Intro

Custom Bet is a service that enables you to build your own Bet Builder feature, giving punters the freedom to create highly personalized betting experiences. By combining multiple selections—whether within a single match or across different matches—you can offer engaging, flexible betting options that drive both margin growth and player satisfaction.

Check our product sheet to understand Custom Bet on one page.

Key Benefits / Use Cases

• You can customize your odds pricing for the Bet Builder by choosing a specific odds key or using any odds source to define the margin.
• You can enhance your punters' engagement by using our AI-driven pre-built recommendations, or our highly customizable combination options.
• You can choose the best integration solution for your business:

  • API solution (supports SDK) to design your own front end and tailor the experience fully.
  • Front-end widget solution for faster integration into your existing platform. - Reach out to our sales or support team for more information.

2. Supported Sports & Markets

Custom Bet uses a limited number of selected markets provided in our Unified odds feed product for each supported sport.

Check out the Custom Bet Market List page for the detailed list of markets we support.

Note:

• For all Total and Handicap lines, we only support x.5 market lines.
• All Asian outcomes are not supported in Custom Bet, as we do not currently provide calculations for partly-voided outcomes.

Sport	Pre-match	Live	Tournament
Soccer	✅	✅	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
Basketball	✅	✅	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
Tennis	✅	✅	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
Ice Hockey	✅	✅	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
American Football	✅	✅	Custom Bet supports NFL now. Other tournaments coming soon.
Baseball	✅	✅	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
Cricket	✅	✅	Custom Bet supports all tournaments except Test matches.
Volleyball	✅	Coming in November 2027	Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
MMA	Coming soon in May 2026		Custom Bet supports all tournaments for which the specific market is supported in the UOF feed.
Rugby Union		Coming in October

3. Our Solutions

These are the 2 solution you can choose to build your own Bet Builder feature.

Solution	When to choose it?
API	Use this if you want a fully customized front-end experience. Provides maximum flexibility to design your own interface and user experience. Supports SDK
Front-end	Use this if you want fast, easy integration. The widget can be iframed into your website for quick deployment. Ideal if you have limited time or resources and want to test the feature quickly. You can opt for our API solution afterwards when you finish building your own front end. Demo: https://widgets.sir.sportradar.com/custom-bet#matches:(matchId:50852263,sportId:1) Reach out to our sales or support team for more information.

API solution

These are the 4 main API endpoints you can use to build your Bet Builder. Check each page for the detailed guide to each API endpoint.

• Available Selection: Gives you all available markets that can be combined with the Custom Bet.
• Calculate: Returns the odds and probability of the selected combination. Also provides remaining available selections.
• Calculate Filter: Returns the same information as Calculate (odds and probabilities). Additionally, flags selections that conflict with the current combo.
• Pre-Built: Provides AI-powered personalized recommended pre-built combos with odds pricing.
• Voided Recalculation: Gives you precomputed odds for all possible single-void scenarios.

Other Features we support

• Source-Agnostic solution: you can use any odds sources you want, and we will harmonize your single odds with the Custom Bet odds to generate the most competitive pricing. Check here for the guide.
• Multi-match request: combine up to 5 matches with a maximum of 10 selections per match. Check here for the guide.
• Multi-sport request: Multi-sport request: combine up to 5 matches across multiple sports with a maximum of 10 selections per match. Check here for the guide. All sports are supported except Tennis, which is coming in Q3.
• Combination flexibility: You can freely combine any markets as long as they do not conflict. Even if two selections imply the same outcome, we still allow the combination—helping you increase bet volume and reduce ticket rejection rates.

Sports	Source-Agnostic	Multi-match & Multi-sport
Soccer	✅	✅
Basketball	✅	✅
Tennis	Live - Coming soon in June 2026 Pre-match - Coming soon in Aug 2026	Live - Coming soon in June 2026 Pre-match - Coming soon in Aug 2026
Ice Hockey	✅	✅
American Football	✅	✅
Baseball	✅	✅
Cricket	✅	✅
Volleyball	✅	✅
MMA	Coming soon in May 2026	Coming soon in May 2026

4. Combination Rules

• Max 10 selections per match and Max 20 matches in one request. Matches can belong to the same sport or different sports.
• All combinations are allowed as long as they do not conflict, meaning thst the selections cannot happen at the same time.
• If you are not using harmonization (not sending us your single odds), then you will not be able to combine selections that imply same result. You will receive an error message “One or more market selections imply a similar outcome to another market selection.”

5. Environments

Environments	Guideline
Integration	Use this environment for testing and development before release. Note: Since it is also used for ongoing development, testing, and deployments, results may differ from production. Performance and reliability are not guaranteed.
Production	Use this environment for real user traffic and live experiences. Note: Do not use for testing to ensure production requests are processed reliably.

For more information about API availability, access restrictions and functionality related to these, please see the Unified Odds feed integration documentation.

6. API Access & Data Availability

Products Access

Custom Bet is offered per Sport + Pre-match/Live combination. For example, to access both Soccer Live and Soccer Pre-match, you must activate two separate products: Soccer Live Custom Bet and Soccer Pre-match Custom Bet.

Rate Limit

Environment	Default Limit	Pro Package	Premium Package
Production	100 req/sec	250 req/sec	500 req/sec
Integration	100 req/sec	250 req/sec	500 req/sec

⚠️ For higher limits, please contact your commercial representative to upgrade the product.

Data Availability

Event Type	Availablity
Pre-match	Pre-match Custom Bet is available once you receive side markets (markets other than 2-way, 3-way, or totals) from UOF, until handover to Live.
Live	Live Custom Bet is available after handover from Pre-match to Live odds, until the match ends. And you need to book the Live event on our Live Booking Calendar.
Completed matches	Not supported

⚠️ Betpal (Producer 4) is supported on Custom Bet. However, it is strongly recommended to enable the Harmonization feature. Without Harmonization, customers are advised that Custom Bet will use underlying probabilities to form Custom Bet odds and not ALPHA odds probabilities. We recommend all customers to use Harmonization to have the most optimum Custom Bet Odds available.

7. Odds & Margins

How Odds Are Calculated:

1. Calculate correlation: We use simulation data to assess the correlation between all selections. There are three types:

   • Independent: One selection does not affect another.
   • Positively correlated: One selection makes another more likely.
   • Negatively correlated: One selection makes another less likely.
2. Calculate combined probabilities: Multiply the individual fair probabilities of each selection and adjust by the correlation factor to get the combined probability. For example: Combined Probability = Correlation factor * Probability 1*Probability 2*Probability 3*...
3. Convert probability to odds: The combined fair probability is then converted into fair odds = 1/fair probability
4. Apply margin: Finally, a margin is added on top of the fair odds to generate the final odds offered. (See below for 2 margin options).

Margin / Odds Key Configuration

We offer two types of margin and odds key options, but only one can be applied at a time.

Options	What is it?	How to use it?
Harmonization (Recommended)	We use your single odds price to calculate the Custom Bet odds. This will ensure Custom Bet odds are aligned with your single odds and provides consistent, competitive pricing. This approach is source-agnostic, so you can use any odds sources you want. Explanation of source-agnostic solution. For example you want to combine market A and market B, we will use our model to calculate the correlation factor (see the explanation), and multiply it with all your single odds of each selection. Calculation formula = Single odds (Market A) * Single odds (Market B) * Correlation factor.	Simply send us the odds of each single selection in the request. <selection id="sr:match:14736961" market_id="14" specifiers="hcp=1:0" outcome_id="1711" odds="2.4"/> <selection id="sr:match:14736961" market_id="26" outcome_id="70" odds="3.5"/> You can set a max cap on your harmonized odds, so that you can ensure it is within your risk management. Please reach out to the support team and we can set this up for you.
Odds Key Ladder To be deprecated, so please do not use this if you are starting to integrate	Select among four odds key options, and this will be applied on top of the fair Custom Bet odds. The odds key will be used for all Custom Bet odds, and we do not consider your single odds and probabilities adjusted for specific selections via CTRL (pre-match) or Betpal (live).	The Custom Bet ladder will be configurable through Betradar Ctrl (feed options > Custom Bet tab) Please find the mapping of fair odds to Custom Bet odds for each ladder in the chart below.

Odds Key Ladder Mapping

fair odds	Aggressive (105)	Moderate (110)	moderate (flat)	Conservative (115)
1	1	1	1	1
1,001	1,0005	1	1	1
1,02	1,015	1,01	1,01	1,005
1,05	1,04	1,03	1,03	1,02
1,1	1,08	1,07	1,07	1,05
1,2	1,17	1,15	1,16	1,12
1,4	1,36	1,32	1,33	1,28
1,7	1,63	1,57	1,6	1,51
2	1,9	1,82	1,85	1,74
2,5	2,36	2,23	2,25	2,11
3,5	3,25	3	3	2,8
5	4,5	4,1	3,8	3,8
10	8,5	7,5	6	7
20	16	14	9	12
50	40	33	18	25
100	70	50	22	30
1000	300	200	50	100
10000	750	500	70	250
100000	2000	1000	80	500

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8. Best Practices

• Punter Placing a Bet

  • Use Available Selection endpoint to show users all possible markets.
  • When a user selects a combo, call Calculate Filter endpoint to get odds and disable conflicting selections.
  • Before placing a bet, call Calculate endpoint for a fast, accurate odds response.
  • When the punter places the bet, call the Void Recalculation endpoint using the same selections to get the precomputed void combination odds. If one selection is later declared void, use the returned odds to settle/update the remaining valid selections.

  Offering Pre-Built Recommendation

  • Get recommended pre-built combos and display it on the event page or homepage for quick bet placement.
  • For Pre-match Pre-Built recommendations, we recommend caching the odds price for 15 seconds, since Pre-match prices rarely change quickly, which reduces excessive API calls.
  • If you need to update the odds for a specific pre-built, call Calculate endpoint endpoint for a fast response without the need for filtering.

  Handling Settlements & Voided Markets:

  • Store the final accepted custom bet ticket
  • Listen to the feed for settlements of individual markets.

    • Won: all selections are won
    • Lost: at least one selection is lost
    • If one leg is voided, update the price for the remaining selections. You can do this with our Void Recalculation endpoint.
  • The settlement logic should follow the same principles as handling combination bets across different events.