The short answer
Stay with an IDX vendor for as long as “listings on our website” describes what you need. Move to a custom build when listing data has to live inside software you control: when you combine several MLSs your own way, when the website is itself the product you sell to agents, or when search, CRM and other features have to work on the same data. There is also a middle path, a RESO Web API data vendor feeding your own front end, that many teams should try before building a full pipeline.
Three ways to get listings into your site
| IDX plugin or hosted IDX | Data vendor API + your front end | Direct MLS feeds + your pipeline | |
|---|---|---|---|
| What you run | The vendor's search and listing pages on your site | Your own website or app, reading listings from the vendor's API | Your own ingestion, database, search index and front end |
| Published cost examples | $49 per month (Buying Buddy) to $149 per month (IDX Broker Elite); Realtyna $99 per month plus $850 one-time setup | SimplyRETS $49, $99 or $199 per month plus a one-time $99 connection fee; Repliers $199, $299 or $399 per month for one MLS; plus development | MLS license fees, for example MLS PIN $100 per month for a broker, $525 per month for a vendor; a delivery platform where the MLS uses one; plus development and operations |
| Where the data lives | In the vendor's product | With the vendor; your app queries it | In your own systems, under your MLS license terms |
| Control of search and design | What the vendor offers | Full control of the front end; data model is the vendor's | Full control of both |
| Engineering needed | Little or none | A front-end build | A data pipeline, search and a front end, then ongoing upkeep |
The full fee tables, with every vendor and MLS we could find a published price for, are in our MLS and IDX cost guide, and the cost calculator adds them up for a specific setup.
Signs an IDX vendor is still the right choice
- You are one agent or a small brokerage and the goal is listings and lead capture on your website.
- You have no developers and do not want any. A plugin is a subscription; a custom build is software you own and have to keep running.
- You work in one MLS and its listings, shown the way the vendor shows them, are enough.
- The monthly fee is small next to what the site earns. At the published prices above, a plugin costs less in a year than a few days of development at the $50 to $99 per hour Clutch reports for software companies in the United States.
Signs it is time to build
The website is the product
If you provide websites to many agents, each with their own branding, you are running a platform, not a website. Our real estate SaaS case study is that situation: white-label IDX websites for individual agents across US and Canadian boards, which grew from 5 agents to 200+ after the data layer was rebuilt.
You need several MLSs as one dataset
Each board has its own fields and status values, and a property can be listed on more than one. Combining them means normalizing schemas and removing duplicates yourself. Our W3|re case study covers a brokerage that needed four MLS systems (NTREIS, Stellar MLS, ARMLS and REcolorado) in one pipeline.
Other features have to work on the listing data
A CRM that knows which listings a lead viewed, valuation models, or search in plain language all need the data inside your own systems. In the W3|re project, conversational search and an automated valuation model were built on top of the unified pipeline, after it existed.
Search has to be faster or different
Map search, auto-suggest and filtering over millions of listings need a search index and a cache that you tune for your users. The real estate SaaS case study reports 2M+ listings with search responses under 200 ms after the rebuild.
What changes in cost when you build
Moving off a plugin replaces one subscription with three kinds of cost:
- MLS license fees, in a different category. A company that sells a product built on MLS data to agents is licensed as a vendor, and vendor fees are higher than broker fees. Stellar MLS charges $450 per office per year, capped at $7,500 for a broker back-office feed and $7,500 per product per year for a vendor product; ARMLS gives brokerages five free feeds and says vendor products are typically $1,000 to $1,500 per product per month.
- A delivery platform, if your MLS uses one. Trestle charges $30 per month for broker data feeds and $100 per month for other feeds; MLS Grid says you only pay the license fee required by your MLS.
- Development and upkeep. This is usually the largest part and it does not end at launch: feeds change, boards retire old interfaces, and sync jobs need monitoring. We do not publish a price for it, because it depends on how many boards you combine, how fresh the data must be and what you build on top.
Before any of that, you need the data license itself. Our guide on how to get MLS data access for your app covers license types, broker sponsorship and the approval steps.
The middle path
A data vendor API lets you build your own front end without running an ingestion pipeline. It suits a brokerage that wants its own design and search experience in one or two markets. Its limits are the vendor's: which MLSs it covers, how it models the data, and its pricing per MLS or connection. If you later need several boards merged your own way, or data inside a CRM or valuation model, you are back to deciding whether to build the pipeline.
Questions to answer before you decide
- Is the listing search a feature of your website, or is the website a product you sell?
- How many MLSs do you need now, and in two years?
- Which license category would each MLS put you in, and what does it charge for that category?
- Which features need listing data in your own database: CRM, alerts, valuation, analytics?
- Who will keep the feeds running after launch?
Frequently Asked Questions
Is an IDX plugin cheaper than a custom IDX build?
Yes, by a wide margin, for a single site. Published plugin plans run from $49 per month to $149 per month, while a custom build adds MLS license fees, sometimes a data vendor, and development. A custom build is a decision about control and capability, not about saving money.
When should a brokerage switch from an IDX vendor to a custom build?
When the listing data has to live in software the brokerage controls: several MLSs merged into one dataset, branded sites for many agents from one platform, or features such as a CRM or valuation that work on the same data. If listings on a website is the whole requirement, stay with the vendor.
Is there an option between an IDX plugin and a full custom pipeline?
Yes: a RESO Web API data vendor feeding your own front end. For example, SimplyRETS publishes plans at $49, $99 or $199 per month plus a one-time $99 connection fee and Repliers at $199, $299 or $399 per month for one MLS. You build the website; the vendor supplies the data.
Do MLS fees change if we build our own product?
They can. MLSs license the same data in different categories, and a product sold to agents is usually a vendor product. Stellar MLS, for example, charges $450 per office per year, capped at $7,500 for a broker back-office feed and $7,500 per product per year for a vendor product.
What ongoing work does a custom IDX build need?
Feeds have to be monitored and kept in sync, schemas change, boards retire old interfaces, and search has to be tuned as listing volume grows. Plan for a team, in-house or contracted, that keeps the pipeline running after launch.
Prices were taken from the vendors' and MLSs' public pages and re-checked on October 9, 2026. Fees change, so confirm current pricing with each provider.
