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Deprecated

Harmony Networks Removal

September 25th, 2026

Tatum is decommissioning its hosted Harmony Mainnet S0, Harmony Testnet S0, and Harmony Devnet S0 RPC services following the Harmony Protocol's official decision to sunset the Harmony network and migrate the ONE token to Ethereum.

Developers currently relying on these endpoints for node access, transaction submission, or state queries will need to update their integrations, as Tatum will no longer host Harmony nodes.

📘

Harmony Official Announcement: Harmony to Migrate Its ONE Token

Key Changes & Impact

Harmony validators were permitted to stop operating starting September 10, 2026, at 7:00 a.m. PT. All ONE balances, including wallet holdings, staking delegations, validator rewards, and tokens held in smart contracts, are snapshotted at the network's final block and airdropped as new ONE tokens (ERC-20) to the same addresses on Ethereum Mainnet.

With the network sunset, the hosted Harmony RPC services have reached their End of Life (EOL) and are being retired. Requests to these endpoints will return connection errors, and all associated Tatum RPC routes are being deactivated. Related Harmony features, including gas fee estimation, exchange rates, and malicious address checks, are also being discontinued.

Deprecated Endpoints

The following primary gateway endpoints, regional API routes, and legacy aliases (including one-* aliases and api.tatum.io/v3/blockchain/node/harmony-* routes) are being decommissioned:

Harmony Mainnet S0

  • https://harmony-mainnet-s0.gateway.tatum.io
  • https://one-mainnet.gateway.tatum.io

Harmony Testnet S0

  • https://harmony-testnet-s0.gateway.tatum.io
  • https://one-testnet.gateway.tatum.io

Harmony Devnet S0

  • https://harmony-devnet-s0.gateway.tatum.io
  • https://one-devnet.gateway.tatum.io

Recommended Action

If your application interacts with the Harmony ecosystem or the $ONE token:

  1. Migrate to Ethereum Infrastructure: Update your application endpoints to point to Ethereum.
  2. Update Token Contracts: Use the new ONE ERC-20 token contract on Ethereum Mainnet once it is published by the Harmony team.
  3. Smart Contracts: Multisig safes, liquidity pools, and onchain apps on Harmony cannot be migrated. Refer to Harmony's official channels for guidance on any remaining positions.
  4. Historical Data: If you require legacy historical data from the Harmony network, you will need to rely on archive nodes or ecosystem explorers.