diff --git a/functions/graphql/resolvers.js b/functions/graphql/resolvers.js
index e9a2f3d..df57721 100644
--- a/functions/graphql/resolvers.js
+++ b/functions/graphql/resolvers.js
@@ -1,45 +1,59 @@
-const { parsePaymentRequest } = require('invoices');
-const axios = require('axios');
-const { createHash } = require('crypto');
+const { parsePaymentRequest } = require("invoices");
+const axios = require("axios");
+const { createHash } = require("crypto");
 
-function hexToUint8Array (hexString) {
+function hexToUint8Array(hexString) {
   const match = hexString.match(/.{1,2}/g);
   if (match) {
     return new Uint8Array(match.map((byte) => parseInt(byte, 16)));
   }
 }
 
-// TODO validate responses
-function getPaymetRequest(lightning_address, amount_in_sat) {
+// TODO: generaly validate LNURL responses
+
+function getLnurlDetails(lnurl) {
+  return axios.get(lnurl);
+}
+
+function lightningAddressToLnurl(lightning_address) {
   const [name, domain] = lightning_address.split("@");
-  const lnurl = `https://${domain}/.well-known/lnurlp/${name}`;
-  return axios.get(lnurl)
-    .then((response) => {
-      console.log(response.data);
-      const callbackUrl = response.data.callback;
-      const amount = amount_in_sat * 1000; // msats
-      return axios.get(callbackUrl, { params: { amount }} )
-        .then(prResponse => {
-          console.log(prResponse.data);
-          return prResponse.data.pr;
-        });
-    })
-    .catch(function (error) {
-      console.error(error);
-    })
+  return `https://${domain}/.well-known/lnurlp/${name}`;
+}
+
+async function getLnurlCallbackUrl(lightning_address) {
+  return getLnurlDetails(lightningAddressToLnurl(lightning_address)).then(
+    (response) => {
+      return response.data.callback;
+    }
+  );
+}
+
+async function getPaymetRequestForProject(project, amount_in_sat) {
+  let lnurlCallbackUrl = project.lnurl_callback_url;
+  const amount = amount_in_sat * 1000; // msats
+  console.log(lnurlCallbackUrl);
+  if (!lnurlCallbackUrl) {
+    lnurlCallbackUrl = await getLnurlCallbackUrl(project.lightning_address);
+  }
+  return axios
+    .get(lnurlCallbackUrl, { params: { amount } })
+    .then((prResponse) => {
+      console.log(prResponse.data);
+      return prResponse.data.pr;
+    });
 }
 
 module.exports = {
   Query: {
     allCategories: async (_source, args, context) => {
       return context.prisma.category.findMany({
-        orderBy: { title: 'desc'},
+        orderBy: { title: "desc" },
         include: {
           project: {
             take: 5,
-            orderBy: { votes_count: "desc" }
-          }
-        }
+            orderBy: { votes_count: "desc" },
+          },
+        },
       });
     },
     getCategory: async (_source, args, context) => {
@@ -48,16 +62,16 @@ module.exports = {
         include: {
           project: {
             take: 5,
-            orderBy: { votes_count: "desc" }
-          }
-        }
+            orderBy: { votes_count: "desc" },
+          },
+        },
       });
     },
     newProjects: async (_source, args, context) => {
       const take = args.take || 50;
       const skip = args.skip || 0;
       return context.prisma.project.findMany({
-        orderBy: { created_at: 'desc' },
+        orderBy: { created_at: "desc" },
         include: { category: true },
         skip,
         take,
@@ -67,7 +81,7 @@ module.exports = {
       const take = args.take || 50;
       const skip = args.skip || 0;
       return context.prisma.project.findMany({
-        orderBy: { votes_count: 'desc' },
+        orderBy: { votes_count: "desc" },
         include: { category: true },
         skip,
         take,
@@ -79,7 +93,7 @@ module.exports = {
       const categoryId = args.category_id;
       return context.prisma.project.findMany({
         where: { category_id: categoryId },
-        orderBy: { votes_count: 'desc' },
+        orderBy: { votes_count: "desc" },
         include: { category: true },
         skip,
         take,
@@ -90,14 +104,47 @@ module.exports = {
         where: {
           id: args.id,
         },
-        include: { category: true }
+        include: { category: true },
       });
     },
+    getLnurlDetailsForProject: async (_source, args, context) => {
+      const project = await context.prisma.project.findUnique({
+        where: {
+          id: args.project_id,
+        },
+      });
+      const lnurlDetails = await getLnurlDetails(
+        lightningAddressToLnurl(project.lightning_address)
+      );
+      if (
+        !lnurlDetails.data ||
+        lnurlDetails.data.status.toLowerCase() !== "ok"
+      ) {
+        console.error(lnurlDetails.data);
+        throw new Error("Recipient not available");
+      }
+
+      // cache the callback URL
+      await context.prisma.project.update({
+        where: { id: project.id },
+        data: {
+          lnurl_callback_url: lnurlDetails.data.callback,
+        },
+      });
+      return {
+        minSendable: parseInt(lnurlDetails.data.minSendable) / 1000,
+        maxSendable: parseInt(lnurlDetails.data.maxSendable) / 1000,
+        metadata: lnurlDetails.data.metadata,
+        commentAllowed: lnurlDetails.data.commentAllowed,
+      };
+    },
   },
   Mutation: {
     vote: async (_source, args, context) => {
-      const project = await context.prisma.project.findUnique({where: { id: args.project_id }});
-      const pr = await getPaymetRequest(project.lightning_address, args.amount_in_sat);
+      const project = await context.prisma.project.findUnique({
+        where: { id: args.project_id },
+      });
+      const pr = await getPaymetRequestForProject(project, args.amount_in_sat);
       const invoice = parsePaymentRequest({ request: pr });
       return context.prisma.vote.create({
         data: {
@@ -105,23 +152,32 @@ module.exports = {
           amount_in_sat: args.amount_in_sat,
           payment_request: pr,
           payment_hash: invoice.id,
-        }
+        },
       });
     },
     confirmVote: async (_source, args, context) => {
-      const paymentHash = createHash('sha256').update(hexToUint8Array(args.preimage)).digest('hex');
+      const paymentHash = createHash("sha256")
+        .update(hexToUint8Array(args.preimage))
+        .digest("hex");
       // look for a vote for the payment request and the calculated payment hash
-      const vote = await context.prisma.vote.findFirst({where: { payment_request: args.payment_request, payment_hash: paymentHash}});
+      const vote = await context.prisma.vote.findFirst({
+        where: {
+          payment_request: args.payment_request,
+          payment_hash: paymentHash,
+        },
+      });
       // if we find a vote it means the preimage is correct and we update the vote and mark it as paid
       // can we write this nicer?
       if (vote) {
-        const project = await context.prisma.project.findUnique({ where: { id: vote.project_id }});
+        const project = await context.prisma.project.findUnique({
+          where: { id: vote.project_id },
+        });
         // count up votes cache
         await context.prisma.project.update({
-          where: {id: project.id },
+          where: { id: project.id },
           data: {
-            votes_count: project.votes_count = vote.amount_in_sat,
-          }
+            votes_count: (project.votes_count = vote.amount_in_sat),
+          },
         });
         // return the current vote
         return context.prisma.vote.update({
@@ -129,11 +185,11 @@ module.exports = {
           data: {
             paid: true,
             preimage: args.preimage,
-          }
+          },
         });
       } else {
         throw new Error("Invalid preimage");
       }
-    }
+    },
   },
 };
diff --git a/functions/graphql/typeDefs.js b/functions/graphql/typeDefs.js
index c96f23b..82b49f5 100644
--- a/functions/graphql/typeDefs.js
+++ b/functions/graphql/typeDefs.js
@@ -27,6 +27,13 @@ module.exports = gql`
     paid: Boolean!
   }
 
+  type LnurlDetails {
+    minSendable: Int
+    maxSendable: Int
+    metadata: String
+    commentAllowed: Int
+  }
+
   type Query {
     allProjects(skip: Int, take: Int): [Project]!
     newProjects(skip: Int, take: Int): [Project]!
@@ -34,9 +41,10 @@ module.exports = gql`
     getProject(id: Int!): Project!
     allCategories: [Category]!
     getCategory(id: Int!): Category!
+    getLnurlDetailsForProject(project_id: Int!): LnurlDetails!
   }
   type Mutation {
-    vote (project_id: Int!, amount_in_sat: Int!): Vote!
-    confirmVote (payment_request: String!, preimage: String!): Vote!
+    vote(project_id: Int!, amount_in_sat: Int!): Vote!
+    confirmVote(payment_request: String!, preimage: String!): Vote!
   }
 `;
diff --git a/prisma/migrations/20211129045548_add_lnurl_callback_url_to_project/migration.sql b/prisma/migrations/20211129045548_add_lnurl_callback_url_to_project/migration.sql
new file mode 100644
index 0000000..8045323
--- /dev/null
+++ b/prisma/migrations/20211129045548_add_lnurl_callback_url_to_project/migration.sql
@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "Project" ADD COLUMN     "lnurl_callback_url" TEXT;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 87cd39e..40179d0 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -14,18 +14,19 @@ model Category {
 }
 
 model Project {
-  id                Int      @id @default(autoincrement())
-  title             String
-  description       String
-  website           String
-  thumbnail_image   String?
-  cover_image       String?
-  lightning_address String?
-  category          Category @relation(fields: [category_id], references: [id])
-  category_id       Int
-  votes_count       Int      @default(0)
-  vote              Vote[]
-  created_at        DateTime @default(now())
+  id                 Int      @id @default(autoincrement())
+  title              String
+  description        String
+  website            String
+  thumbnail_image    String?
+  cover_image        String?
+  lightning_address  String?
+  lnurl_callback_url String?
+  category           Category @relation(fields: [category_id], references: [id])
+  category_id        Int
+  votes_count        Int      @default(0)
+  vote               Vote[]
+  created_at         DateTime @default(now())
 }
 
 model Vote {