The Maestro alternative for Cardano and Bitcoin
Keep both chains on one API. Flat monthly pricing, requests instead of credits, and an endpoint-level migration map that gets you moved before your keys stop working.
7-day trial on Builder, then $29/mo. Card required, nothing charged before day 7.
Five answers before you switch
What breaks, what does not, how long it takes, what it costs, and how to try it without committing. In that order.
What breaks
Four mechanical things: the base URL, the auth header (X-Api-Key with an nxs_ key replaces api-key), cursor paging on the newer reads (an opaque nextCursor you send back as cursor), and anything built on Transaction Manager webhooks or Managed Contracts, which have no Nexus counterpart.
What does not
Every endpoint concept. Accounts, addresses, assets, pools, scripts, datums, transactions and submit all have a Nexus route, and Bitcoin UTXOs, ordinals, runes and submit do too. Blockfrost SDKs keep working unchanged against /api/v0.
How long it takes
Chain-data reads move in a day or two with the map on this page. Submit is a same-day change. Both APIs run side by side, so you switch reads over one at a time and never go dark.
What it costs
Builder is $29/mo for 2M requests, Growth $79/mo for 10M, Scale $199/mo for 50M with WebSocket streaming included. A request is a request, with no credit weights to model. Market data is a $19/mo add-on.
How to try it without committing
Start the 7-day Builder trial. Card required, nothing charged before day 7, cancel from the dashboard. Point one read at Nexus, compare the payloads, then move the rest.
What Maestro's announcement means for you
Their words, not ours. Three facts from the Sep 18 retirement notice, and what each one means for your integration.
On Sep 18, every endpoint is retired
Bitcoin, Cardano and Dogecoin. API keys stop working the same day. There is no grace period after the date.
Until then, everything runs as normal
Which means you can migrate calmly this week instead of during the panic days before the cutoff. Both APIs can run side by side while you switch reads over.
Open-sourcing comes after the cutoff
Their Cardano stack is promised as open source "in the coming months", after your keys are already dead. Self-hosting later is an option; it is not a migration plan for September.
The endpoint migration map
Every Maestro endpoint you call today, mapped to its Nexus destination. Swap the base URL and the auth header, keep shipping.
| Maestro endpoint | Nexus endpoint |
|---|---|
| /addresses/{addr}/utxos | /api/addresses/{address}/utxos |
| /addresses/{addr}/transactions | /api/addresses/{address}/transactions/history |
| /transactions/{tx_hash} | /api/transactions/{txHash} |
| /txmanager (submit) | /api/transactions/submit |
| /assets/{asset} | /api/assets/detailedInfo?assetPolicy=&assetName= |
| /pools/{pool_id}/info | /api/pools/{poolId} |
| /datums/{datum_hash} | /api/scripts/datum/{datumHash} |
| btc /addresses/{addr}/utxos | /api/btc/addresses/{address}/utxos |
| btc inscriptions by address | /api/btc/addresses/{address}/ordinals |
| btc tx submit | /api/btc/txs/submit |
Following Maestro's pointer to Blockfrost? Nexus speaks the Blockfrost API too: point any Blockfrost SDK at /api/v0 and your code keeps working.
What differs, and what has no equivalent
The map above is the direct matches. These two lists are the rest, so you find them here and not in production.
Same data, different shape
Auth and base URL
X-Api-Key: nxs_... on https://nexus.gerowallet.io, no /v1 segment. Network is a query parameter, not a host.
Paging on newer reads
cursor and limit with an opaque nextCursor. The older reads keep page and pageSize. Never carry a Maestro cursor across.
Address utxo_refs
No reference-only route. Read /utxos and project {txHash, outputIndex} client-side.
Address decode
The address moves to the end of the path: /api/addresses/decode/{address}. Byron addresses report no credentials.
Confirmation tracking
Submit returns and you poll /api/transactions/{txHash}, or subscribe over WebSocket streaming where your plan includes it.
Bitcoin inscription fields
satOffset, vout and txid are parsed out of the satpoint. runes[].runeId replaces rune_id.
Bitcoin mempool UTXOs
Delete the second call. Unconfirmed UTXOs arrive in the main response with status.confirmed=false.
No Nexus equivalent today
GET /policy/{policy} summary root
Every sub-resource (assets, utxos, mints, addresses, accounts, transactions) is mapped. Only the one aggregate document is not.
GET /pools/{pool_id}/delegators/{epoch_no}
Only the newest stake snapshot is readable. Historical delegator lists are not available.
Transaction Manager: turbosubmit, state, history, webhooks
POST /txmanager maps to /api/transactions/submit. The rest does not exist on Nexus.
Managed Contracts (vesting, direct swap, staking, multisig)
Application logic, not chain data. There is no surface to migrate it onto.
Bitcoin utxo_block_height and utxo_confirmations
Not returned on inscription listings.
Need one of these? Email [email protected] before you migrate and we will tell you the date or the workaround.
Maestro vs Nexus at a glance
Same chains, simpler math. Flat requests instead of credit weights, and a platform that is still here after Sep 18.
| Dimension | Maestro (retiring) | Nexus |
|---|---|---|
| Metering | Compute credits, per-endpoint weights unpublished | Requests. One request is one request, even the big ones |
| Entry paid plan | Conductor $49, 4M credits/mo | Builder $29, 2M requests/mo |
| Production tier | Virtuoso $199, 16M credits/mo | Scale $199, 50M requests/mo, WebSocket streaming included |
| Rate limits | 100 req/s on Conductor | 25 req/s with a 250-request burst on Builder. Growth and Scale run 50 and 100 req/s, bursts 500 and 1,000 |
| Chains | Bitcoin, Cardano, Dogecoin | Bitcoin, Cardano and Midnight, live today |
| Push data | Webhooks | WebSocket streaming, snapshot first, then live updates |
| After Sep 18 | All endpoints retired | In production, with a public status page at status.gerowallet.io |
Maestro figures from their last published pricing page. Nexus figures reflect current plans; see the pricing section for detail, including add-ons. Spot an error? Email [email protected] and we will fix it.
Why not the free one?
Koios is a community-run Cardano API and it is genuinely free. For Cardano-only reads under 50,000 requests a day, with best-effort uptime, it is a good answer. Here is where it stops.
| Dimension | Koios | Nexus |
|---|---|---|
| Price | Public and registered plans at $0. Pro ~$29.99/mo, Premium ~$74.99/mo | Builder $29/mo, Growth $79/mo, Scale $199/mo |
| Daily requests | 5,000 public, 50,000 Free with a key, 500,000 Pro, 1.2M Premium | 2M, 10M and 50M per month, no daily reset |
| Rate limit | 100 requests per 10 seconds on public and Free, 250 on Pro, 500 on Premium | 25 req/s on Builder, 50 on Growth, 100 on Scale, with bursts |
| Query timeout | 30 seconds on public and Free, then HTTP 504 | Per-endpoint timeouts behind our own indexers plus Yaci, Koios and Blockfrost as fallbacks |
| Chains | Cardano only | Cardano, Bitcoin and Midnight on the same account |
| Beyond chain reads | Chain data. No market data, streaming, transaction builder or wallet analytics | Market data across 11 DEXes, WebSocket streaming, transaction builder, wallet analytics, MCP server |
| Who runs it | A community of node operators, open source, best-effort support | A.D. Labs, the GeroWallet team, with a named engineer on your migration |
Koios figures from koios.rest/tiers.html, checked September 2026. Koios is also one of the fallback providers behind Nexus chain reads, so choosing Nexus does not mean leaving it behind.
Migration questions, answered
How long does migrating from Maestro take?
For chain-data reads, most teams finish in a day or two using the endpoint map above: same concepts, different paths and auth header. Transaction submission is a same-day change. If you want help, ask for an engineer on the migration and you will get a named person, not a ticket queue.
What replaces MaestroProvider in my code?
The official TypeScript SDK, @adlabs/nexus on npm, covers Cardano, Bitcoin and Midnight over REST. Mesh has a merged NexusProvider, a Lucid Evolution provider PR is open, and code written against Blockfrost SDKs points at the Blockfrost-compatible endpoint at https://nexus.gerowallet.io/api/v0.
What happens to my Maestro keys on Sep 18?
Per Maestro's own announcement, every endpoint is retired and keys stop working that day, across Bitcoin, Cardano and Dogecoin. Nothing on your side survives the date. Anything still calling their API on Sep 19 fails.
Is Nexus free to use?
No. Nexus is paid infrastructure, from $29/mo with a 7-day trial on Builder, card required. Every plan covers Cardano, Bitcoin and Midnight on the same account, and each key is scoped to a single chain and network.
Move before the panic week
Both APIs run side by side until Sep 18. Start the trial today, switch reads over with the map, and be done while everyone else is still opening tickets.