Over the past two years we have run a hackathon, a mainnet build campaign, and three bounty sprints. Judging all of them taught us what a good reactive integration looks like: it fits the project it sits in, it beats the alternatives a team could have reached for, and it runs.

Reactive Circuit takes that judgement somewhere else. Instead of hosting the event, we pay for integrations built at other major hackathons. Win there, send us the project, and if the integration holds up, collect a bonus from us.

Short Version For Newcomers

A reactive contract subscribes to event logs on other chains. When a log it cares about appears, it runs Solidity logic and can fire a callback: a transaction it sends, by itself, to a contract on another chain.

That makes one class of problem much easier and leaves plenty of others untouched. So the questions we ask about a submission are whether the subscription is doing real work, whether the project would have been simpler without us, and whether the thing actually ran. Callbacks in a block explorer answer the last one. The first two are a judgement call, which is why there is a review rather than a script.

Ideas Over Deployments

Our first hackathon ran from September 9th to November 4th 2024 on DoraHacks. Eight weeks, 397 registered hackers, 74 submitted projects, workshops, judges, and an announced $35K grant pool for projects worth scaling further.

It worked on its own terms. Flash Profit Extractor, the Dynamic NFT Royalty System and a batch of no-code experiments came out of it. What it did not tell us is how many of those 74 projects had a contract that actually ran in production conditions. Submission count and execution count are different numbers, and in 2024 we mostly had the first one.

Tracks, Specs, Transactions

September 2025 was the next shape: a build campaign aimed at Reactive Mainnet, with tracks and partners instead of one open field. Judging closed in early November with 154 registered builders, 31 final submissions, and 2,971 tracked transactions. That third figure is the interesting one, because it came off the chain rather than off a signup form.

Then we narrowed further. Reactive Bounties 2.0 replaced the open brief with three back-to-back two-week sprints, each with a written spec and real constraints. The first sprint drew 23 submissions, and the program wrapped on January 13th 2026. Twenty-three is a smaller number than 397. It is also a number where every entry had to satisfy a spec somebody wrote down in advance.

Six With Callbacks

The clearest version of that shift happened at an event we did not run. At the UHI9 hookathon, a good share of teams reached for Reactive. Rather than tallying who mentioned us, the judging checked whether each project's reactive contract had actually fired a callback on-chain. Six cleared that floor.

Passing that check is not the same as being good, and the six vary. Epoch-close settlement, pool management handed to a reactive contract, time-based triggers, cross-chain hedging, risk scoring built from past events.

Line up the four numbers and the trend looks like decline: 74, then 31, then 23, then 6. We read it the other way around. What shrank is the set of things we were willing to count, and what grew is what each counted thing proves. A submission proves someone filled in a form. A fired callback proves the subscribe, react and callback loop survived contact with a real chain, real gas and real event logs.

How Reactive Circuit Works

Four steps:

1. Pick an event from our list. It is short by design: events where a reactive integration makes sense, not every hackathon running that month.
2. Build your project there, using Reactive for something the project actually needs. The subscription has to do real work, the callbacks have to fire, and the code has to be open.
3. Win a prize. Main track, sponsor track, regional award: if the organizer awarded it and published the amount, it counts.
4. Claim within 14 days of results, through the application form.

The bonus is 10%, 20%, or 30% of the cash prize you’ve already won, paid in REACT on top of it. Which level depends on how relevant the use case is, how well the integration is built and documented, and the scale of the event. Larger prizes sit at the lower end, for budget reasons rather than quality ones.

Two awards per event at most, going to the two highest-placed Reactive projects. Before paying, we check three things: the demo runs, the repository is public, and the integration is real, meaning a reactive transaction on Lasna or mainnet plus the callback it produced on the destination chain. Testnet counts the same as mainnet, though we do not reimburse gas or fund deployments on either.

Prize decisions belong to each event and weigh more than engineering, so a strong integration can land outside the bracket for reasons that have nothing to do with the code. If your project used Reactive and did not win, send it anyway. If the integration is genuinely interesting, we may award something for it.

Events On Radar

Two events are listed as of October 30th 2026, and we add more as they are confirmed.

ETHGlobal Mumbai, November 5th to 7th, timed around Devcon India. Three days in person with ETHGlobal's usual partner prize tracks, and the most straightforward fit on the list.

Uniswap Hook Incubator, cohorts back to back through the year. Eight weeks each: six of instruction, then a capstone hookathon and a demo day. Nearly 500 graduates and more than 400 hooks across the first seven cohorts, and that extra runway is a large part of why callbacks could be verified at UHI9 in the first place.

The spring circuit is the next thing to watch. ETHDenver has not published 2027 dates yet, and it goes on the list the day it does. If you're heading to something that is not present on our list, let us know before you build. If a reactive integration fits the event, we would rather add it to the list than turn down good work after the fact.

Questions

Telegram is open for questions about the program; technical questions are better suited to our dev channel. We never message first asking for anything. The only account that speaks for the program is the one linked above. 

About Reactive Network

Reactive Network is an EVM automation layer built around reactive contracts — event-driven smart contracts for cross-chain execution. It runs on CometBFT consensus, providing deterministic finality with roughly one-second block times while maintaining full EVM compatibility. Reactive contracts subscribe to event logs across EVM chains and execute Solidity logic automatically when matching events occur, issuing cross-chain callback transactions when their conditions are met.

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