> ## Documentation Index > Fetch the complete documentation index at: https://docs.gomaestro.org/llms.txt > Use this file to discover all available pages before exploring further. > Get Bitcoin transaction output information with mempool awareness including pending and confirmed states. # Transaction Output Info (Mempool-aware) ## OpenAPI ````yaml bitcoin/mempool-monitoring-api/openapi.json get /mempool/transactions/{tx_hash}/outputs/{output_index} openapi: 3.0.3 info: title: Bitcoin - Mempool Monitoring API description: >- Maestro's Bitcoin Mempool Monitoring API offers core indexer endpoints with mempool awareness, providing real-time visibility into unconfirmed transactions, enabling developers to build responsive, fee-optimized, and mempool-aware applications without managing their own node infrastructure. #### Key Features: - **Real-Time Transaction Monitoring:** Track unconfirmed transactions instantly as they enter the mempool, providing immediate insights for enhanced user experience. - **Optimal Fee Estimation:** Analyze current mempool conditions to help users set appropriate transaction fees, ensuring timely confirmations and cost efficiency. - **Network Health Analysis:** Monitor mempool size and state to detect network congestion and anomalies, aiding in informed decision-making regarding transaction timing. - **Custom Transaction Selection for Miners:** Utilize mempool data to prioritize transactions with higher fees, maximizing profits during block construction. #### Key Benefits for Developers: Developers can enhance their applications and improve user experience through real-time blockchain insights and optimized transaction processing. license: name: Apache 2.0 url: https://www.apache.org/licenses/LICENSE-2.0.txt version: v0.1.0 servers: - url: https://xbt-mainnet.gomaestro-api.org/v0 description: Bitcoin Mainnet - url: https://xbt-testnet.gomaestro-api.org/v0 description: Bitcoin Testnet security: - api-key: [] paths: /mempool/transactions/{tx_hash}/outputs/{output_index}: get: tags: - Transactions summary: Transaction Output Info (Mempool-aware) description: >- Provides detailed information for a single transaction output, including its value, spend status, and any attached metadata such as Ordinal inscriptions, Runes, or BRC20 data. In addition to confirmed transactions, mempool endpoints return data which reflects pending transactions in some number of "estimated" blocks - predicted blocks containing transactions which have been propagated around the network but not yet included in a mined block, with transactions with a higher sat/vB value being prioritised. The response details how many of these estimated blocks were considered when fetching the data. operationId: mempool_tx_output_info parameters: - name: tx_hash in: path description: Transaction hash required: true schema: type: string example: b077b8d829004197c5d71bbb755cf23914891db4768d642458c8ef245b3af7fe - name: output_index in: path description: Transaction output index required: true schema: type: string example: '0' responses: '200': description: Requested data content: application/json: schema: $ref: '#/components/schemas/MempoolTimestampedTxOutMetaprotocols' example: data: address: bc1qr46dacxy28zz5apsjrvs5jdgvs5sdcf2ed4tvl inscriptions: [] runes: [] satoshis: '85000' script_pubkey: 00141d74dee0c451c42a743090d90a49a8642906e12a spending_tx: null indexer_info: chain_tip: block_hash: >- 0000000000000000000085563bb7da463844c02d6c82bca13e3eec5411f8c8ed block_height: 897991 estimated_blocks: - block_height: 897992 sats_per_vb: max: 210 median: 4 min: 1 mempool_timestamp: '2025-05-23 11:43:08' '400': description: Malformed query parameters '404': description: Requested entity not found on-chain '500': description: Internal server error components: schemas: MempoolTimestampedTxOutMetaprotocols: type: object required: - data - indexer_info properties: data: $ref: '#/components/schemas/TxOutMetaprotocols' indexer_info: $ref: '#/components/schemas/MempoolLastUpdated' TxOutMetaprotocols: type: object required: - script_pubkey - satoshis - inscriptions - runes properties: address: type: string description: >- Address-encoding of the script pubkey at which the output containing the inscription resides. example: bc1ppth27qnr74qhusy9pmcyeaelgvsfky6qzquv9nf56gqmte59vfhqwkqguh nullable: true inscriptions: type: array items: $ref: '#/components/schemas/InscriptionAndOffset' description: List of inscription IDs and their offsets in this input. runes: type: array items: $ref: '#/components/schemas/RuneAndAmount' description: List of rune IDs and their amount in this input. satoshis: type: string description: Total number of satoshis in the UTxO. example: '1234567' script_pubkey: type: string description: >- Script pubkey at which the output containing the inscription resides. example: 51200aeeaf0263f5417e40850ef04cf73f43209b13401038c2cd34d201b5e685626e spending_tx: type: string description: >- If this output is known to have been spent, hash of the transaction that spent it. example: 2ca28d42583fc5bace84fe024d3697969e06dd1cf769a2141286825b81773fd5 nullable: true MempoolLastUpdated: type: object required: - chain_tip - estimated_blocks properties: chain_tip: $ref: '#/components/schemas/ChainTip' estimated_blocks: type: array items: $ref: '#/components/schemas/EstimatedBlock' description: >- Information about any estimated blocks from the mempool that were indexed in addition to the mainchain mempool_timestamp: type: string description: >- Timestamp of the indexed mempool snapshot, if any estimated blocks from the mempool have been indexed nullable: true InscriptionAndOffset: type: object required: - offset - inscription_id properties: inscription_id: type: string offset: type: integer format: int64 minimum: 0 RuneAndAmount: type: object required: - rune_id - amount properties: amount: type: string rune_id: type: string ChainTip: type: object required: - block_hash - block_height properties: block_hash: type: string description: The hash of the block example: 0000000000000000000a7f3b7b6b6e1d9a18db65a3b4a3f4f3bcb2e1f1b2d3e7 block_height: type: integer format: int64 description: The height of the block in the blockchain example: 707000 minimum: 0 EstimatedBlock: type: object required: - block_height - sats_per_vb properties: block_height: type: integer format: int64 description: Height of the estimated block example: '707001' minimum: 0 sats_per_vb: $ref: '#/components/schemas/BlockSatsPerVb' BlockSatsPerVb: type: object description: >- For transactions within a block, these are the lowest, median and highest satoshis per virtual-byte values. required: - min - median - max properties: max: type: integer format: int64 description: Highest sat/vB value of the transactions within the block example: 255 minimum: 0 median: type: integer format: int64 description: Median sat/vB value of the transactions within the block example: 15 minimum: 0 min: type: integer format: int64 description: Lowest sat/vB value of the transactions within the block example: 11 minimum: 0 securitySchemes: api-key: type: apiKey in: header name: api-key description: Project API Key ````