{"id":100200,"date":"2026-02-15T20:26:24","date_gmt":"2026-02-15T20:26:24","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100200"},"modified":"2026-04-05T15:35:22","modified_gmt":"2026-04-05T15:35:22","slug":"proximity-probe-setup","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/sw\/calculators\/proximity-probe-setup\/","title":{"rendered":"Proximity Probe Gap Voltage Calculator | Vibromera"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Proximity Probe Gap Voltage Calculator\",\"description\":\"Eddy current proximity probe gap voltage and linearity range calculator.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/proximity-probe-setup\/\",\"applicationCategory\":\"Engineering Calculator\",\"operatingSystem\":\"Any (Web Browser)\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"EUR\"},\"creator\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"datePublished\":\"2024-01-01\",\"dateModified\":\"2025-02-14\",\"inLanguage\":\"en\",\"isAccessibleForFree\":true}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"How does an eddy current proximity probe work?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"An eddy current probe generates a high-frequency magnetic field. When a conductive target (shaft) enters this field, eddy currents are induced, which change the probe's impedance. The proximitor driver converts this impedance change to a voltage proportional to the gap distance.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the standard sensitivity for proximity probes?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The most common sensitivity is 200 mV\/mil (7.87 V\/mm) for API 670 compliant systems. European systems often use 8 mV\/\u03bcm. The relationship is linear within the specified range.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the normal gap voltage setting?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"API 670 recommends a gap voltage of \u221210V DC (corresponding to approximately 50 mil or 1.27 mm gap) for standard 200 mV\/mil probes. This centers the measurement in the linear range.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the linear range of a proximity probe?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"For standard 8mm probes: 0.25\u20132.3 mm (10\u201390 mil). For 5mm probes: 0.25\u20131.3 mm (10\u201350 mil). For 12mm probes: 0.5\u20134.0 mm (20\u2013160 mil). Output is linear within \u00b15% in this range.\"}},\n{\"@type\":\"Question\",\"name\":\"What target material affects sensitivity?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Probes are calibrated for 4140 steel. Other materials have different sensitivities: stainless steel (AISI 304) ~0.85\u00d7, aluminum ~0.40\u00d7, brass ~0.50\u00d7, titanium ~0.60\u00d7. Material correction factors must be applied.\"}}\n]}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"BreadcrumbList\",\"itemListElement\":[\n{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/vibromera.eu\/\"},\n{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Calculators\",\"item\":\"https:\/\/vibromera.eu\/calculators\/\"},\n{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Proximity Probe Setup\",\"item\":\"https:\/\/vibromera.eu\/calculators\/proximity-probe-setup\/\"}\n]}\n<\/script>\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&#038;family=JetBrains+Mono:wght@400;500;600&#038;family=Fraunces:opsz,wght@9..144,700;9..144,800&#038;display=swap\" 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16px;font-size:13px;color:var(--vc-ink-muted)}.vc-footer a{color:var(--vc-accent);text-decoration:none}.vc-footer a:hover{text-decoration:underline}.vc-footer-links{margin-top:8px;font-size:12px}.vc-footer-links a{margin:0 8px}\n@media print{.vc-section-body{max-height:none!important}.vc-faq-a{max-height:none!important}.vc-results{max-height:none!important;padding:24px!important}.vc-copy-btn,.vc-section-chevron,.vc-faq-chevron,.vc-presets,.vc-promo{display:none!important}}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-proximity-probe\">\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool \u2014 #031<\/p>\n    <h1 class=\"vc-header-title\">Proximity Probe Gap Voltage Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Calculate eddy current probe gap voltage, gap distance from voltage, and verify linear operating range. For shaft vibration and position measurement setup per API 670.<\/p>\n    <div class=\"vc-badges\"><span class=\"vc-badge\">API 670<\/span><span class=\"vc-badge\">Eddy Current<\/span><span class=\"vc-badge\">Gap Voltage<\/span><\/div>\n<\/header>\n\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-gap\">Gap Distance <span class=\"vc-label-hint\">(mm)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-gap\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 1.27\" value=\"1.27\"><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-sens\">Sensitivity Factor <span class=\"vc-label-hint\">(mV\/\u03bcm)<\/span><\/label><input class=\"vc-input\" type=\"number\" id=\"vc-sens\" inputmode=\"decimal\" step=\"any\" min=\"0.1\" placeholder=\"e.g. 7.87\" value=\"7.87\"><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-probe\">Probe Size<\/label><select class=\"vc-select\" id=\"vc-probe\"><option value=\"5\">5 mm (3300 series)<\/option><option value=\"8\" selected>8 mm (3300 series \u2014 standard)<\/option><option value=\"12\">12 mm (for large gaps)<\/option><\/select><\/div>\n            <div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-material\">Target Material<\/label><select class=\"vc-select\" id=\"vc-material\"><option value=\"1.0\" selected>4140 Steel (standard cal)<\/option><option value=\"0.85\">Stainless Steel (304)<\/option><option value=\"0.60\">Titanium<\/option><option value=\"0.50\">Brass<\/option><option value=\"0.40\">Aluminum<\/option><\/select><\/div>\n        <\/div>\n        <div class=\"vc-presets\">\n            <div class=\"vc-presets-label\">Quick presets<\/div>\n            <button type=\"button\" class=\"vc-preset-btn\" data-g=\"1.27\" data-s=\"7.87\" data-p=\"8\" data-m=\"1.0\">API 670 standard (\u221210 V target)<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-g=\"0.75\" data-s=\"7.87\" data-p=\"8\" data-m=\"1.0\">Close gap 0.75 mm<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-g=\"2.0\" data-s=\"7.87\" data-p=\"8\" data-m=\"1.0\">Wide gap 2.0 mm<\/button>\n        <\/div>\n    <\/form>\n\n    <div class=\"vc-results\" id=\"vc-results\">\n        <div class=\"vc-results-head\"><h2 class=\"vc-results-title\">Results<\/h2><button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\"><svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy<\/button><\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\"><div class=\"vc-rcard-label\">Gap Voltage (DC)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-voltage\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Gap Distance<\/div><div class=\"vc-rcard-value\" id=\"vc-r-gap\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Linear Range<\/div><div class=\"vc-rcard-value\" id=\"vc-r-range\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">In Linear Range?<\/div><div class=\"vc-rcard-value\" id=\"vc-r-inrange\">\u2014<\/div><\/div>\n            <div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Effective Sensitivity<\/div><div class=\"vc-rcard-value\" id=\"vc-r-effsens\">\u2014<\/div><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<div class=\"vc-section vc-open\" id=\"vc-sec-theory\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udcd8<\/span><span class=\"vc-section-title\">Theory &amp; Formulas<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner vc-theory\">\n            <h3>Gap Voltage Relationship<\/h3>\n            <div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div>\n            <p>Output is negative voltage (closer gap \u2192 more negative). Standard sensitivity: 7.87 mV\/\u03bcm = 200 mV\/mil.<\/p>\n            <h3>Linear Ranges by Probe Size<\/h3>\n            <table class=\"vc-table\">\n                <thead><tr><th>Probe<\/th><th>Linear Range (mm)<\/th><th>Linear Range (mil)<\/th><th>Voltage Range<\/th><\/tr><\/thead>\n                <tbody>\n                    <tr><td>5 mm<\/td><td>0.25 \u2013 1.30<\/td><td>10 \u2013 50<\/td><td>\u22122 to \u221210 V<\/td><\/tr>\n                    <tr><td>8 mm<\/td><td>0.25 \u2013 2.30<\/td><td>10 \u2013 90<\/td><td>\u22122 to \u221218 V<\/td><\/tr>\n                    <tr><td>12 mm<\/td><td>0.50 \u2013 4.00<\/td><td>20 \u2013 160<\/td><td>\u22124 to \u221232 V<\/td><\/tr>\n                <\/tbody>\n            <\/table>\n            <div class=\"vc-example-box\">\n                <div class=\"vc-example-title\">Example \u2014 Standard API 670 Setup<\/div>\n                <p><strong>Given:<\/strong> 8 mm probe, 7.87 mV\/\u03bcm, 4140 steel target<\/p>\n                <p>Target gap = 1.27 mm = 1270 \u03bcm \u2192 V = \u22127.87 \u00d7 1270 \/ 1000 = <strong>\u22129.99 V DC \u2248 \u221210 V<\/strong><\/p>\n                <p>Linear range: 0.25\u20132.30 mm \u2192 1.27 mm is centered \u2713<\/p>\n            <\/div>\n            <div class=\"vc-warning-box\"><p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary);\"><strong>\u26a0\ufe0f Note:<\/strong> Non-steel targets require sensitivity correction. Operating outside the linear range causes measurement errors &gt; 5%.<\/p><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<div class=\"vc-section\" id=\"vc-sec-related\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\ud83d\udd17<\/span><span class=\"vc-section-title\">Related Calculators<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div class=\"vc-related\">\n        <a class=\"vc-related-link\" href=\"\/calculators\/vibration-sensor-sensitivity\/\">Sensor Sensitivity<\/a>\n        <a class=\"vc-related-link\" href=\"\/calculators\/condition-monitoring-iso13373\/\">Condition Monitoring (ISO 13373)<\/a>\n        <a class=\"vc-related-link\" href=\"\/calculators\/vibration-overall-level\/\">Overall Vibration Level<\/a>\n        <a class=\"vc-related-link\" href=\"\/calculators\/vibration-phase-angle\/\">Phase Angle Calculator<\/a>\n    <\/div><\/div><\/div>\n<\/div>\n\n<div class=\"vc-section\" id=\"vc-sec-faq\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\"><span class=\"vc-section-toggle-text\"><span class=\"vc-section-icon\">\u2753<\/span><span class=\"vc-section-title\">Frequently Asked Questions<\/span><\/span><svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button>\n    <div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div><\/div><\/div>\n<\/div>\n\n<div class=\"vc-promo\"><div class=\"vc-promo-text\"><strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>Professional vibration measurement and shaft monitoring solutions. Proximity probe compatible instruments. Used in 50+ countries.<\/div><a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a><\/div>\n\n<footer class=\"vc-footer\"><p>\u00a9 2024\u20132025 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p><p style=\"font-size:12px;margin-top:4px;\">Proximity probe gap voltage calculator. Last updated: February 2025<\/p><div class=\"vc-footer-links\"><a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a><a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a><\/div><\/footer>\n<\/div>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.js\"><\/script>\n<script>\n(function(){\n    'use strict';\n    var SLUG='proximity-probe-setup';\n    function $(id){return document.getElementById(id)}\n    function fmt(n,d){if(isNaN(n)||!isFinite(n))return '\u2014';return n.toFixed(d===undefined?2:d).replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,'')}\n\n    var ranges={'5':[0.25,1.30],'8':[0.25,2.30],'12':[0.50,4.00]};\n\n    function calculate(){\n        var gap=parseFloat($('vc-gap').value);\n        var sens=parseFloat($('vc-sens').value);\n        var probe=$('vc-probe').value;\n        var matFactor=parseFloat($('vc-material').value);\n        if(!gap||gap<0||!sens||sens<=0){$('vc-results').classList.remove('vc-visible');return}\n\n        var effSens=sens*matFactor;\n        var gapUm=gap*1000;\n        var voltage=-(effSens*gapUm)\/1000; \/\/ V\n        var gapMil=gap\/0.0254;\n        var r=ranges[probe];\n        var inRange=gap>=r[0]&&gap<=r[1];\n\n        $('vc-r-voltage').innerHTML=fmt(voltage,2)+' <span class=\"vc-rcard-unit\">V DC<\/span>';\n        $('vc-r-gap').innerHTML=fmt(gap,3)+' <span class=\"vc-rcard-unit\">mm<\/span> <span class=\"vc-rcard-unit\">('+fmt(gapMil,1)+' mil)<\/span>';\n        $('vc-r-range').innerHTML=fmt(r[0],2)+'\u2013'+fmt(r[1],2)+' <span class=\"vc-rcard-unit\">mm<\/span>';\n        $('vc-r-inrange').innerHTML=inRange?'<span style=\"color:var(--vc-green)\">YES \u2713<\/span>':'<span style=\"color:var(--vc-red)\">NO \u2014 Outside linear range<\/span>';\n        $('vc-r-effsens').innerHTML=fmt(effSens,2)+' <span class=\"vc-rcard-unit\">mV\/\u03bcm<\/span>'+(matFactor<1?' <span class=\"vc-rcard-unit\">(corrected)<\/span>':'');\n        $('vc-results').classList.add('vc-visible');\n        saveHistory({gap:gap,voltage:fmt(voltage,2),probe:probe,_summary:gap+'mm \u2192 '+fmt(voltage,2)+'V, '+(inRange?'in range':'OUT OF RANGE')});\n    }\n\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn){btn.addEventListener('click',function(e){e.preventDefault();$('vc-gap').value=this.getAttribute('data-g');$('vc-sens').value=this.getAttribute('data-s');$('vc-probe').value=this.getAttribute('data-p');$('vc-material').value=this.getAttribute('data-m');calculate()})});\n    $('vc-form').addEventListener('input',calculate);$('vc-form').addEventListener('change',calculate);\n\n    $('vc-copy-btn').addEventListener('click',function(){var text='Proximity Probe Setup\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nGap: '+$('vc-r-gap').textContent+'\\nVoltage: '+$('vc-r-voltage').textContent+'\\nLinear Range: '+$('vc-r-range').textContent+'\\nIn Range: '+$('vc-r-inrange').textContent+'\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nvibromera.eu\/calculators\/proximity-probe-setup\/';if(navigator.clipboard){navigator.clipboard.writeText(text).then(function(){var b=$('vc-copy-btn');b.classList.add('vc-copied');b.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><polyline points=\"20 6 9 17 4 12\"\/><\/svg> Copied!';setTimeout(function(){b.classList.remove('vc-copied');b.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy'},2000)})}});\n\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn){btn.addEventListener('click',function(){var s=this.closest('.vc-section');s.classList.toggle('vc-open');this.setAttribute('aria-expanded',s.classList.contains('vc-open'))})});\n\n    var faqData=[\n        {q:'How does an eddy current proximity probe work?',a:'<p>A high-frequency magnetic field is generated by the probe. When a conductive target enters this field, eddy currents change the probe impedance. The proximitor converts this to a voltage proportional to gap distance.<\/p>'},\n        {q:'What is the standard sensitivity?',a:'<p>200 mV\/mil = 7.87 mV\/\u03bcm for API 670 systems. European: 8 mV\/\u03bcm. The relationship is linear within the specified range. Calibrated for 4140 steel.<\/p>'},\n        {q:'What is the normal gap voltage setting?',a:'<p>API 670 recommends \u221210V DC (\u224850 mil = 1.27 mm) for standard 8mm\/200 mV\/mil probes. This centers measurement in the linear range for maximum dynamic range.<\/p>'},\n        {q:'What is the linear range?',a:'<p>8mm probes: 0.25\u20132.3 mm. 5mm: 0.25\u20131.3 mm. 12mm: 0.5\u20134.0 mm. Output is linear within \u00b15% in this range. Outside: errors increase rapidly.<\/p>'},\n        {q:'What target material affects sensitivity?',a:'<p>Calibrated for 4140 steel. Correction factors: stainless 304 \u2248 0.85\u00d7, titanium \u2248 0.60\u00d7, brass \u2248 0.50\u00d7, aluminum \u2248 0.40\u00d7. 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Calculate gap distance, output voltage, and linearity range for shaft vibration and position measurements.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100200","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/calculator\/100200","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":2,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/calculator\/100200\/revisions"}],"predecessor-version":[{"id":100914,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/calculator\/100200\/revisions\/100914"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/media?parent=100200"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/categories?post=100200"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/sw\/wp-json\/wp\/v2\/tags?post=100200"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}