Which MEV Relayers Support Bundles on Solana?
Short answer: Jito's block engine, and Harmonicas a Jito-compatible alternative. Several RPC providers accept bundles too, but they forward them to Jito. Many "fast send" services only take single transactions, which is not the same thing.
A bundle is a set of transactions that land together, in order, in one block, or not at all. That is what a launch needs: create the coin and buy it from several wallets before anyone else can.
Services that accept bundles
| Service | Bundles | Tip | Notes |
|---|---|---|---|
| Jito block engine | Yes, up to 5 tx, atomic | SOL transfer to a Jito tip account, min 1,000 lamports | The default for bundles on Solana. No auth key needed for default sends (1 req/s per IP per region). |
| Harmonic | Yes, revert-protected | Priority fee (compute unit price), no tip transfer | Alternative block engine; SendBundle is Jito-compatible. Public JSON-RPC at /api/v1/bundles; bundles are forwarded across its regions. |
| Helius sendBundle | Yes, up to 5 tx (forwarded to Jito) | Transfer to a Helius tip account, min 5,000 lamports | 1 credit per send, 5 requests/s per project. Choose a Jito region with the jito-region header. |
| Fast-send services (e.g. QuickNode Lil-JIT) | No, single transactions | Varies | Good for landing one transaction quickly; no all-or-nothing guarantee across several transactions. |
bloXroute and other relays list bundle-related features in their Solana APIs; check their current docs for atomic multi-transaction support before relying on them for a launch.
Bundle rules that apply everywhere
At most 5 transactions
Jito accepts up to 5 transactions per bundle, and so do the services that forward to it. Larger launches are split across several bundles.
All or nothing, in order
Transactions run in the order you list them, inside one slot. If any one fails, none of them land, so you never pay for half a bundle.
The tip is part of the bundle
On Jito the tip is a SOL transfer to one of 8 tip accounts, inside a transaction of the bundle. The minimum is 1,000 lamports; competitive bundles pay far more.
Only some leaders take bundles
A bundle can only land in a slot whose leader runs software connected to that block engine. That is why bundles sometimes wait a few slots.
Jito block engine endpoints
| Region | Endpoint |
|---|---|
| Global (nearest) | https://mainnet.block-engine.jito.wtf |
| Amsterdam | https://amsterdam.mainnet.block-engine.jito.wtf |
| Dublin | https://dublin.mainnet.block-engine.jito.wtf |
| Frankfurt | https://frankfurt.mainnet.block-engine.jito.wtf |
| London | https://london.mainnet.block-engine.jito.wtf |
| New York | https://ny.mainnet.block-engine.jito.wtf |
| Salt Lake City | https://slc.mainnet.block-engine.jito.wtf |
| Singapore | https://singapore.mainnet.block-engine.jito.wtf |
| Tokyo | https://tokyo.mainnet.block-engine.jito.wtf |
Get the tip accounts with getTipAccounts on /api/v1/getTipAccounts and pick one at random. Send from the region closest to your server.
Harmonic endpoints
| Region | Endpoint |
|---|---|
| Frankfurt | https://fra.be.harmonic.gg |
| London | https://lon.be.harmonic.gg |
| Amsterdam | https://ams.be.harmonic.gg |
| Newark | https://ewr.be.harmonic.gg |
| Tokyo | https://tyo.be.harmonic.gg |
| Singapore | https://sgp.be.harmonic.gg |
| Salt Lake City | https://slc.be.harmonic.gg |
Which one for a token launch?
For a Pump.fun launch, Jito is still the safe default: it is what most validators run, and every bundle tool supports it. Harmonic is worth adding as a second route if you write your own sender, since a bundle can only land when the slot leader is connected to the engine you sent it to.
Set the tip from the live floor, not a guess: see the Jito tip calculator. New to bundles? Start with what a Jito bundle is.
Skip the plumbing
SolBundler builds the bundle, sets the tip and lands your create and buys in the same block from 20+ of your own wallets. Free to sign up; 1% on trades.
How SolBundler uses Jito →Questions
Which relayers accept bundles on Solana?
Jito's block engine is the main one. Harmonic runs an alternative block engine with a Jito-compatible SendBundle API. Some RPC providers, such as Helius, accept sendBundle and forward it to Jito. Services built for fast single transactions do not land atomic multi-transaction bundles.
What is the maximum number of transactions in a Jito bundle?
Five. Transactions execute in order, within one slot, and all-or-nothing.
What is the minimum Jito tip?
Jito enforces a minimum of 1,000 lamports per bundle. Bundles at that level rarely win when others compete for the same slot; check the live tip floor before sending.
Do I need a Jito auth key to send bundles?
No. Default sends no longer need an approved key. Without one you get 1 request per second per IP per region; higher limits are available on request.
Is Harmonic compatible with Jito code?
Mostly. Harmonic says its SendBundle gRPC and auth flow are backwards compatible with Jito's searcher protos, so existing code usually needs a new endpoint. Tips work differently: Harmonic uses priority fees instead of a tip transfer.