Message Costs on Reactor

Message Prices

Note: Prices are subject to change

How Reactor Pricing Works

Reactor pricing is usage-based and predictable.

When you call the Reactor Gateway contract on your source, you pay:

1. The normal gas fee on that source to make the call (your cost, like any contract call). Not applicable when the source is web.
2. The Reactor fee for the action you’re asking Reactor to perform.

That Reactor fee is collected up front, onchain, at the time of the call.

After that payment is accepted, Reactor:

• Executes the requested action (cross-chain call, RNG, web request, etc.),
• Pays destination gas to deliver and finalize the result,
• Persists the response onchain if applicable.

Because the fee is collected first, you always know the cost of a given action before you trigger it. There are no surprise invoices later and no post-settlement billing.

What’s Included in the Price

The per-message price for a destination covers:

1. Guaranteed delivery/execution on the destination
Reactor will submit and finalize the message on the destination for you — you don’t need to hold native gas on that destination.

2. Destination gas for that action
Reactor pays the gas on the destination.

3. Onchain routing and orchestration
Reactor logic runs entirely onchain. There is no offchain “runner” you have to trust.

4. Reliability and retry logic
We monitor and retry delivery until it finalizes (within the limits described below).

In short: If you can call the Gateway and it accepts payment, Reactor will take it from there.

Gas Execution Caps

To keep pricing predictable for everyone, Reactor enforces a maximum amount of gas it will consume on the destination per action type:

• Cross-chain calls and RNG requests
  Up to 250,000 gas on the destination.

• Web requests that persist data back onchain
  Up to 2,500,000 gas on the destination.

• Web requests that do not persist data back onchain
  These are treated as outgoing only.” Since no onchain write is performed at the destination, these are not limited by destination gas in the same way.

Why this matters: these caps let us quote simple, flat prices for common actions without metering every opcode or byte for normal use.

If your use case needs more than these caps (for example, very large state writes or multi-application fanout), reach out to the Reactor team so we can work with you on a custom / premium action that will be priced separately according to your use case.

Short-Term Gas Volatility vs. Sustained Gas Spikes

Blockspace prices move. Reactor smooths that for you.

Short-term volatility (hours)

If destination gas briefly spikes for a few blocks or a few hours, Reactor will generally honor the displayed price and absorb the difference.

This keeps your automation stable and prevents noisy “surge pricing” during normal market churn.

Sustained spikes (days or weeks)

If destination gas remains abnormally expensive for an extended period, Reactor may adjust pricing for that destination or for specific high-cost actions.

When pricing changes, it changes before you execute:

• The updated fee is required and collected up front in the Reactor Gateway call,
• You see it onchain at the moment you trigger the action,
• Reactor will not perform the action unless that updated fee is paid.

You are never surprised after the fact, and you don’t owe a balance later. You simply choose whether or not to approve the updated cost at call time.

This model lets us do two things at once:

• Keep predictable pricing most of the time,
• Protect the network from week-long gas crises on expensive destinations (for example, Ethereum congestion).

Per-Caller / Per-Action Adjustments

Most traffic fits cleanly within the posted pricing table.

However, Reactor reserves the right to quote different pricing for a specific caller or specific action when that usage is materially more expensive to fulfill. Examples include:

• Extremely large payloads or calldata-heavy writes,
• Requests that always hit high-gas execution paths on a destination,
• High-frequency “anchor to Ethereum mainnet now” actions during congestion,
• Attempts to treat Reactor as bulk calldata storage.

In these cases, the Reactor Gateway will require a higher fee for that particular call before accepting it.
If you don’t agree with the fee, you simply don’t send the transaction. If your scenario falls into any of the above or something different, reach out to the Reactor team and we can help develop a solution to match your needs.

Why Reactor Can Offer Flat Pricing for Most Destinations

A common question is: “How can Reactor quote something as simple as $0.10 for most destinations?”

Key reasons:

1. You fund the request.
   You pay the fee up front when you call the Reactor Gateway. That fee includes delivery.

2. Reactor covers destination gas for you.
   Destinations outside Ethereum generally have low, stable execution cost for capped calls. For those destinations, we can map that cost to simple dollar-denominated tiers ($0.10, $0.25, $0.30, etc.).

3. Everything runs onchain, efficiently.
   Reactor’s routing/verification/execution logic runs 100% onchain, which is low-cost to operate at scale. There’s no hidden offchain runner fleet or node operator incentives we need to maintain or pay.

4. Built-in gas caps.
   By capping destination gas per action (250K / 2.5M), we make sure a single “expensive” message can’t blow up the economics for everyone else.

Because those economics are predictable, we can make pricing predictable.

FAQ

Do I need to hold gas on the destination?
No. You only need to pay once on your source when calling the Reactor Gateway. Reactor handles gas on the destination as part of the fee you already provided.

Can my price change after I’ve already paid?
No. The fee is collected up front. If Reactor accepts your call and fee, that action will be executed.

Why would my quoted fee ever change?
Two reasons:

1. The destination’s gas cost has stayed abnormally high for multiple days or weeks.
2. Your specific usage pattern is outside normal bounds (huge calldata, very high gas operations, extremely high frequency to an expensive destination, etc.).

In those cases, the Gateway will simply require a higher fee for that call. You’ll see it before you pay.

What happens during brief gas spikes?
For short-lived spikes (think hours), Reactor generally absorbs the difference so your workflows don’t flap in price.

What if I need more than 250K gas (or 2.5M gas for web → chain persistence)?
That becomes a premium/custom action. We can still do it, but it will be priced separately and quoted at call time. Additionally, you can reach out to the Reactor team to work through your scenario and come up with a solution that works for your use case.

Summary

• Pricing is predictable, onchain, and visible at the moment you call the Reactor Gateway.
• The posted per-destination fees include delivery, destination gas (up to the cap), and reliability/retry.
• Reactor smooths short-term gas volatility for you.
• If gas stays painfully high for a long stretch, or if you’re doing unusually heavy actions, the Gateway may quote a higher fee for that specific call.
• You’re never invoiced after the fact, and you’re never forced to execute at a price you didn’t see.

This model is designed to be predictable for normal usage while still protecting the network (and you) during extreme conditions.