recovery are managed in one place rather than scattered across workstations.
• Automatic structure distribution. The 4D Server pushes the structure file (the definition of tables, fields, forms, and methods) to each connected client automatically. The developer does not walk from machine to machine copying files.
• A subset structure on the client. The structure file placed on each client machine is a subset of the main structure — not the full design definition. This keeps client installations lean and limits what a curious user can inspect.

To deploy, you install a 4D Client application on each computer that needs access. There is no per-client cost to the developer — you can create and distribute as many client copies as you like. What you purchase are concurrent connection licenses for the server.

How Concurrent Licensing Works

This is the single most important economic detail of 4D networking, and it trips up newcomers. Licenses are counted by simultaneous connections, not by installed clients.

Suppose you have 100 computers on your network, but you expect no more than 25 people to be using the database at any one moment. You install 4D Client on all 100 machines, but you only need to purchase enough licenses to cover 25 concurrent users. The server admits connections up to the number of licenses you own; the 26th simultaneous user is turned away until someone else disconnects.

This model is generous for organizations with large, intermittent user populations — shift workers, field staff, or departments where only a fraction of the team is active at once. It is less forgiving for organizations where nearly everyone is connected all day.

Two Editions of 4D Server

4D Server ships in two variants, and the distinction matters for how you plan your deployment:

Edition	Design work from clients?	Networking	Web publishing
4D Server (full)	Yes — clients can open and modify the structure	Yes	Yes (separate web license required)
4D Server Application	No — use only	Yes	Yes (separate web license required)

If your developers need to open the database structure from their own workstations and make design changes, you need the full edition. If the server is purely a runtime host and all design happens on a developer machine, the use-only edition is sufficient and typically less expensive.

Both editions support web publishing, but for anything beyond testing you must purchase an additional web license. Treat web publishing as a separate line item in your budget rather than something bundled into the server purchase.

The FileMaker Pro Model: Flexible but Fragile

FMP approaches networking from the opposite direction. A regular FMP file can host itself and other files on a network — this is peer-to-peer hosting, and it requires no dedicated server software. For a handful of users sharing a couple of files, it works.

But the limits arrive quickly. FMP peer-to-peer hosting supports a maximum of about 50 open files and about 25 concurrent guests — and in practice you can never approach both maximums at once. The relationship is roughly a trade-off:

• 1 guest with up to ~48 files open
• 2 guests with up to ~25 files open
• 25 guests with up to ~3 files open

Beyond the raw connection math, peer-to-peer hosting brings operational headaches. Performance degrades as load increases, and database management tasks — backups, crash recovery, consistency checks — become considerably more complex than they are with a dedicated server. When the host machine is someone’s workstation, a reboot or a sleep cycle can disrupt everyone.

FMP Server: The Serious Option

For any serious multi-user deployment, FMP requires the FMP Server, which serves files only. Two consequences follow:

1. You still need a copy of the FMP application to open a file and make changes or use it.
2. You need a copy of the FMP application on every computer that might access the files.

That second point is the key contrast with 4D. If you have 100 computers and expect 25 concurrent users, you still need 100 copies of the FMP application — one per machine. There is no lightweight client equivalent.

FMP Server itself supports up to about 125 open files and up to 250 concurrent guests, though each individual computer can still only open a maximum of 50 files. Note also that FMP Server serves files on a network only; it cannot be used for web hosting those files.

Client Files: The Deployment Difference

The most visible day-to-day difference between the two platforms is what lives on the user’s machine.

With FMP, there is no such thing as a client file. Every user runs a full copy of the FMP application. That means every workstation carries the full weight of the product, and every workstation must be licensed and maintained accordingly.

With 4D, users run a 4D Client application. The client is a purpose-built front end that connects to the server, and it can be distributed freely across your network. The structure file it uses is downloaded and kept current by the server automatically, so you never manually synchronize definitions across machines.

For a small-team IT builder, this is a meaningful operational advantage: rolling out a new form or a new table definition means updating the server, not touching every desktop.

How to Decide: A Practical Checklist

Use these criteria to choose the model that fits your situation.

• Concurrent user count. If you expect more than a handful of simultaneous users, a dedicated server (either platform) is the right call. Peer-to-peer is a prototyping tool, not a production architecture.
• Installed vs. active users. If many machines need occasional access but few are active at once, 4D’s concurrent licensing is economically attractive.
• Design access for end users. If developers need to modify the structure from their own machines, you need the full 4D Server edition. If design is centralized, the use-only edition suffices.
• Deployment overhead. If you cannot afford to install and maintain a full application on every workstation, 4D Client’s free distribution and automatic structure sync is a clear win.
• Web publishing plans. Both platforms can publish to the web, but both require additional licensing beyond the base server. Budget for it explicitly.
• Backup and recovery requirements. If downtime is costly, favor the server-centric model where backups and recovery are centralized.

Where 4D Fits in the Low-Code Landscape

4D occupies an interesting position among low-code and rapid application development tools. It predates most of the modern low-code wave — platforms like Microsoft Power Apps, OutSystems, and Mendix — yet it shares their core promise: let a small team build a custom business application without a full engineering department.

What distinguishes 4D is its long history as a database-first platform. The structure file, the server, and the client are tightly integrated, which is why networking behaves so predictably. For teams that think in terms of tables, relations, and forms rather than drag-and-drop app builders, this model feels natural.

If you are coming from a general-purpose development background, it helps to read up on how relational database management systems handle concurrency and client-server separation — the concepts transfer directly. The Wikipedia article on client-server architecture is a useful primer, and the database server entry explains the division of labor that 4D Server embodies. For the broader category of tools 4D belongs to, see low-code development platforms.

Common Pitfalls to Avoid

• Assuming 4D has peer-to-peer hosting. It does not. Plan for a server from day one.
• Buying licenses by installed client count. 4D licenses are concurrent. Overbuying wastes money; underbuying locks users out at peak times.
• Confusing the two 4D Server editions. If you buy the use-only edition and later need client-side design work, you will have to upgrade.
• Forgetting the web license. Web publishing is not included in the base server price.
• Treating FMP peer-to-peer as production-ready. It is convenient for testing and small groups, but it does not scale and complicates backups.
• Overlooking the per-machine FMP requirement. Every computer that touches the files needs a full FMP application.

Frequently Asked Questions

Does 4D support peer-to-peer networking like FileMaker Pro?

No. 4D requires a dedicated 4D Server for any networked deployment. There is no supported peer-to-peer mode where one client hosts files for others. This is a deliberate design choice that centralizes data, backups, and recovery on the server machine.

How does 4D licensing differ from FileMaker Pro licensing?

4D licenses are based on concurrent connections, not installed clients. You can distribute unlimited 4D Client applications at no cost and purchase only enough server licenses to cover your peak simultaneous user count. FMP, by contrast, requires a full application copy on every computer that accesses the files.

What is the difference between the two editions of 4D Server?

One edition allows 4D Clients to not only use the files but also open and perform design work on the database structure. The other edition, called 4D Server Application, allows use only. Both editions support networking and web publishing, though web publishing requires an additional license.

Do I need to copy the structure file to each 4D Client machine manually?

No. 4D Server downloads and updates the structure file on each client automatically. The structure file placed on client machines is a subset of the main structure, not the full design definition, which keeps clients lean and limits what users can inspect.

Can FileMaker Pro Server host files for the web?

No. FMP Server serves files on a network only and cannot be used for web hosting those files. If web access is a requirement, you need to plan for a separate web publishing solution.

What are the practical limits of FileMaker Pro peer-to-peer hosting?

FMP peer-to-peer hosting supports a maximum of about 50 open files and about 25 concurrent guests, but you can never approach both maximums simultaneously. In practice you might run 1 guest with 48 files, 2 guests with 25 files, or 25 guests with 3 files. Performance and backup complexity also degrade as load increases.