{"id":"7173fe0b-31d6-4cae-8641-725cec4b1f62","shortId":"9cuaEt","kind":"x402","title":"x402-gated API key endpoint on Base, paying $0.02 in USDC per request.","tagline":"x402-gated API key endpoint on Base, paying $0.02 in USDC per request.","description":"This endpoint at lowpaymentfee.com provides \"Premium API Access\" via the x402 payment protocol. It is one of many endpoints on the lowpaymentfee.com platform, which offers a broad catalog of pay-per-call APIs spanning data & analytics, AI & machine learning (sentiment analysis, text summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, settled in USDC on the Base network.\n\nThe specific endpoint `/api/v1/apikeys/21` is described only as \"Premium API Access\" with no further documentation on what it returns or what input it expects. The x402 challenge confirms it is live, accepts POST requests, and requires an exact payment of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. Payment is sent to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 with a 300-second timeout.\n\nDocumentation on the site is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a \"Connect wallet\" prompt with no additional content. There is no OpenAPI spec, no request/response schema, and no examples available. The purpose of this particular endpoint (API key generation? API key retrieval?) is unclear from the available material.","tags":[],"capabilities":["x402-payment","usdc-settlement","base-network","pay-per-request","api-key-access"],"categories":["infrastructure","api-management"],"synonyms":["premium API access","API key endpoint","x402 API","pay-per-call API","USDC API payment","lowpaymentfee","Base network API"],"warnings":["No documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no content.","The purpose of /api/v1/apikeys/21 is unclear: it could generate, retrieve, or validate an API key, but nothing specifies this.","No request or response schema is provided anywhere.","No OpenAPI or machine-readable spec found."],"endpointUrl":"https://lowpaymentfee.com/api/v1/apikeys/21","protocol":"x402","transport":"http","auth":{"type":"x402","details":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","extra":{"name":"USD Coin","version":"2"},"payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","scheme":"exact","network":"base","mimeType":"application/json","resource":"https://lowpaymentfee.com/api/v1/apikeys/21","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}]},"qualityScore":"0.300","qualityRationale":"The endpoint is live and returns a valid x402 challenge, but there is zero documentation on what this endpoint actually does, what inputs it accepts, or what it returns. No OpenAPI spec, no examples, and all doc pages are empty. The listing is effectively a stub.","verified":false,"liveness":"unknown","lastLivenessCheck":null,"agentReviews":{"count":0,"score_avg":null,"cost_usd_avg":null,"success_rate":null,"latency_p50_ms":null,"narrative_summary":null,"summary_updated_at":null},"enrichmentModel":"anthropic/claude-opus-4.6","enrichmentVersion":2,"enrichedAt":"2026-04-19T15:16:15.199Z","embedding":[-0.012039185,-0.031921387,0.03778076,0.0072402954,0.019012451,-0.039489746,-0.024154663,0.05368042,0.06222534,-0.074157715,0.021270752,-0.041503906,-0.04763794,-0.042938232,-0.026657104,0.0007586479,-0.031219482,0.0025367737,-0.06652832,0.019500732,0.03225708,-0.030334473,-0.0043029785,0.053222656,0.003107071,-0.016738892,-0.017028809,-0.015991211,-0.00095796585,-0.031204224,0.028121948,-0.026290894,-0.017059326,0.021438599,-0.026382446,0.0052719116,0.01108551,0.033294678,0.028533936,-0.008666992,-0.010604858,-0.06585693,-0.00008058548,0.008384705,-0.029144287,-0.004699707,0.0032978058,-0.029891968,-0.027572632,-0.008460999,-0.04034424,-0.002401352,-0.0154800415,-0.002483368,0.0010404587,0.009216309,-0.018417358,-0.029953003,0.0014305115,0.021606445,0.016708374,-0.05432129,-0.0038967133,0.012237549,0.013458252,0.053344727,-0.0063056946,0.054016113,0.013435364,0.042419434,0.042938232,0.047943115,0.024765015,0.014984131,-0.005657196,0.0126571655,-0.0035419464,0.058288574,-0.005458832,-0.017471313,-0.02192688,-0.0053863525,-0.048095703,-0.0074272156,-0.018875122,-0.06768799,-0.029190063,-0.0018978119,-0.015144348,0.021743774,-0.08258057,-0.017700195,-0.0063209534,0.0231781,0.013046265,0.0085372925,-0.025497437,0.015808105,-0.0158844,0.018417358,0.019699097,-0.03665161,0.024765015,0.02104187,0.043914795,0.045959473,0.002576828,0.02684021,0.009597778,-0.02885437,-0.035064697,-0.00409317,-0.019622803,-0.014465332,0.019958496,-0.008728027,-0.019897461,0.003068924,-0.017807007,0.013206482,-0.055145264,0.059020996,0.026870728,-0.017868042,0.010917664,-0.04940796,0.0024528503,0.0012788773,-0.023712158,-0.018310547,0.023071289,0.008369446,0.019470215,-0.0009794235,-0.042419434,0.013015747,-0.018966675,-0.022018433,-0.048736572,-0.011665344,0.028198242,-0.029922485,0.02734375,0.02619934,-0.10461426,-0.009544373,-0.05645752,0.007335663,-0.03125,-0.0181427,0.011001587,0.010231018,-0.0012836456,-0.017684937,-0.004096985,-0.01020813,-0.010238647,0.026031494,-0.010887146,0.043151855,-0.0058059692,0.04309082,0.03387451,0.02619934,0.022460938,0.047607422,0.013214111,-0.078308105,-0.07476807,-0.025924683,-0.016906738,-0.009971619,-0.03665161,0.024215698,-0.014320374,-0.072509766,-0.029067993,-0.0032463074,-0.01322937,-0.035308838,-0.010307312,-0.024383545,0.0024776459,-0.007003784,-0.05593872,-0.017410278,-0.017028809,0.060577393,0.015258789,-0.0064201355,0.03302002,-0.003419876,0.05822754,0.006252289,-0.009483337,-0.04107666,0.012298584,-0.02659607,0.048187256,0.010559082,0.004135132,-0.036010742,0.023712158,0.04788208,0.032592773,-0.01399231,0.019851685,-0.048797607,-0.033294678,-0.0335083,-0.0012674332,-0.0011520386,0.0030498505,0.027267456,-0.028198242,-0.012718201,-0.003622055,0.012550354,0.020370483,0.064819336,-0.018051147,-0.0051574707,0.012840271,0.03540039,-0.032043457,0.043548584,0.02760315,0.021057129,-0.03111267,-0.024002075,0.028274536,0.049468994,-0.02418518,-0.00308609,-0.018234253,0.012664795,-0.007858276,0.0072669983,0.022842407,-0.006259918,-0.017074585,-0.03829956,-0.02432251,0.030334473,-0.009407043,-0.022399902,-0.05404663,-0.0637207,0.039611816,0.033966064,0.022277832,-0.0004451275,0.011672974,-0.015289307,-0.005519867,-0.061157227,0.041168213,0.07623291,-0.018417358,-0.016677856,0.022613525,-0.020950317,-0.030593872,-0.013931274,-0.0029621124,-0.033294678,-0.02571106,0.018707275,-0.042175293,0.009750366,0.01979065,0.024871826,0.053527832,-0.019622803,-0.027313232,-0.027755737,-0.0006275177,0.008346558,-0.047943115,-0.018310547,0.0077667236,0.016036987,0.044006348,-0.01448822,0.02217102,-0.0012226105,0.010116577,-0.0134887695,-0.021408081,-0.030471802,-0.019973755,0.026657104,0.012046814,-0.06008911,0.016296387,-0.0031318665,0.04421997,-0.03955078,0.02923584,-0.012924194,0.016326904,0.035064697,-0.023620605,-0.0524292,-0.011978149,0.0256958,0.042907715,0.04336548,0.021133423,-0.00066423416,0.0042304993,0.05859375,-0.026748657,-0.01701355,-0.001458168,0.021209717,0.03466797,-0.014923096,-0.064453125,-0.03918457,-0.026306152,-0.033569336,0.01914978,-0.029373169,0.024993896,-0.0037117004,-0.0067749023,-0.017852783,0.0031375885,-0.029296875,0.026153564,-0.034973145,0.015426636,-0.017990112,-0.023391724,0.0037670135,0.033599854,-0.0053520203,0.006126404,0.039001465,0.009895325,-0.013061523,-0.02229309,-0.010955811,-0.018096924,0.013145447,0.03881836,0.017410278,0.015472412,0.040496826,-0.026412964,0.021469116,0.02960205,0.0052337646,0.03111267,-0.013015747,0.0032291412,-0.057037354,-0.061676025,-0.014152527,-0.03463745,0.023223877,0.0019159317,-0.00066137314,0.049041748,-0.01676941,-0.0047416687,-0.050842285,0.028305054,-0.02406311,-0.0070228577,0.04119873,-0.016220093,-0.04473877,-0.0005173683,0.007335663,0.009712219,0.035003662,0.01638794,0.012382507,0.07159424,0.042816162,0.0075645447,0.00023519993,0.02381897,0.017623901,-0.011962891,-0.02293396,-0.025390625,0.012123108,0.0129776,-0.025634766,-0.022247314,-0.06896973,0.07733154,0.041748047,0.06781006,0.0069389343,0.008377075,0.040863037,-0.02079773,0.0055007935,-0.018341064,-0.00969696,-0.020355225,-0.049041748,0.018157959,-0.012145996,0.0075798035,-0.028640747,0.027130127,0.019485474,0.009010315,-0.0637207,0.05697632,0.0102005005,0.0022201538,0.016036987,0.0036754608,0.037994385,0.038513184,-0.046936035,0.007972717,0.009002686,-0.02709961,-0.0040512085,0.03842163,-0.0026245117,-0.015609741,-0.06707764,-0.021942139,-0.0022392273,-0.022613525,-0.072753906,-0.013504028,0.015235901,0.01776123,0.02960205,-0.03744507,-0.037597656,0.0029277802,-0.02368164,-0.05895996,0.0018177032,-0.059387207,0.02684021,0.03744507,-0.030410767,-0.011421204,0.014305115,-0.005256653,-0.0154418945,0.025817871,0.00920105,0.0070648193,-0.048828125,0.02079773,0.006210327,0.0026397705,0.023223877,0.014389038,0.027008057,0.015777588,0.042236328,0.010826111,-0.015052795,-0.051879883,0.027160645,-0.05279541,0.009902954,-0.00020241737,-0.03201294,-0.011169434,-0.0013980865,-0.029144287,-0.023254395,0.0039634705,-0.03048706,0.021987915,0.044311523,-0.052246094,-0.02268982,-0.05053711,-0.01739502,0.007610321,0.07287598,0.041168213,0.0047416687,-0.058746338,-0.024383545,0.017730713,0.0040245056,-0.0008339882,-0.014518738,-0.0102005005,-0.01398468,-0.017730713,-0.030807495,-0.024230957,0.042755127,-0.015350342,-0.001572609,0.021469116,0.01826477,0.00023150444,0.014846802,0.010910034,0.026184082,-0.034942627,0.0008869171,-0.020767212,0.014778137,-0.004486084,-0.02204895,-0.045654297,0.044189453,0.009597778,0.039916992,-0.035461426,0.0022888184,0.0027065277,0.023345947,0.0104599,-0.0013256073,-0.0059127808,0.007041931,-0.051086426,-0.07122803,0.02468872,-0.02027893,0.0335083,0.015335083,0.010360718,0.035461426,-0.0047798157,-0.0069274902,0.038635254,-0.02406311,-0.011497498,-0.037078857,-0.03353882,-0.0054359436,0.022399902,-0.022491455,0.010047913,-0.010559082,0.009841919,-0.009757996,-0.023651123,0.022750854,0.013168335,0.00011241436,0.013748169,0.0033187866,0.014854431,0.0541687,0.006401062,-0.027008057,0.020324707,0.008514404,0.0053253174,-0.0030517578,0.038482666,0.025726318,-0.033935547,-0.0024528503,-0.00086402893,0.0007753372,-0.0146484375,-0.020828247,0.008010864,0.025512695,-0.002773285,-0.037322998,0.027130127,0.029296875,-0.018997192,-0.013412476,0.020339966,0.032806396,-0.034973145,0.020431519,0.016159058,0.060150146,-0.012252808,-0.007835388,0.007637024,0.028640747,0.0074920654,0.010269165,-0.014152527,0.012840271,-0.024093628,0.009086609,-0.004096985,0.00724411,0.01675415,-0.014022827,0.004776001,0.023468018,0.011138916,-0.0069847107,-0.037353516,0.0005507469,-0.007637024,-0.0058250427,0.011787415,0.022598267,0.022094727,-0.028900146,0.01701355,0.018600464,-0.029083252,-0.02218628,-0.005832672,0.04168701,-0.006881714,0.0020103455,0.009391785,0.008125305,0.026611328,-0.05807495,0.0014390945,0.01878357,0.022628784,-0.01889038,-0.0625,-0.037261963,-0.017105103,0.057037354,0.0005159378,0.012611389,0.021255493,0.005836487,-0.010810852,0.01424408,0.0040740967,-0.012863159,-0.02116394,-0.034454346,-0.013549805,0.0025787354,-0.00070619583,-0.016845703,0.014099121,-0.013412476,-0.02973938,0.016693115,-0.010673523,-0.010559082,-0.0077781677,0.014579773,0.031463623,0.003955841,0.019088745,-0.018066406,-0.023666382,0.009277344,0.014060974,0.01210022,-0.046875,0.02218628,-0.02519226,-0.013504028,-0.0033683777,0.0073547363,0.012374878,0.014221191,-0.0031547546,0.032287598,-0.061401367,0.038482666,-0.056884766,0.008934021,-0.0051002502,-0.02609253,-0.005554199,-0.03778076,-0.02406311,0.025878906,-0.01184082,-0.0045051575,-0.031143188,-0.025497437,-0.0022563934,-0.04901123,0.027267456,0.033050537,0.0340271,-0.040802002,0.0023040771,-0.0037460327,-0.0020828247,-0.0046310425,-0.0016126633,-0.0031414032,0.020980835,0.024642944,-0.005645752,-0.033569336,-0.02658081,-0.0054130554,-0.016830444,-0.03439331,-0.055786133,-0.00793457,0.025405884,0.001991272,0.00844574,-0.041107178,-0.018157959,-0.00052022934,-0.041992188,0.013114929,-0.0020332336,0.0042762756,0.009246826,-0.010818481,0.012329102,0.034576416,-0.031173706,0.044006348,0.0066375732,-0.008834839,-0.040039062,-0.0014009476,0.045562744,0.010139465,0.0006594658,-0.0034008026,-0.009002686,-0.025512695,-0.038635254,-0.018798828,-0.005748749,-0.0043640137,0.0038280487,0.003534317,-0.04776001,-0.019439697,-0.025527954,-0.0070648193,0.02003479,0.043273926,0.013641357,-0.0039253235,0.010955811,-0.0077209473,-0.011489868,-0.039367676,0.014671326,0.010559082,-0.008094788,0.026138306,0.046325684,0.02444458,-0.00014269352,0.0045204163,-0.00019145012,0.019989014,-0.016433716,0.009605408,-0.026794434,0.0053901672,0.00049209595,-0.014297485,-0.024780273,-0.0018358231,0.07550049,0.005054474,0.004234314,-0.0037078857,-0.01777649,0.02166748,0.021743774,-0.0748291,-0.010444641,-0.028900146,0.011734009,-0.007534027,0.02279663,0.0034503937,0.0020217896,-0.019042969,-0.046661377,-0.0061035156,0.008239746,0.0040512085,-0.07165527,-0.016052246,-0.035949707,-0.018051147,-0.0053253174,-0.011329651,0.001364708,0.0046539307,-0.019317627,-0.08355713,0.006298065,0.04953003,0.015388489,0.009864807,-0.02168274,-0.00012636185,0.015403748,-0.031707764,-0.022949219,0.029159546,-0.021865845,-0.016647339,-0.02798462,0.04421997,-0.025283813,-0.021453857,0.023361206,-0.004398346,0.042755127,-0.012809753,0.011512756,-0.00022029877,0.0035552979,-0.01751709,-0.0019283295,-0.0018815994,-0.01448822,0.02130127,-0.048431396,0.023284912,0.022201538,0.015014648,-0.00020682812,0.025375366,0.03427124,-0.044708252,-0.0019397736,0.039611816,-0.008552551,0.031204224,-0.03326416,0.048461914,0.012260437,-0.0046844482,0.022399902,-0.012878418,-0.02633667,-0.052947998,-0.026687622,0.025222778,0.017547607,0.021835327,-0.01940918,-0.0010843277,0.0368042,-0.0013303757,0.005695343,-0.025222778,-0.020431519,-0.03048706,0.0015764236,0.0068740845,-0.0003578663,-0.0050201416,0.026382446,0.03189087,0.039031982,-0.006263733,-0.01751709,0.018249512,0.012786865,-0.011764526,0.0008149147,0.019424438,0.01902771,0.01763916,0.023452759,0.013801575,-0.02986145,-0.014762878,-0.031341553,-0.003856659,0.0143585205,-0.0076828003,-0.008140564,-0.009178162,-0.00027894974,0.0093688965,-0.03479004,0.020339966,-0.04925537,-0.023147583,-0.0059051514,-0.013618469,0.011199951,0.018173218,0.01309967,0.018371582,0.007369995,0.06161499,0.012832642,-0.0047454834,0.02607727,0.044708252,0.0181427,-0.019226074,-0.013969421,-0.012168884,0.008728027,0.0020866394,-0.021148682,0.020614624,0.034729004,-0.028961182,0.017456055,0.00868988,0.015403748,-0.020370483,0.008102417,-0.0001872778,0.022155762,-0.01977539,0.028671265,-0.042419434,0.00566864,0.022781372,-0.0011405945,0.004005432,-0.031143188,-0.030288696,0.0017251968,0.0040512085,-0.033813477,0.050201416,-0.009933472,0.01638794,-0.024169922,-0.025909424,0.0038108826,-0.03753662,-0.02267456,0.025100708,-0.013374329,-0.015129089,0.015403748,-0.021591187,0.028152466,-0.035339355,-0.0034694672,0.00869751,-0.0077667236,-0.022949219,-0.0022602081,-0.022979736,-0.0055885315,-0.004890442,-0.011192322,-0.006752014,0.0496521,0.04043579,0.021591187,0.037963867,0.0088272095,0.008674622,-0.038146973,-0.02267456,0.0007786751,-0.01902771,0.0103302,-0.010566711,0.056396484,0.036987305,0.0054855347,0.035583496,0.032348633,0.020095825,-0.0003707409,0.0052833557,-0.0061912537,0.02520752,-0.00712204,0.025497437,-0.0006580353,0.033172607,-0.039733887,0.0115356445,0.0011882782,0.026321411,-0.03744507,0.037078857,0.07318115,0.028015137,-0.015014648,0.04006958,-0.0036678314,-0.008834839,-0.025009155,-0.016952515,0.051879883,0.017654419,0.038848877,0.03765869,0.008674622,-0.0033454895,0.0073242188,-0.021743774,-0.029266357,0.06732178,0.019210815,-0.029067993,-0.011138916,-0.015586853,0.0073509216,-0.050628662,-0.029418945,0.0027980804,-0.005760193,0.0038471222,-0.01725769,-0.0005874634,-0.023086548,0.015930176,0.009559631,0.010253906,-0.019958496,0.039733887,0.006893158,0.010292053,0.026412964,-0.0027332306,0.03302002,-0.029159546,-0.022109985,0.009613037,0.027236938,0.006790161,-0.019546509,0.01727295,0.015220642,0.06585693,0.039398193,-0.007621765,0.006290436,0.025131226,0.013214111,0.001405716,0.050933838,0.021438599,0.01235199,0.025299072,0.035095215,0.018310547,-0.035064697,0.007850647,0.0012264252,0.004928589,-0.014945984,-0.018798828,-0.000518322,-0.019454956,0.018066406,0.0012578964,-0.017929077,0.033111572,0.03036499,0.008636475,0.008277893,-0.006298065,0.011917114,-0.00079870224,0.008834839,0.01953125,-0.00806427,0.02923584,0.012687683,0.017684937,-0.032318115,0.0368042,-0.0019989014,-0.016296387,-0.012908936,0.010055542,-0.04321289,-0.0009832382,-0.005214691,-0.011047363,-0.030776978,0.015792847,0.01751709,0.0061798096,0.033599854,0.018508911,0.002664566,-0.00299263,0.013656616,0.01739502,-0.010528564,-0.011230469,-0.024139404,0.012672424,0.027633667,-0.0034637451,0.01826477,-0.024597168,0.0044670105,0.007785797,-0.018157959,0.0024204254,-0.0029792786,-0.017440796,-0.03213501,0.013092041,0.048980713,0.014083862,0.031143188,-0.00844574,-0.019989014,0.010620117,0.01461792,0.011405945,0.010772705,-0.020645142,0.029769897,0.0017623901,0.050231934,0.037353516,0.008056641,0.026184082,-0.026977539,-0.01789856,0.0074882507,-0.013542175,0.0135269165,-0.013893127,0.020080566,-0.01209259,0.032073975,-0.026641846,-0.032287598,0.003616333,-0.016448975,-0.0143585205,-0.02609253,0.0053710938,0.008483887,0.017364502,0.040405273,0.021331787,-0.023971558,0.06732178,-0.01309967,0.054382324,-0.025756836,-0.010475159,0.039001465,0.039276123,0.025787354,0.010307312,0.008033752,-0.01852417,0.01739502,0.058685303,0.036499023,0.0012798309,0.0039138794,-0.022872925,0.022018433,0.0014066696,0.022903442,-0.0017662048,-0.013771057,0.008773804,-0.009529114,-0.03387451,0.010177612,-0.012062073,0.0124435425,0.037231445,-0.040985107,-0.020202637,-0.015350342,-0.026275635,0.02168274,-0.0067749023,0.013710022,-0.011184692,-0.025665283,0.0008568764,-0.024505615,-0.0058135986,-0.012031555,0.039978027,-0.045898438,-0.01687622,-0.006755829,0.03152466,-0.02003479,0.01979065,0.039093018,-0.020935059,0.0054512024,0.04776001,-0.0019798279,0.047607422,-0.013595581,0.017684937,0.05053711,0.0068206787,-0.0075263977,0.016830444,0.0069465637,-0.02432251,0.009727478,0.045928955,-0.008811951,0.009552002,0.010734558,-0.014450073,0.007129669,0.0026054382,0.0034313202,-0.008201599,-0.007019043,-0.006565094,-0.0071105957,0.025985718,0.0039978027,-0.009094238,-0.0022773743,-0.017364502,0.011299133,0.026504517,0.0007047653,-0.035369873,-0.008964539,0.014961243,0.016967773,-0.0085372925,-0.014259338,-0.019866943,-0.039276123,0.020462036,0.03479004,0.00881958,0.00094795227,-0.03186035,0.0013017654,0.019226074,0.014701843,0.0052108765,0.00818634,-0.008735657,-0.00017535686,-0.01914978,-0.012565613,-0.01828003,-0.0064849854,0.010215759,0.043823242,-0.00043177605,-0.022338867,0.008613586,0.0020446777,0.014221191,0.0022277832,-0.014335632,0.025115967,-0.014518738,-0.014816284,-0.003824234,0.010070801,-0.028335571,-0.02067566,-0.01637268,0.014778137,0.04208374,-0.010154724,-0.020248413,0.0071144104,0.012359619,0.019424438,0.029266357,0.008460999,0.050109863,0.025558472,-0.0077781677,-0.019958496,0.0048675537,-0.01612854,-0.023620605,0.008056641,-0.0104599,-0.025802612,0.03237915,0.0063095093,-0.0055503845,-0.029067993,-0.01008606,-0.00032281876,-0.011894226,0.024627686,-0.01234436,0.009933472,-0.031219482,-0.0009675026,-0.0014801025,-0.00026845932,-0.034362793,-0.023773193,-0.00016117096,-0.0073051453,-0.04812622,0.007396698,-0.033599854,0.00806427,-0.013908386,-0.004470825,0.0002706051,0.03326416,-0.007129669,0.011306763,0.015167236,0.026123047,0.010757446,0.025405884,0.031677246,-0.020126343,-0.028274536,-0.01876831,0.012519836,-0.017440796,0.03152466,-0.011459351,0.034576416,0.008285522,-0.01210022,-0.0008893013,-0.0068740845,-0.0146865845,-0.0018815994,-0.01398468,-0.011169434,0.016021729,0.0231781,-0.0077934265,-0.008773804,0.041625977,-0.018249512,-0.0022010803,0.023635864,0.053741455,0.0028514862,0.044067383,-0.0004925728,-0.002904892,-0.017578125,0.0025157928,-0.028640747,0.017440796,0.013313293,0.007736206,-0.0054244995,-0.0014772415,0.0076904297,-0.014350891,0.010063171,0.021026611,0.0050354004,-0.0146102905,0.024246216,0.00289917,0.006538391,-0.021514893,-0.015556335,0.0143966675,0.033294678,0.016677856,-0.0004439354,0.0014533997,0.010070801,-0.011581421,0.0073890686,0.01499939,-0.024612427,-0.028198242,-0.023132324,-0.036987305,0.019546509,0.015930176,0.016357422,0.00052022934,0.015167236,-0.008132935,-0.037872314,-0.012817383,0.023803711,0.0048217773,-0.0065231323,-0.012283325,0.0015668869,0.009429932,-0.024612427,0.004096985,-0.045410156,-0.020965576,-0.0075263977,-0.018234253,0.008239746,0.00028657913,-0.011779785,0.012199402,-0.012329102,0.002483368,0.015716553,0.019866943,-0.008117676,-0.0005583763,-0.0013141632,0.010658264,-0.013267517,0.011695862,-0.011184692,0.0000073313713,0.032714844,-0.0054779053,0.016555786,-0.0067367554,0.02267456,0.0046195984,-0.008094788,0.03378296,0.0038604736,0.013473511,-0.027450562,0.0030078888,0.00019979477,-0.009101868,0.023788452,-0.018234253,-0.02508545,0.0082473755,-0.016830444,-0.04095459,-0.004966736,0.040618896,0.042053223,-0.018829346,0.032196045,-0.014984131,-0.0045166016,0.006111145,-0.00025987625,-0.014541626,-0.004043579,0.05331421,-0.0006313324,-0.0047187805,-0.0053100586,0.006298065,-0.02947998,-0.024169922,0.01927185,-0.0044021606,-0.0053253174,0.012641907,0.0038452148,0.03137207,-0.0019235611,0.011306763,0.011695862,0.0037231445,0.022201538,0.0073623657,0.050445557,-0.010627747,-0.024917603,0.00868988,0.026763916,-0.017318726,-0.0067977905,-0.0038604736,-0.0032291412,-0.043151855,0.02458191,-0.0135650635,0.022323608,-0.025878906,0.008995056,-0.01876831,-0.018432617,-0.025009155,-0.0054969788,-0.03479004,-0.004776001,0.04260254,0.014709473,0.005256653,-0.000374794,-0.03515625,0.042633057,0.047912598,-0.0033302307,-0.021377563,-0.014152527,0.009513855,-0.01411438,0.0021591187,0.011711121,-0.032714844,-0.025939941,-0.0013084412,-0.014038086,0.007232666,-0.006752014,0.014556885,0.0014743805,-0.007888794,0.0076675415,0.023376465,0.001953125,-0.005077362,0.005050659,0.0017280579,0.04647827,0.027526855,-0.009979248,0.018630981,0.017181396,-0.030227661,0.05645752,-0.024414062,0.019210815,-0.01902771,0.0028648376,-0.040130615,-0.01727295,-0.006149292,0.0018606186],"createdAt":"2026-04-18T19:29:30.215Z","updatedAt":"2026-04-23T08:02:07.726Z","lastSeenAt":"2026-04-23T08:02:07.726Z","tsv":"'/api':185 '/api/v1/apikeys/21':110 '/docs':184 '/pricing':186 '/readme':188 '0.02':10,24,97,159 '000':148 '0x1a2b13e97f5f837c8f9fa1f95a1484b7c70d85f3':170 '0x8335':153 '20':147 '2913':154 '300':173 '6':163 'API key endpoint' 'Base network API' 'USDC API payment' 'accept':138 'access':36,117 'addit':199 'address':169 'ai':66 'analysi':70 'analyt':65 'api':4,18,35,62,116,219,222 'api-key-access' 'avail':212,229 'base':8,22,105,149,156 'base-network' 'broad':55 'call':61 'catalog':56 'challeng':133 'classif':73 'confirm':134 'connect':194 'content':200 'convers':90 'data':64 'decim':164 'describ':112 'document':121,176 'embed':74 'endpoint':6,20,30,47,93,109,218 'equal':158 'estim':84 'exact':144 'exampl':211 'exchang':79 'expect':130 'extrem':181 'feed':78 'financ':75 'gas':83 'gate':3,17 'generat':91,221 'geocod':88 'given':160 'infrastructur':86 'input':128 'key':5,19,220,223 'learn':68 'live':137 'lowpaymentfee' 'lowpaymentfee.com':32,50 'machin':67 'mani':46 'materi':230 'network':106 'offer':53 'one':44 'openapi':204 'page':189 'particular':217 'pay':9,23,59 'pay-per-cal':58 'pay-per-call API' 'pay-per-request' 'payment':40,145,165 'per':13,27,60,98 'platform':51 'post':139 'premium':34,115 'premium API access' 'price':77,95 'prompt':196 'protocol':41 'provid':33 'purpos':214 'quot':82 'rate':80 'render':191 'request':14,28,99,140 'request/response':207 'requir':142 'retriev':224 'return':125 'schema':208 'second':174 'sent':167 'sentiment':69 'settl':100 'site':179 'span':63 'spars':182 'spec':205 'specif':108 'summar':72 'text':71 'timeout':175 'token':81 'unclear':226 'unit':150 'usdc':12,26,102,152,161 'usdc-settlement' 'util':87 'valid':89 'via':37 'wallet':195 'web3':76 'x402':2,16,39,132 'x402 API' 'x402-gated':1,15 'x402-payment'","prices":[{"id":"95bd11d2-a0c8-4286-b501-6afb49b46c3e","listingId":"7173fe0b-31d6-4cae-8641-725cec4b1f62","amountUsd":null,"unit":"per_call","nativeCurrency":"USD COIN","nativeAmount":"20000","chain":"base","payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","paymentMethod":"x402-usd coin","isPrimary":true,"details":{"scheme":"exact","mime_type":"application/json","accepts_all":[{"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","extra":{"name":"USD Coin","version":"2"},"payTo":"0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3","scheme":"exact","network":"base","mimeType":"application/json","resource":"https://lowpaymentfee.com/api/v1/apikeys/21","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-18T19:29:30.215Z"}],"sources":[{"listingId":"7173fe0b-31d6-4cae-8641-725cec4b1f62","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/apikeys/21","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-18T19:29:30.215Z","lastSeenAt":"2026-04-23T08:02:07.726Z"}],"details":{"listingId":"7173fe0b-31d6-4cae-8641-725cec4b1f62","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/apikeys/21 \\\n  -H \"X-PAYMENT: <x402-payment-token>\" \\\n  -H \"Content-Type: application/json\"","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/apikeys/21"},{"claim":"All endpoints on the platform are priced at $0.02 per request with no minimums or commitments","source_url":"https://lowpaymentfee.com"},{"claim":"The platform offers APIs across data & analytics, AI & ML, finance & Web3, and infrastructure categories","source_url":"https://lowpaymentfee.com"},{"claim":"USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base network","source_url":"https://lowpaymentfee.com/api/v1/apikeys/21"}],"useCases":["Purchasing or retrieving an API key via a single micropayment","Agent-driven access to gated API resources without pre-registration","Programmatic pay-per-use API key provisioning"],"bestFor":["Agents needing instant API access without signup or subscriptions","Developers experimenting with x402 payment-gated endpoints","Micropayment-based API consumption on Base"],"notFor":["Users who need detailed API documentation or schemas before purchasing","High-volume use cases where per-request pricing may add up","Anyone requiring non-crypto payment methods"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:29.147Z"},"updatedAt":"2026-04-23T08:02:07.726Z"}}