Custom Revit add-ins · C# and .NET

Custom Revit add-ins, built in C# on the Revit API

Ribbon tools for Autodesk® Revit® software, for the tasks your team repeats every week. You get the installer, the guide and the full source code.

Free 30-minute scoping call. Within 2 business days of the call you get a written scope with a fixed price for a pilot or first phase, and an estimate range for anything bigger.

When to build an add-in

The right tool when many people use it every day.

An add-in (some people say Revit plugin) is compiled code that adds your own commands to the Revit ribbon. It takes more work than a script, and it's worth it when the tool has to be fast, reliable and easy to roll out.

  • Many people run it every day or every week
  • It needs a real form: pick lists, previews, settings
  • It must stay fast on large models
  • It reads or writes Excel, SQL or a cloud service
  • It has to keep working through Revit upgrades, with a predictable rebuild each year
  • Your IT team wants a proper installer for every machine

When a script is enough

One task, a few users, and rules that change often? A Dynamo graph or a pyRevit button is quicker and cheaper, and your own staff can edit it.

Not sure? We'll recommend one on the scoping call. Sometimes the answer is a mix: prove the logic in a pilot, then build the add-in.

What we build

Example add-ins for design and construction teams.

Each one follows rules you give us: your naming, your ID scheme, your standard. These are examples of what we build, not past projects.

Sheets and views in bulk

Create every view and sheet for a data hall from an Excel list or a list in Autodesk Forma (formerly Autodesk Construction Cloud), with your naming rules, title block and view templates.

Parameter sync

Push equipment data, tags and loads between Revit models and Excel, CSV or SQL, in both directions, with a report of every value changed.

Rule-based placement

Racks on a grid, sleeves at penetrations, hangers at spacing, all following your rules. Flags spacing below the clearances you set.

Power path sync

Read the one-line equipment list and write A and B feed sources, such as the RPPs RPP-1A-01 and RPP-1B-01, to every rack. Racks with a missing or unknown source are flagged for your engineer to review.

Model audit command

Export warnings, in-place families, CAD imports and naming violations to a report your BIM manager can sort and assign.

Owner numbering schemes

IDs that follow the owner's scheme across every model on a campus, such as B2-DH1-A-01, kept in sync with Excel or the owner's DCIM system.

Data hall rack layout illustrationPlan view of a data hall with four rack rows, contained hot aisles, cooling units on both walls, A and B busways over each row, and one rack labeled DH1-A-03.DATA HALL DH1 · PLANABCDDH1-A-03 · A: RPP-1A-01 · B: RPP-1B-01Cold aisleHot aisle containmentBusway ABusway BCRAH
Illustration: what a rack placement and ID tool produces. Rows, IDs and A/B feeds set by rules, not by hand.

A note on numbering in Revit 2027

Revit 2027 added rule-based numbering for any element (Autodesk Developer Blog). We use it where it fits. Our tools cover what it doesn't: one scheme across every model on a campus, checks for duplicates between models, and sync with the owner's list.

Want to see the logic first? Our rack ID demo and A/B feed check demo run the same rules in your browser.

Browser demos with sample data, not client work.

What you get

Everything you need to own and run the tool.

  • Full source code, delivered to your own Git repository, with build instructions
  • An installer for each Revit version you run
  • A short user guide and a training video
  • A written acceptance test, run together with you
  • A 30-day bug-fix warranty after acceptance
  • No license keys, no license server, no lock-in

A bug is anything where the tool doesn't do what the scope says on the agreed Revit versions.

Who owns what

  • Work made only for you (your add-ins, scripts, content built to your standard, documentation) is assigned to you in writing once paid in full.
  • Our reusable components, including the data center Revit kit, come with a permanent, firm-wide, royalty-free license to use and change them on any project. We keep ownership so we can keep improving them.
  • Open-source parts stay under their own licenses, listed in your handover.

IP and security details

Revit version support

Built and tested for the versions your team runs.

Recent Revit releases changed the .NET runtime that add-ins load into. If your team runs several versions, we build and test an installer for each.

Sources: Revit API forum, Autodesk staff reply, May 2026; Autodesk Developer Blog, Apr 2026.
Revit versionRuntimeWhat we ship
2024 (2023 on request).NET Framework 4.8net48 build
2025.0–.4 and 2026.0–.4.NET 8.NET 8 build
2025.5+ and 2026.5+.NET 10 runtimeSame .NET 8 build, which Autodesk expects to load but doesn't guarantee, so we test on both
2027.NET 10.NET 10 build, installed to Program Files

Microsoft ends .NET 8 support in November 2026. Autodesk expects .NET 8 add-ins to keep loading in Revit 2025.5 and 2026.5, but doesn't guarantee it, and the runtime underneath them is now .NET 10. What this means for your add-ins.

Upgrade & migration

Add-ins broke after an upgrade?

We port, rebuild and package your existing add-ins for each Revit version you run, and test them on sample models before release. We start with a free code review and give you a fixed quote.

Code written by someone else, or by a former employee? That's fine. We read it first and tell you plainly whether to port it or rebuild it.

What a migration includes

  • A review of your code, its dependencies and the Revit API calls that changed
  • One codebase that builds for each runtime you need: net48, .NET 8 and .NET 10
  • Updated add-in manifests, including the add-in isolation settings Revit 2026 introduced (Revit API docs)
  • An installer per version, with Revit 2027 all-user add-ins installed to Program Files
  • Regression tests on sample models and a copy of yours
  • Notes on what changed, so the next upgrade is easier
How we build

Our code-quality standard

A tool that edits hundreds of elements at once has to be safe to run on a live project. Every add-in we deliver follows the same rules.

See how it shows up in a sample scope and acceptance test

  • Undo-safe. Changes run inside Revit transactions you can undo.
  • Preview first. Bulk edits show a preview before anything changes.
  • Logged. Tools log what they changed, so you can check and report it.
  • Tested on real data. We test on sample models and a copy of yours.
  • No telemetry, no license server. The tool doesn't phone home and doesn't stop working if we're gone.
  • Readable source. Your code arrives in your own repository with build instructions, so another developer can pick it up.
Price and time

Example scenarios (our estimates)

Custom add-ins cost $4,000–$15,000. These examples show where a project might land. Your price is fixed in writing after the scoping call.

Our estimates, not past projects. Prices exclude any applicable taxes.
Example scenarioEstimated price (USD)Estimated time
One command, simple form, one Revit version$4,000–$6,0002–3 weeks
Rack layout and ID tool with Excel input, one Revit version$4,000–$7,0002–4 weeks
Several commands, Excel sync, 2–3 Revit versions$7,000–$10,0003–5 weeks
One-line list to Revit power path sync, three Revit versions, installer$8,000–$15,0004–8 weeks
Full interface, external data or an Autodesk Platform Services (APS) link, multi-version installer$11,000–$15,0005–8 weeks

What moves the price

  • How many Revit versions you need
  • A simple button vs a full form
  • External data: Excel, SQL or APS
  • How many commands
  • Documentation and training needs
  • A tight deadline

How you pay

  • Invoices in US dollars
  • 50% to start, 50% on acceptance, due in 15 days
  • ACH or wire; card for smaller items
  • Changes you ask for are quoted first; nothing is billed without your OK
How a build runs

You know the price, the date and what "done" means before we write code.

  1. Scoping call

    Show us the task. We ask how often it happens, how long it takes and who does it.

    30 min · free
  2. Written scope

    Deliverables, a written acceptance test, a fixed price for the pilot or first phase, and an estimate range for the full build.

    within 2 business days
  3. Build

    A short demo every week. You test early versions on your own model. One point of contact: the person writing your code.

    est. 2–8 weeks
  4. Acceptance & handover

    You run the acceptance test. Then source code, installers, guide and video, plus the 30-day warranty.

    at acceptance

How we work and our terms  ·  See a sample scope

What you provide

A little of your team's time, and a model to test on.

  • A person who knows the task and can test the tool, for about 1–2 hours a week
  • A sample model, or access to one
  • Your standards: naming, parameters, ID schemes, title blocks
  • Full Autodesk Revit or the AEC Collection for your users. Revit LT doesn't run add-ins.
  • If the tool uses cloud services: an APS app your firm creates and owns. Some APS usage is billed by Autodesk to your account, and we estimate it before we build.

Hire a Revit developer for the project, not the payroll

Hiring a full-time Revit developer makes sense when years of tool work are queued up. For one tool, or a few a year, a fixed-price project is simpler: no recruiting, no idle time between projects, and a price you know up front.

You still get the full source code, so an in-house developer can take it over later. If you want ongoing help, a monthly retainer gives you an hours bank instead of a hire.

FAQ

Questions buyers usually ask about add-ins

Is a Revit add-in the same as a Revit plugin?

Yes. Autodesk calls them add-ins; many people say plugin or plug-in. Both mean compiled code that adds commands to the Revit ribbon. Revit plugin development and add-in development are the same service here.

Which Revit versions do you support?

Revit 2024 through 2027, and 2023 on request. Revit 2024 (and 2023) run on .NET Framework 4.8, so we ship a net48 build. Revit 2025.0–.4 and 2026.0–.4 run on .NET 8, so we ship a .NET 8 build. Revit 2025.5+ and 2026.5+ use the .NET 10 runtime; we ship the same .NET 8 build, which Autodesk expects to load but doesn't guarantee, so we test on both. Revit 2027 runs on .NET 10, so we ship a .NET 10 build installed to Program Files. If your team runs several versions, we build and test an installer for each.

Who owns the code?

Work made only for you (your add-ins, scripts, content built to your standard, documentation) is assigned to you in writing once paid in full. Our reusable components, including the data center Revit kit, come with a permanent, firm-wide, royalty-free license to use and change them on any project; we keep ownership so we can keep improving them. Open-source parts stay under their own licenses, listed in your handover.

Should we hire a Revit developer in-house instead?

If you have a steady stream of tool work for years ahead, a full-time hire can make sense. For one tool or a few a year, a fixed-price project costs less to start and stop. You get the full source either way, so an in-house developer can take over our code later.

Can you update an add-in someone else wrote?

Yes. We start with a free code review, then tell you whether to port it or rebuild it, and give you a fixed quote.

Could a tool damage our model?

We build to prevent that. Changes run inside Revit transactions you can undo. Bulk edits show a preview first. Tools log what they changed. We test on sample models and a copy of yours. As with any new tool, keep a backup or work on a detached copy the first time.

What happens when the next Revit version comes out?

Autodesk releases a new Revit version every year, and recent releases changed the runtime add-ins load into. On a monthly retainer, yearly upgrades of the tools we built are included or quoted depending on the tier; otherwise we quote them as a fixed-price update. Because you own the source, any developer can do it too.

Do your tools do engineering design?

No. We build software and Revit content. Our tools apply rules and values that your engineer of record provides. Their outputs are drafting and data aids, not engineering calculations, code-compliance reviews or sealed documents. Your licensed professionals review the results and remain responsible for the design.

Can our IT team deploy it?

Yes. You get an installer for each Revit version, and we document what it installs and where, so your IT team can roll it out with the tools they already use.

Do you use AI?

We don't put your models, drawings or project data into AI tools. We may use AI coding assistants on our own code, and a person reviews and tests every line before delivery. AI is used on your data only with your written approval, in tools you approve.

What if you're not available later?

You'll have everything you need to carry on without us: full source in your repository, build instructions, documentation and a recorded walkthrough. There's no license server and nothing that stops working.

All questions and answers

Free 30-minute scoping call

Have a Revit task that should be one button?

Show us the task. Within 2 business days of the call you get a written scope with a fixed price for a pilot or first phase, and an estimate range for the full add-in.