{"id":"ecc577bb-a838-44cc-989a-9bbd19376fe9","shortId":"vDgPpn","kind":"x402","title":"Retrieve email attachments via x402 micropayment on Base for $0.02 per request.","tagline":"Retrieve email attachments via x402 micropayment on Base for $0.02 per request.","description":"This endpoint at lowpaymentfee.com provides access to email attachments (specifically for email ID 50) behind an x402 paywall. The endpoint accepts POST requests and returns JSON. Payment is settled in USDC on the Base network at $0.02 per call (maxAmountRequired of 20,000 base units with 6 decimals = $0.02), with no API keys, rate limits, or subscriptions required.\n\nThe provider lowpaymentfee.com hosts a broader suite of x402-gated APIs spanning data analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance/crypto market data, and infrastructure utilities — all priced at $0.02 per request. However, this specific listing covers only the `/api/v1/emails/50/attachments` endpoint. Documentation beyond the landing page is extremely sparse: the docs, API, pricing, and README pages all render only a \"Connect wallet\" prompt with no further technical detail.\n\nBecause there is no OpenAPI schema, no request/response examples, and no documentation describing what fields to send or what the response looks like, the actual behavior of this endpoint is largely unknown. The endpoint is confirmed live (returns a valid x402 402 challenge), but callers will need to experiment to discover the expected request body and response format.","tags":[],"capabilities":["x402-payment","usdc-base","email-attachments","micropayment","no-api-key","pay-per-request"],"categories":["email","storage"],"synonyms":["email attachment API","x402 email endpoint","pay-per-call email","Base USDC API","micropayment email attachments","lowpaymentfee email"],"warnings":["No API documentation available — docs, pricing, and README pages are empty","No request or response schema provided; callers must discover the interface experimentally","Endpoint path is hardcoded to email ID 50; unclear if other email IDs are supported","Provider site offers many endpoints but none have documented schemas"],"endpointUrl":"https://lowpaymentfee.com/api/v1/emails/50/attachments","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/emails/50/attachments","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 402 challenge, confirming it exists and accepts USDC on Base. However, there is no OpenAPI schema, no request/response examples, and no meaningful documentation — the docs/pricing/README pages are all blank beyond a wallet connect prompt. The endpoint path suggests a hardcoded email ID (50), which raises questions about generality. Effectively a stub listing.","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":"2026-04-21T19:16:47.872Z","embedding":[-0.03729248,-0.0047912598,0.04638672,0.018249512,-0.0021972656,-0.059295654,-0.02619934,0.041900635,0.06652832,-0.0703125,0.026473999,-0.040740967,-0.020629883,-0.030975342,-0.042541504,0.006160736,0.017852783,-0.037261963,-0.034484863,0.028030396,0.046783447,-0.020004272,-0.023025513,0.0077056885,-0.012825012,-0.0107421875,-0.011207581,0.0054779053,-0.003227234,-0.04916382,0.020202637,-0.023590088,-0.01826477,0.007785797,-0.034729004,0.050750732,-0.017471313,0.033721924,0.024230957,0.0029754639,0.018478394,-0.020248413,0.010292053,0.013885498,-0.039764404,-0.0047035217,0.020858765,-0.043518066,0.013877869,-0.007873535,-0.012969971,0.013420105,0.005607605,0.010681152,0.023468018,0.03475952,0.012413025,0.0008664131,-0.01121521,0.035980225,-0.017929077,-0.06939697,-0.020721436,-0.008148193,0.000538826,0.046813965,-0.020263672,0.04006958,0.019500732,0.08532715,0.029052734,0.054626465,0.054229736,0.010757446,0.007736206,-0.027038574,-0.0030708313,0.01940918,-0.034332275,-0.03540039,-0.004737854,-0.021377563,-0.04458618,0.009155273,-0.048980713,-0.041381836,-0.007873535,0.023788452,-0.03262329,0.03781128,-0.09777832,0.0079574585,-0.0044822693,-0.005458832,0.0033283234,-0.0076408386,-0.021255493,0.009300232,0.006000519,0.006855011,0.010803223,-0.033691406,0.008377075,-0.020874023,0.042419434,0.028869629,0.015357971,0.020095825,0.016738892,0.008201599,-0.022644043,-0.007396698,-0.013885498,-0.0033340454,0.02708435,-0.005886078,-0.03338623,0.04196167,-0.030975342,0.01902771,-0.03805542,0.052886963,0.016784668,-0.006038666,0.011314392,-0.037750244,-0.022338867,0.023452759,-0.034698486,0.008346558,0.068237305,0.023635864,0.05331421,-0.035369873,-0.027069092,0.013404846,-0.00034856796,-0.012886047,-0.048828125,-0.027755737,0.046966553,-0.029800415,0.015136719,0.0063972473,-0.0871582,0.0057144165,-0.03994751,0.00466156,-0.00182724,-0.009552002,0.019927979,-0.008781433,0.0039901733,-0.0068626404,-0.025924683,-0.031585693,-0.0028839111,0.024261475,-0.008712769,0.019332886,-0.016448975,0.0036792755,0.016677856,-0.019226074,0.011619568,0.043945312,0.014793396,-0.059295654,-0.06768799,-0.02772522,0.0060195923,-0.013954163,-0.023483276,0.019180298,-0.008834839,-0.068603516,0.007698059,-0.009727478,0.004207611,-0.038360596,0.0019664764,-0.03604126,-0.0020828247,-0.000029146671,-0.06274414,-0.0181427,-0.0143585205,0.07525635,0.0019893646,0.015563965,0.035339355,-0.011123657,0.034942627,0.025741577,-0.01776123,-0.018859863,0.016677856,-0.015525818,0.035064697,0.014389038,-0.006668091,-0.020980835,0.03665161,0.05545044,-0.003118515,-0.00020313263,0.0029449463,-0.010017395,-0.016220093,-0.019958496,0.021759033,0.0012750626,-0.0020503998,0.027770996,-0.031799316,-0.032409668,0.012046814,0.009506226,0.018478394,0.058258057,-0.0062217712,0.015411377,0.030914307,0.02571106,-0.03665161,0.036010742,0.014503479,0.0074806213,-0.006587982,-0.03338623,0.01776123,0.027832031,-0.026855469,0.018157959,-0.019958496,0.030273438,-0.01272583,-0.009155273,0.022537231,-0.009994507,-0.017715454,-0.03274536,0.009979248,0.019332886,-0.011489868,-0.043762207,-0.045654297,-0.048034668,0.06707764,0.015129089,0.029800415,0.006126404,-0.020339966,-0.023422241,-0.012626648,-0.06100464,0.02557373,0.06536865,0.0073127747,-0.012588501,0.043395996,-0.008056641,-0.05718994,0.0079574585,0.0149002075,-0.025314331,-0.015548706,0.012214661,-0.051239014,0.03201294,0.0022602081,0.053863525,0.05279541,-0.003932953,-0.045196533,0.0037784576,-0.023590088,-0.023452759,-0.018707275,0.006259918,-0.013389587,-0.000050365925,0.016036987,-0.030410767,0.02619934,0.004760742,0.015205383,0.0029563904,0.0234375,-0.038909912,-0.021270752,-0.0010519028,0.02684021,-0.053527832,-0.0007519722,-0.006629944,0.05041504,-0.05239868,0.045318604,-0.030258179,0.003921509,0.058685303,0.013069153,-0.058044434,0.002784729,0.007911682,0.013069153,0.05621338,-0.008354187,0.0034122467,-0.013221741,0.04598999,-0.050689697,0.008094788,0.01651001,0.030838013,0.014007568,0.029418945,-0.03604126,-0.030273438,-0.0037555695,-0.005607605,0.028335571,-0.033843994,0.04788208,-0.0019435883,0.013259888,-0.027877808,-0.01335144,-0.015823364,-0.005443573,-0.021438599,0.00019049644,-0.032592773,-0.014297485,0.026031494,0.01146698,-0.00598526,0.0010375977,0.054382324,-0.00090646744,0.0019989014,-0.019241333,-0.028244019,-0.045074463,-0.039001465,0.002368927,0.013618469,0.011566162,0.020080566,-0.029541016,0.0023975372,0.027694702,0.01259613,0.015716553,0.006996155,0.016036987,-0.099853516,-0.023773193,-0.030899048,-0.028701782,0.021514893,0.03237915,0.012207031,0.070129395,0.002916336,-0.029159546,-0.06085205,0.027191162,-0.04623413,0.016235352,0.046783447,-0.016052246,-0.008560181,-0.008468628,-0.007873535,0.011238098,0.053710938,0.014167786,0.029251099,0.062286377,0.050567627,-0.0077438354,0.0015630722,0.016799927,-0.00017976761,-0.021652222,-0.009849548,-0.02935791,-0.018325806,0.02772522,-0.003452301,-0.02999878,-0.051116943,0.04852295,0.06756592,0.07318115,0.025390625,0.015586853,-0.005256653,-0.031707764,0.0043792725,-0.024032593,-0.019195557,-0.021560669,-0.044189453,0.013221741,-0.009170532,0.026473999,-0.034332275,0.008850098,-0.0022449493,0.007965088,-0.0043411255,0.06213379,0.0012454987,-0.0019407272,0.029434204,0.028625488,0.031402588,0.01878357,-0.03265381,0.032043457,0.03918457,-0.021133423,-0.00868988,0.033111572,-0.014526367,-0.0016593933,-0.050750732,-0.048614502,-0.011428833,-0.054779053,-0.060394287,0.0043296814,-0.017791748,0.044158936,0.052856445,-0.021728516,-0.04586792,0.0132751465,-0.015052795,-0.057281494,0.008132935,-0.045776367,0.01574707,0.012481689,-0.01651001,0.014434814,0.010025024,-0.011405945,-0.0071029663,0.03414917,-0.014640808,0.015670776,-0.03274536,0.00762558,-0.028518677,0.018249512,0.014579773,0.024963379,0.018066406,0.02935791,0.01373291,-0.0011177063,-0.023269653,-0.066467285,0.018951416,-0.044921875,0.024993896,0.044403076,-0.011245728,-0.0010900497,-0.0014266968,-0.018249512,-0.0368042,0.026809692,-0.05331421,-0.015655518,0.005622864,-0.022857666,-0.028015137,-0.053771973,-0.044128418,-0.03845215,0.060760498,0.031433105,0.012138367,-0.01737976,-0.024597168,0.019683838,0.00091171265,0.02166748,-0.013847351,-0.010902405,-0.02128601,-0.015060425,-0.032318115,-0.005756378,0.029876709,-0.026763916,-0.018814087,0.017318726,0.0015096664,0.028564453,0.012893677,-0.0004312992,0.013877869,-0.005466461,0.015716553,0.01096344,0.035003662,0.024383545,-0.011894226,-0.037109375,0.027297974,0.0014028549,0.049865723,-0.025817871,-0.029159546,-0.019165039,0.024169922,0.01121521,-0.010238647,-0.0058898926,0.0018510818,-0.04550171,-0.06933594,0.011192322,-0.0115737915,0.04147339,0.026672363,0.010215759,0.026107788,-0.017425537,0.013725281,0.0079422,-0.040252686,-0.026245117,-0.018554688,-0.019348145,-0.006374359,0.002292633,-0.015266418,0.01789856,-0.014373779,0.010848999,0.014678955,-0.0039367676,0.032714844,-0.011779785,0.017364502,0.018478394,0.008743286,0.0037784576,0.027618408,0.018966675,-0.044769287,0.02722168,-0.00065231323,0.016647339,-0.010406494,0.040252686,0.04660034,-0.017074585,-0.0018415451,-0.0007953644,-0.013061523,-0.026138306,0.003332138,0.022964478,0.023803711,-0.0035877228,-0.04083252,0.018249512,0.026168823,-0.034606934,-0.021408081,0.0020008087,0.008384705,-0.0368042,0.018325806,0.0027217865,0.03866577,-0.008132935,-0.0109939575,0.0011844635,0.03189087,0.039978027,-0.0046844482,0.010848999,0.016281128,0.0066566467,0.00025701523,0.011695862,-0.0049972534,0.022705078,0.0044021606,0.018478394,0.0014286041,0.0052986145,-0.008216858,-0.023086548,-0.009552002,0.018676758,-0.011512756,0.034362793,0.0062789917,0.04498291,-0.019454956,0.025787354,0.029205322,-0.041748047,0.0012769699,-0.0038204193,0.044921875,0.008605957,-0.009391785,0.015945435,0.014007568,0.024093628,-0.06732178,-0.014541626,0.006942749,0.027496338,-0.041168213,-0.039245605,-0.051879883,-0.008811951,0.026062012,0.0055389404,0.018035889,0.03274536,-0.018630981,0.0018434525,-0.0046463013,0.010887146,-0.009933472,-0.0052337646,-0.03314209,-0.01979065,-0.005393982,0.0259552,-0.01977539,0.018981934,0.0041046143,-0.029464722,0.0020942688,-0.032592773,0.003862381,-0.007217407,-0.004814148,0.0335083,-0.009841919,0.015037537,-0.021514893,-0.03189087,0.008491516,0.005039215,0.026321411,-0.045196533,0.014732361,-0.013618469,0.010437012,-0.009544373,0.00655365,0.013748169,0.014587402,0.0010375977,0.024902344,-0.058685303,0.031341553,-0.01826477,-0.00724411,-0.000019907951,-0.02760315,-0.0015125275,-0.018493652,0.014122009,0.03805542,-0.008384705,-0.029769897,-0.03744507,-0.07543945,-0.019958496,-0.04864502,0.010475159,0.020706177,0.025619507,-0.04144287,0.009559631,-0.0010070801,0.001036644,-0.006919861,0.001086235,0.015419006,0.046905518,0.026397705,0.02178955,-0.034576416,-0.030075073,-0.008110046,-0.0071105957,-0.008934021,-0.015098572,-0.016586304,0.00042533875,0.022598267,0.003030777,-0.02609253,-0.016693115,-0.005558014,-0.025985718,0.031219482,-0.0022029877,0.011154175,-0.0061035156,-0.025756836,0.0040740967,0.004131317,-0.012535095,0.0158844,0.0054397583,-0.008224487,-0.048675537,-0.00084257126,0.020324707,0.001865387,0.0015468597,-0.048980713,-0.0050697327,-0.026550293,-0.04168701,-0.010154724,-0.014640808,0.009254456,-0.019500732,0.0007920265,-0.06378174,0.008453369,0.0016126633,0.0028495789,0.043792725,0.03125,0.018539429,-0.0076446533,0.009933472,-0.016983032,-0.015525818,-0.039398193,0.012550354,0.010032654,-0.0017280579,0.03994751,0.03970337,0.009239197,-0.02670288,0.0017442703,-0.024765015,0.00667572,-0.010383606,0.026519775,-0.021133423,0.0022411346,0.006401062,-0.013053894,-0.03164673,-0.006752014,0.07891846,-0.0010738373,0.018798828,0.010322571,-0.013442993,0.027069092,0.020050049,-0.025634766,0.0131073,-0.018508911,0.0013208389,-0.015625,0.02734375,-0.005176544,0.014656067,-0.021438599,-0.05255127,-0.001294136,-0.023803711,-0.012519836,-0.06817627,-0.018753052,-0.05142212,0.0035686493,-0.011398315,-0.029205322,0.011260986,0.010406494,-0.0038452148,-0.06890869,0.007904053,0.045074463,-0.016494751,0.020355225,-0.006061554,0.014335632,0.026550293,-0.011962891,-0.00086164474,0.017868042,-0.0524292,-0.012054443,-0.029953003,0.035064697,-0.0031471252,-0.015304565,0.025939941,-0.0035514832,0.008163452,-0.03265381,0.022659302,-0.003730774,-0.0009717941,-0.022079468,-0.0032081604,-0.009941101,0.010803223,0.04711914,-0.035888672,0.029388428,-0.013839722,-0.0041885376,0.010391235,0.024383545,0.052337646,-0.026931763,0.013442993,0.0072135925,0.011314392,0.034454346,-0.03262329,0.03933716,0.026916504,-0.0151901245,0.013427734,0.0077285767,-0.033599854,-0.029418945,-0.019485474,0.033355713,-0.0012569427,0.007724762,-0.008903503,0.009498596,-0.029281616,0.020950317,0.016525269,0.005870819,-0.013015747,-0.0309906,-0.015357971,0.011894226,0.014122009,-0.0076026917,0.020339966,0.027236938,0.03729248,-0.019805908,-0.025115967,0.005630493,0.021453857,0.012001038,-0.0064353943,0.030044556,-0.009483337,0.012702942,0.01737976,0.0067596436,-0.03149414,-0.016098022,-0.027160645,-0.0022678375,0.0006198883,-0.024291992,0.0132369995,0.001584053,-0.002281189,-0.01084137,-0.006298065,0.0052719116,-0.02418518,-0.0071792603,-0.019744873,-0.009788513,0.0368042,0.0077171326,0.003736496,0.031021118,0.0019607544,0.045166016,0.012535095,-0.011161804,0.026290894,0.042388916,0.005996704,-0.03161621,-0.005748749,0.0062789917,-0.006290436,0.01109314,-0.021148682,0.01687622,0.04232788,-0.013084412,0.003993988,0.01197052,0.018005371,-0.019989014,-0.0013980865,-0.004459381,0.029159546,0.010604858,0.010505676,-0.053344727,0.029968262,-0.0024299622,-0.012611389,0.009292603,-0.025253296,-0.016052246,0.031951904,0.0151901245,-0.007881165,0.03704834,-0.009483337,0.050872803,-0.018356323,-0.02558899,0.025878906,-0.01361084,-0.02532959,0.016738892,0.00818634,-0.0023918152,0.012969971,-0.021408081,0.04675293,-0.012870789,-0.0020256042,-0.010047913,-0.0015125275,-0.019256592,-0.02267456,0.00712204,-0.018920898,-0.02418518,-0.00970459,-0.007396698,0.046783447,0.032470703,0.021057129,0.03189087,0.02168274,-0.009880066,-0.042816162,-0.05316162,0.005050659,0.007041931,0.022750854,-0.00844574,0.05105591,0.061798096,0.0060195923,0.013458252,0.028060913,0.037200928,0.0025959015,0.015472412,-0.035705566,0.020431519,-0.0065078735,-0.008850098,0.0025310516,0.043884277,-0.016479492,0.0049057007,-0.007873535,0.02746582,-0.024887085,0.03488159,0.06964111,0.0061836243,0.0033569336,0.015411377,-0.008651733,-0.062683105,0.005619049,-0.026519775,0.04788208,0.014450073,0.045288086,0.05392456,0.015304565,-0.0037174225,0.010765076,-0.021957397,-0.021453857,0.03765869,0.028869629,-0.016021729,-0.0076789856,-0.023239136,0.0008969307,-0.041168213,-0.021133423,0.0020809174,0.009773254,0.0056495667,0.0053901672,-0.0076789856,0.0084991455,0.03225708,0.017364502,-0.0064926147,0.014503479,0.024795532,0.025894165,0.011489868,0.036254883,-0.0071029663,0.01889038,-0.03579712,-0.032318115,0.0021152496,-0.000069499016,-0.007873535,-0.028930664,0.027770996,0.007545471,0.04159546,0.03149414,-0.0062217712,0.017166138,0.013748169,-0.0038108826,0.021743774,0.05102539,0.00818634,-0.0014715195,0.029891968,0.027374268,0.018615723,0.008453369,0.022583008,0.009407043,-0.009559631,-0.00010919571,-0.004005432,0.015014648,-0.0041885376,0.019958496,-0.0066566467,-0.01361084,0.0078048706,0.027908325,-0.00017154217,0.0074806213,0.0046920776,0.018081665,-0.01058197,0.0104522705,-0.0021896362,-0.015022278,0.036499023,0.021362305,0.043518066,-0.0054779053,0.018707275,-0.005180359,-0.021057129,-0.021636963,0.0041885376,-0.045684814,0.0104522705,0.009048462,-0.024093628,-0.043426514,0.020462036,0.0047950745,-0.0053634644,0.04449463,0.03289795,-0.021911621,-0.0022201538,0.037841797,0.00843811,-0.0011892319,0.009124756,-0.023162842,0.009216309,0.04498291,0.021774292,-0.00030088425,-0.039733887,-0.009025574,0.0076065063,0.0044784546,-0.016479492,0.005264282,-0.0065727234,-0.004562378,0.028244019,0.0024642944,0.012336731,0.02558899,-0.023162842,-0.011054993,0.01927185,0.023788452,0.0027542114,-0.01675415,-0.015060425,0.022003174,-0.012199402,0.023956299,0.03869629,0.004802704,0.019577026,0.0042762756,-0.0036773682,-0.009536743,-0.0104904175,0.025009155,-0.019744873,0.004776001,-0.016021729,0.031799316,-0.016830444,-0.011268616,-0.006931305,-0.0046195984,-0.025787354,-0.008392334,0.029815674,0.011367798,0.024124146,0.03010559,0.007904053,-0.03366089,0.059539795,-0.033935547,0.042663574,-0.021377563,0.012710571,0.06652832,0.04425049,0.039489746,-0.009887695,0.02128601,-0.034973145,0.00006711483,0.047027588,0.020965576,0.02684021,-0.008026123,-0.02909851,0.039001465,-0.00390625,0.044677734,-0.03503418,0.0029945374,0.010253906,-0.023284912,-0.01965332,0.00067329407,0.00024354458,0.01134491,0.02494812,-0.03060913,-0.008850098,-0.014205933,-0.012191772,0.011512756,-0.021316528,-0.015113831,0.004589081,-0.020874023,0.004550934,-0.0023384094,-0.004550934,0.020736694,0.022766113,-0.03665161,-0.01574707,0.0011482239,0.023269653,-0.016555786,0.029342651,0.038726807,0.00819397,0.025314331,0.030838013,-0.015167236,0.027526855,-0.005153656,0.019729614,0.045074463,-0.0006389618,-0.010368347,0.023849487,0.0040397644,-0.025268555,0.018630981,0.043426514,0.0019607544,0.009773254,0.0027008057,0.019973755,-0.0043029785,0.004989624,-0.024139404,-0.0032749176,-0.0072517395,-0.03074646,0.0038814545,0.024993896,-0.012435913,0.0049324036,-0.0074691772,-0.010528564,0.0075645447,0.03503418,0.03845215,-0.04006958,-0.0050239563,0.001408577,-0.018096924,-0.014183044,-0.011817932,-0.0055656433,-0.04067993,0.018661499,0.031982422,0.0071029663,0.028167725,-0.019485474,-0.014770508,0.019042969,0.018249512,0.009605408,-0.0084991455,-0.010307312,0.0025787354,-0.02116394,0.006843567,-0.013572693,-0.00919342,0.007888794,0.03274536,-0.0026798248,-0.043518066,0.019805908,-0.02128601,0.005683899,-0.01889038,-0.0010623932,0.027313232,0.004272461,0.00060367584,0.005432129,0.0026798248,-0.009674072,-0.01348114,-0.010475159,0.006389618,0.0546875,0.001411438,-0.007621765,0.01687622,0.043884277,0.014015198,0.03387451,0.0006299019,0.05682373,0.009246826,-0.010444641,-0.03643799,0.0050735474,-0.03265381,-0.013519287,0.01309967,-0.040802002,-0.02243042,0.010154724,0.003452301,-0.015571594,-0.01940918,0.00068950653,-0.01586914,-0.009529114,0.038146973,-0.008544922,0.0024585724,-0.010116577,0.013259888,0.020858765,-0.024627686,-0.052947998,-0.003932953,-0.0074806213,-0.030944824,-0.06317139,0.028289795,-0.027236938,-0.0049934387,-0.010574341,0.0000011920929,0.009681702,0.025512695,-0.011764526,-0.002380371,-0.016098022,0.024017334,0.022735596,0.003967285,0.025039673,-0.03955078,-0.050231934,-0.026779175,-0.019943237,-0.019363403,0.03869629,-0.0026474,0.021621704,0.019058228,-0.021987915,-0.0009160042,-0.0012283325,0.0006580353,-0.011177063,-0.011856079,-0.04714966,0.008811951,0.039123535,-0.011749268,0.0063552856,0.044036865,-0.011497498,-0.020248413,0.01727295,0.036956787,0.008178711,0.020431519,0.009109497,-0.0022678375,-0.0126571655,-0.0056037903,-0.015960693,0.012130737,0.009429932,-0.0019569397,-0.007007599,0.015472412,0.019836426,-0.006828308,0.015014648,0.021575928,0.0000121593475,-0.011077881,0.018539429,0.020095825,0.0052757263,0.000052034855,-0.008354187,-0.005130768,0.06463623,0.025726318,0.011955261,-0.0072250366,0.007633209,-0.019454956,0.002702713,0.020233154,-0.021438599,-0.03741455,-0.01600647,-0.025665283,0.005039215,-0.009429932,0.010505676,-0.0054397583,0.03225708,0.0001450777,-0.053344727,-0.01663208,0.047210693,0.0063819885,-0.01689148,-0.008590698,0.012145996,0.0038108826,-0.035064697,-0.0049476624,-0.050964355,-0.034332275,-0.00217247,-0.0015106201,0.011894226,0.006702423,-0.015434265,0.0070266724,0.013763428,-0.017242432,0.011550903,0.017929077,-0.013954163,0.00071811676,0.0024986267,0.029769897,-0.010475159,0.00712204,-0.005569458,0.0069503784,-0.01737976,-0.024414062,0.027069092,-0.026504517,0.013771057,0.007785797,0.0017604828,0.013916016,0.0076408386,0.0043640137,-0.046539307,0.0015068054,0.009864807,-0.01727295,0.023651123,-0.016052246,-0.027679443,-0.014770508,-0.02281189,-0.039031982,0.01525116,0.028442383,0.016052246,-0.008766174,0.037078857,-0.037200928,0.009765625,-0.005592346,0.013847351,-0.035003662,-0.017349243,0.022613525,-0.023345947,0.0031337738,-0.019104004,-0.00062179565,-0.02659607,-0.020645142,0.0053596497,0.0009880066,0.007045746,0.025894165,0.022384644,0.037261963,0.008575439,0.020355225,0.004005432,-0.00032520294,0.022491455,-0.0063438416,0.045043945,-0.023086548,-0.03253174,-0.009048462,0.0027370453,-0.004562378,-0.002614975,0.007835388,-0.012710571,-0.030639648,0.0033855438,-0.010116577,0.02708435,-0.0028438568,0.02658081,-0.01940918,-0.0027770996,-0.038208008,-0.0061416626,-0.037261963,0.01524353,0.029312134,0.020065308,0.004005432,-0.026992798,-0.02619934,0.023162842,0.010520935,0.012565613,-0.0435791,-0.038146973,0.0017404556,0.0036830902,0.003118515,0.022827148,-0.03503418,-0.013259888,0.009468079,0.005832672,0.0054244995,0.0076141357,0.016326904,-0.0039787292,-0.006008148,0.00008016825,0.024810791,-0.018630981,-0.0017614365,-0.014274597,-0.010482788,0.040008545,0.009376526,-0.026504517,0.017944336,0.026351929,-0.034301758,0.05239868,-0.019180298,0.0015687943,-0.009925842,0.004146576,-0.042877197,-0.014205933,0.012199402,-0.0019569397],"createdAt":"2026-04-21T18:32:12.354Z","updatedAt":"2026-04-22T02:31:50.548Z","lastSeenAt":"2026-04-22T02:31:50.548Z","tsv":"'/api/v1/emails/50/attachments':124 '0.02':10,22,61,73,114 '000':67 '20':66 '402':194 '50':38 '6':71 'Base USDC API' 'accept':45 'access':30 'actual':177 'ai/ml':98 'analysi':101 'analyt':97 'api':76,94,136 'attach':3,15,33 'base':8,20,58,68 'behavior':178 'behind':39 'beyond':127 'bodi':207 'broader':88 'call':63 'caller':197 'challeng':195 'classif':103 'confirm':188 'connect':145 'cover':121 'data':96,107 'decim':72 'describ':165 'detail':152 'discov':203 'doc':135 'document':126,164 'email':2,14,32,36 'email attachment API' 'email-attachments' 'embed':104 'endpoint':26,44,125,181,186 'exampl':161 'expect':205 'experi':201 'extrem':132 'field':167 'finance/crypto':105 'format':210 'gate':93 'host':86 'howev':117 'id':37 'infer':99 'infrastructur':109 'json':50 'key':77 'land':129 'larg':183 'like':175 'limit':79 'list':120 'live':189 'look':174 'lowpaymentfee email' 'lowpaymentfee.com':28,85 'market':106 'maxamountrequir':64 'micropay':6,18 'micropayment' 'micropayment email attachments' 'need':199 'network':59 'no-api-key' 'openapi':157 'page':130,140 'pay-per-call email' 'pay-per-request' 'payment':51 'paywal':42 'per':11,23,62,115 'post':46 'price':112,137 'prompt':147 'provid':29,84 'rate':78 'readm':139 'render':142 'request':12,24,47,116,206 'request/response':160 'requir':82 'respons':173,209 'retriev':1,13 'return':49,190 'schema':158 'send':169 'sentiment':100 'settl':53 'span':95 'spars':133 'specif':34,119 'subscript':81 'suit':89 'summar':102 'technic':151 'unit':69 'unknown':184 'usdc':55 'usdc-base' 'util':110 'valid':192 'via':4,16 'wallet':146 'x402':5,17,41,92,193 'x402 email endpoint' 'x402-gated':91 'x402-payment'","prices":[{"id":"0ae9b323-422b-410c-9f1f-b57465054f35","listingId":"ecc577bb-a838-44cc-989a-9bbd19376fe9","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/emails/50/attachments","description":"Premium API Access","outputSchema":{"input":{"type":"http","method":"GET","discoverable":true}},"maxAmountRequired":"20000","maxTimeoutSeconds":300}],"asset_contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","max_timeout_seconds":300},"createdAt":"2026-04-21T18:32:12.354Z"}],"sources":[{"listingId":"ecc577bb-a838-44cc-989a-9bbd19376fe9","source":"x402_bazaar","sourceId":"https://lowpaymentfee.com/api/v1/emails/50/attachments","sourceUrl":"https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources","isPrimary":true,"firstSeenAt":"2026-04-21T18:32:12.354Z","lastSeenAt":"2026-04-22T02:31:50.548Z"}],"details":{"listingId":"ecc577bb-a838-44cc-989a-9bbd19376fe9","quickStartSnippet":"curl -X POST https://lowpaymentfee.com/api/v1/emails/50/attachments \\\n  -H \"Content-Type: application/json\" \\\n  -H \"X-PAYMENT: <x402_payment_token>\" \\\n  -d '{}'","exampleRequest":null,"exampleResponse":null,"schema":{"input":{"type":"http","method":"GET","discoverable":true}},"openapiUrl":null,"agentsTxtUrl":null,"citations":[{"claim":"Endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 in USDC on Base","source_url":"https://lowpaymentfee.com/api/v1/emails/50/attachments"},{"claim":"All APIs on lowpaymentfee.com are priced at $0.02 per request with no API keys, no rate limits","source_url":"https://lowpaymentfee.com"},{"claim":"USDC asset address 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base network","source_url":"https://lowpaymentfee.com/api/v1/emails/50/attachments"}],"useCases":["Retrieving attachments from a specific email via programmatic API call","Agent-driven email attachment fetching with per-request crypto payment","Integrating email attachment access into automated workflows without API key management"],"bestFor":["Agents or bots that need on-demand email attachment retrieval with no signup","Developers experimenting with x402 micropayment protocols","Workflows requiring keyless, pay-per-use API access on Base"],"notFor":["Bulk email processing or mailbox-level access","Users who need detailed API documentation or guaranteed SLAs","Non-crypto users who cannot pay in USDC on Base"],"kindDetails":{"x402_version":1,"resource_type":"http","bazaar_last_updated":"2026-02-17T23:13:20.857Z"},"updatedAt":"2026-04-22T02:31:50.548Z"}}