diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 0000000..9ff064c
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,7 @@
+{
+  "semi": false,
+  "singleQuote": true,
+  "printWidth": 90,
+  "trailingComma": "none",
+  "tabWidth": 2
+}
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
new file mode 100644
index 0000000..5901167
--- /dev/null
+++ b/.vscode/extensions.json
@@ -0,0 +1,7 @@
+{
+  "recommendations": [
+    "dbaeumer.vscode-eslint",
+    "esbenp.prettier-vscode",
+    "wix.vscode-import-cost"
+  ]
+}
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..171c9cd
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,17 @@
+{
+  "editor.codeActionsOnSave": {
+    "source.fixAll.eslint": true
+  },
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "editor.formatOnSave": true,
+  "eslint.validate": [
+    "javascript",
+    "javascriptreact",
+    "typescript",
+    "typescriptreact"
+  ],
+  "search.exclude": {
+    "**/.next": true,
+    "**/out": true
+  }
+}
diff --git a/app/controllers/upload.controller.js b/app/controllers/upload.controller.js
index c9a602f..4063b10 100644
--- a/app/controllers/upload.controller.js
+++ b/app/controllers/upload.controller.js
@@ -1,503 +1,568 @@
-const Bundlr = require("@bundlr-network/client");
+const Bundlr = require('@bundlr-network/client')
 
-const axios = require('axios');
-const File = require("../models/upload.model.js");
-const Quote = require("../models/quote.model.js");
-const Nonce = require("../models/nonce.model.js");
-const ethers = require('ethers');
-const { getToken } = require("./tokens.js");
-const { errorResponse } = require("./error.js");
-const MIN_GAS_FEE_POLYGON = 30000000000; // 30 gwei
+const axios = require('axios')
+const File = require('../models/upload.model.js')
+const Quote = require('../models/quote.model.js')
+const Nonce = require('../models/nonce.model.js')
+const ethers = require('ethers')
+const { getToken } = require('./tokens.js')
+const { errorResponse } = require('./error.js')
+const MIN_GAS_FEE_POLYGON = 30000000000 // 30 gwei
 
 exports.upload = async (req, res) => {
-	console.log(`upload request: ${JSON.stringify(req.body)}`)
-
-	// Validate request
-	if(!req.body) {
-		errorResponse(req, res, null, 400, "Content can not be empty!");
-		return;
-	}
-
-	// validate fields
-	const quoteId = req.body.quoteId;
-	if(typeof quoteId === "undefined") {
-		errorResponse(req, res, null, 400, "Missing quoteId.");
-		return;
-	}
-	if(typeof quoteId !== "string") {
-		errorResponse(req, res, null, 400, "Invalid quoteId.");
-		return;
-	}
-
-	const files = typeof req.body.files === 'string' ? [req.body.files] : req.body.files;
-	if(typeof files === "undefined") {
-		errorResponse(req, res, null, 400, "Missing files field.");
-		return;
-	}
-	if(typeof files !== "object" || !Array.isArray(files)) {
-		errorResponse(req, res, null, 400, "Invalid files field.");
-		return;
-	}
-	if(files.length == 0) {
-		errorResponse(req, res, null, 400, "Empty files field.");
-		return;
-	}
-
-	if(files.length > 64) {
-		errorResponse(req, res, null, 400, "Too many files. Max 64.");
-		return;
-	}
-
-	const cidRegex = /^(Qm[1-9A-HJ-NP-Za-km-z]{44,}|b[A-Za-z2-7]{58,}|B[A-Z2-7]{58,}|z[1-9A-HJ-NP-Za-km-z]{48,}|F[0-9A-F]{50,})$/i;
-	for(let i = 0; i < files.length; i++) {
-		if(typeof files[i] !== "string") {
-			errorResponse(req, res, null, 400, `Invalid files field on index ${i}.`);
-			return;
-		}
-		// TODO: validate URL format better
-		if(!files[i].startsWith('ipfs://')) {
-			errorResponse(req, res, null, 400, `Invalid protocol on index ${i}. Must be ipfs://<CID>`);
-			return;
-		}
-		if(!cidRegex.test(files[i].substring(7))) {
-			errorResponse(req, res, null, 400, `Invalid CID on index ${i}.`);
-			return;
-		}
-	}
-
-	if (typeof req.body.nonce === "undefined") {
-		errorResponse(req, res, null, 400, "Missing nonce.");
-		return;
-	}
-	
-	const nonce = Number(req.body.nonce);
-	
-	if (isNaN(nonce)) {
-		errorResponse(req, res, null, 400, "Invalid nonce.");
-		return;
-	}
-
-	const signature = req.body.signature;
-	if(typeof signature === "undefined") {
-		errorResponse(req, res, null, 400, "Missing signature.");
-		return;
-	}
-	if(typeof signature !== "string") {
-		errorResponse(req, res, null, 400, "Invalid signature.");
-		return;
-	}
-
-	// validate quote
-	let quote;
-	try {
-		quote = Quote.get(quoteId);
-		if(quote == undefined) {
-			errorResponse(req, res, null, 404, "Quote not found.");
-			return;
-		}
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, "Error occurred while validating quote.");
-		return;
-	}
-
-	const userAddress = quote.userAddress;
-	const message = ethers.utils.sha256(ethers.utils.toUtf8Bytes(quoteId + nonce.toString()));
-	let signerAddress;
-	try {
-		signerAddress = ethers.utils.verifyMessage(message, signature);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 403, "Invalid signature.");
-		return;
-	}
-
-	if(signerAddress != userAddress) {
-		errorResponse(req, res, null, 403, "Invalid signature.");
-		return;
-	}
-
-	let oldNonce;
-	try {
-		oldNonce = Nonce.get(userAddress)?.nonce || 0.0;
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, "Error occurred while validating nonce.");
-		return;
-	}
-	if(parseFloat(nonce) <= parseFloat(oldNonce)) {
-		errorResponse(req, res, null, 403, "Invalid nonce.");
-		return;
-	}
-	try {
-		Nonce.set(userAddress, nonce);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, "Error occurred while storing nonce.");
-		return;
-	}
-
-	// check status of quote
-	if(quote.status != Quote.QUOTE_STATUS_WAITING) {
-		if(quote.status == Quote.QUOTE_STATUS_UPLOAD_END) {
-			errorResponse(req, res, null, 400, "Quote has been completed.");
-			return;
-		}
-		else {
-			errorResponse(req, res, null, 400, "Quote is being processed.");
-			return;
-		}
-	}
-
-	// see if token still accepted
-	const paymentToken = getToken(quote.chainId, quote.tokenAddress);
-	if(!paymentToken) {
-		errorResponse(req, res, null, 400, "Payment token no longer accepted.");
-		return;
-	}
-
-	// Get providerUri from environment, fallback to tokens.providerUrl
-	const acceptedPayments = process.env.ACCEPTED_PAYMENTS.split(",");
-	const nodeRpcUris = process.env.NODE_RPC_URIS.split(",");
-	const jsonRpcUri = nodeRpcUris[acceptedPayments.indexOf(paymentToken.bundlrName)];
-	let providerUri;
-	if(jsonRpcUri === "default") {
-		console.log(`Using "default" provider url from tokens.js = ${paymentToken.providerUrl}`);
-		providerUri = paymentToken.providerUrl;
-	}
-	else {
-		console.log(`Using provider url from envvar NODE_RPC_URIS = ${jsonRpcUri}`);
-		providerUri = jsonRpcUri;
-	}
-
-	// Create Bundlr instance
-	let bundlr;
-	try {
-		const bundlrConfig = { providerUrl: providerUri };
-		bundlr = new Bundlr.default(process.env.BUNDLR_URI, paymentToken.bundlrName, process.env.PRIVATE_KEY, bundlrConfig);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, "Could not establish connection to payment processor.");
-		return;
-	}
-
-	// check if new price is sufficient
-	let bundlrPriceWei;
-	let priceWei;
-	try {
-		console.log('get quote from bundlr')
-		bundlrPriceWei = await bundlr.getPrice(quote.size)
-		priceWei = ethers.BigNumber.from(bundlrPriceWei.toString(10));
-		console.log(`bundlr quote PriceWei = ${bundlrPriceWei}`);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, "Could not query price from payment processor.");
-		return;
-	}
-	const quoteTokenAmount = ethers.BigNumber.from(quote.tokenAmount);
-	if(priceWei.gte(quoteTokenAmount)) {
-		errorResponse(req, res, null, 400, `Quoted tokenAmount is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}`);
-		return;
-	}
-
-	// Create provider
-	let provider;
-	try {
-		console.log('create provider')
-		provider = ethers.getDefaultProvider(providerUri);
-		console.log(`network = ${JSON.stringify(await provider.getNetwork())}`);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, `Error occurred while establishing connection to Node RPC provider`);
-		return;
-	}
-
-	// Create wallet
-	let wallet;
-	try {
-		wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, `Error occurred while creating a Wallet instance.`);
-		return;
-	}
-
-	// Create payment token contract handle
-	let token;
-	try {
-		const abi = [
-			'function transferFrom(address from, address to, uint256 value) external returns (bool)',
-			'function allowance(address owner, address spender) external view returns (uint256)',
-			'function balanceOf(address owner) external view returns (uint256)',
-			'function deposit(uint256 value) external',
-			'function withdraw(uint256 value) external',
-			'function transfer(address to, uint256 value) external returns (bool)'
-		];
-		const tokenAddress = paymentToken.tokenAddress;
-		token = new ethers.Contract(tokenAddress, abi, wallet);
-		console.log(`payment token address = ${token.address}`);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, `Error occurred while connecting to payment token contract.`);
-		return;
-	}
-
-	// Check allowance
-	let allowance;
-	try {
-		console.log('check allowance')
-		allowance = await token.allowance(userAddress, wallet.address);
-		console.log(`allowance = ${allowance}`);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, `Error occured while checking allowance.`);
-		return;
-	}
-	if(allowance.lt(priceWei)) {
-		errorResponse(req, res, null, 400, `Allowance is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}, allowance: ${allowance}`);
-		return;
-	}
-
-	// Check that user has sufficient funds
-	let userBalance;
-	try {
-		console.log('Check that user has sufficient funds')
-		userBalance = await token.balanceOf(userAddress);
-		console.log(`userBalance = ${userBalance}`);
-	}
-	catch(err) {
-		errorResponse(req, res, err, 500, `Error occurred while checking user token balance.`);
-		return;
-	}
-	if(userBalance.lt(priceWei)) {
-		errorResponse(req, res, null, 400, `User balance is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}, userBalance: ${userBalance}`);
-		return;
-	}
-
-	// send 200
-	console.log(`${req.path} response: 200`);
-	res.send(null);
-
-	// change status
-	try {
-		Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_START);
-	}
-	catch(err) {
-		console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_START: ${err?.name}: ${err?.message}`);
-		return;
-	}
-
-	// Fetch Gas price
-	let feePerGas;
-	let priorityFeePerGas;
-	try {
-		console.log('Fetch Gas price')
-		const feeHistory = await provider.getFeeData();
-		priorityFeePerGas = Number(feeHistory.maxPriorityFeePerGas?.toString() || MIN_GAS_FEE_POLYGON);
-		feePerGas = Number(feeHistory.maxFeePerGas?.toString() || MIN_GAS_FEE_POLYGON);
-
-		// Check gas fees are above minimum
-		priorityFeePerGas = Math.max(priorityFeePerGas, MIN_GAS_FEE_POLYGON);
-		feePerGas = Math.max(feePerGas, MIN_GAS_FEE_POLYGON);
-		console.log(`priorityFeePerGas = ${priorityFeePerGas}`);
-		console.log(`feePerGas = ${feePerGas}`);
-	} catch(err) {
-		console.error(`Using default gas price. Error occurred while fetching gas price: ${err?.name}: ${err?.message}`);
-		priorityFeePerGas = 300000000000 // default values
-		feePerGas = 300000000000 // default values
-		console.log(`priorityFeePerGas = ${priorityFeePerGas}`);
-		console.log(`feePerGas = ${feePerGas}`);
-	}
-
-	// Pull payment from user's account using transferFrom(userAddress, amount)
-	try {
-		console.log('token transferFrom', userAddress, wallet.address, priceWei.toString());
-
-		const txResponse = await token.transferFrom(userAddress, wallet.address, priceWei, {
-			maxPriorityFeePerGas: priorityFeePerGas,
-			maxFeePerGas: feePerGas
-		});
-		console.log(`transferFrom txResponse = ${JSON.stringify(txResponse)}`);
-	}
-	catch(err) {
-		console.error(`Error occurred while pulling payment from user address: ${err?.name}: ${err?.message}`);
-		try {
-			Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PULL_FAILED);
-		}
-		catch(err) {
-			console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PULL_FAILED: ${err?.name}: ${err?.message}`);
-		}
-		return;
-	}
-
-	try {
-		console.log('Set status QUOTE_STATUS_PAYMENT_PULL_SUCCESS')
-		Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PULL_SUCCESS);
-	}
-	catch(err) {
-		console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PULL_SUCCESS: ${err?.name}: ${err?.message}`);
-		return;
-	}
-
-
-	// Unwrap payment token (ex. WETH -> ETH)
-	try {
-		async function performWithdraw() {
-			const txResponse = await token.withdraw(priceWei, {
-				maxPriorityFeePerGas: priorityFeePerGas,
-				maxFeePerGas: feePerGas
-			});
-			console.log(`withdraw txResponse = ${JSON.stringify(txResponse)}`);
-		}
-
-		performWithdraw();
-	}
-	catch(err) {
-		console.error(`Error occurred while unwrapping payment: ${err?.name}: ${err?.message}`);
-		try {
-			Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_UNWRAP_FAILED);
-		}
-		catch(err) {
-			console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_UNWRAP_FAILED: ${err?.name}: ${err?.message}`);
-		}
-		return;
-	}
-
-	// Fund server's Bundlr Account
-	try {
-		console.log('Fund Bundlr Account')
-		await bundlr.fund(bundlrPriceWei);
-		console.log('bundlr funded successfully')
-	}
-	catch(err) {
-		console.error(`Error occurred while funding Bundlr account: ${err?.name}: ${err?.message}`);
-		try {
-			Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PUSH_FAILED);
-		}
-		catch(err) {
-			console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PUSH_FAILED: ${err?.name}: ${err?.message}}`);
-			return;
-		}
-	}
-
-	try {
-		console.log('Set status QUOTE_STATUS_UPLOAD_START')
-		Quote.setStatus(quoteId, Quote.QUOTE_STATUS_UPLOAD_START);
-	}
-	catch(err) {
-		console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_UPLOAD_START: ${err?.name}: ${err?.message}}`);
-		return;
-	}
-
-	Promise.all(files.map((file, index) => {
-		return new Promise(async (resolve, reject) => {
-			// Get quoted file length
-			let quotedFileLength;
-			try {
-				quotedFileLength = File.get(quoteId, index).length;
-			}
-			catch(err) {
-				console.error(`Error occurred while reading quoted file length from database: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`);
-				reject(Quote.QUOTE_STATUS_UPLOAD_INTERNAL_ERROR);
-				return;
-			}
-
-			const ipfsFile = process.env.IPFS_GATEWAY + file.substring(7);
-
-			// download file
-			console.log('download file')
-			await axios({
-				method: "get",
-				url: ipfsFile,
-				responseType: "arraybuffer"  // Download in chunks, stored in memory
-			})
-			.then(async res => {
-				// download started
-				const contentType = res.headers['content-type'];
-				console.log('download contentType', contentType)
-				const actualLength = parseInt(res.headers['content-length']);
-				console.log('download actualLength', actualLength)
-
-				if(actualLength) {
-					if(actualLength > quotedFileLength) {
-						console.error(`Actual file length exceeds quoted length. CID = ${file}, file index = ${index}, quoted length = ${quotedFileLength}, actual length ${actualLength}`);
-						reject(Quote.QUOTE_STATUS_UPLOAD_ACTUAL_FILE_LEN_EXCEEDS_QUOTE);
-						return;
-					}
-				}
-				else {
-					console.warn("Warning: Unknown file length. Uploading blindly.");
-				}
-
-				// Set the Arweave tags: https://github.com/ArweaveTeam/arweave-standards/blob/master/best-practices/BP-105.md
-				const arweaveTags = contentType ? [{name: "Content-Type", value: contentType}] : [];
-				console.log('arweaveTags', arweaveTags)
-
-				const uploader = bundlr.uploader.chunkedUploader;
-				console.log('process.env.BUNDLR_CHUNK_SIZE', process.env.BUNDLR_CHUNK_SIZE)
-				console.log('process.env.BUNDLR_BATCH_SIZE', process.env.BUNDLR_BATCH_SIZE)
-
-				uploader.setChunkSize(process.env.BUNDLR_CHUNK_SIZE || 524288); // Default: 512 kB
-				uploader.setBatchSize(process.env.BUNDLR_BATCH_SIZE || 1); // Default: 1 chunk at a time
-
-				uploader.on("chunkError", (e) => {
-					console.error(`Error uploading chunk number ${e.id} - ${e.res.statusText}. CID = ${file}, file index = ${index}`);
-					reject(Quote.QUOTE_STATUS_UPLOAD_UPLOAD_FAILED);
-					return;
-				});
-				uploader.on("done", async (finishRes) => {
-					const transactionId = finishRes.data.id;
-					console.log('upload done')
-					console.log('transactionId', transactionId)
-					try {
-						File.setHash(quoteId, index, transactionId);
-					}
-					catch(err) {
-						console.error(`Error occurred while writing file transaction id to database: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`);
-						reject(Quote.QUOTE_STATUS_UPLOAD_INTERNAL_ERROR);
-						return;
-					}
-
-					resolve(transactionId);
-					return;
-				});
-
-				const transactionOptions = {tags: arweaveTags};
-				try {
-					// Download each chunk and immediately upload to Bundlr without storing to disk.
-					console.log('Download each chunk and immediately upload to Bundlr without storing to disk.')
-					await uploader.uploadData(Buffer.from(res.data, "binary"), transactionOptions);
-					console.log('uploader.uploadData complete')
-				}
-				catch(err) {
-					console.error(`Error occurred while uploading file: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`);
-					// TODO: Consider separate status for insufficient funds.
-					reject(Quote.QUOTE_STATUS_UPLOAD_UPLOAD_FAILED);
-					return;
-				}
-			})
-			.catch(err => {
-				console.error(`Error occurred while downloading file ${file}, index ${index}: ${err?.name}: ${err?.message}`);
-				reject(Quote.QUOTE_STATUS_UPLOAD_DOWNLOAD_FAILED);
-				return;
-			});
-		});
-	})).then(() => {
-		try {
-			console.log('Set status QUOTE_STATUS_UPLOAD_END')
-			Quote.setStatus(quoteId, Quote.QUOTE_STATUS_UPLOAD_END);
-		}
-		catch(err) {
-			console.error(`Error occurred while setting status to Quote.QUOTE_STATUS_UPLOAD_END: ${err?.name}: ${err?.message}}`);
-			return;
-		}
-	}).catch(quoteStatus => {
-		try {
-			Quote.setStatus(quoteId, quoteStatus);
-		}
-		catch(err) {
-			console.error(`Error occurred while setting status to ${quoteStatus}: ${err?.name}: ${err?.message}}`);
-			return;
-		}
-	});
-};
+  console.log(`upload request: ${JSON.stringify(req.body)}`)
+
+  // Validate request
+  if (!req.body) {
+    errorResponse(req, res, null, 400, 'Content can not be empty!')
+    return
+  }
+
+  // validate fields
+  const quoteId = req.body.quoteId
+  if (typeof quoteId === 'undefined') {
+    errorResponse(req, res, null, 400, 'Missing quoteId.')
+    return
+  }
+  if (typeof quoteId !== 'string') {
+    errorResponse(req, res, null, 400, 'Invalid quoteId.')
+    return
+  }
+
+  const files = typeof req.body.files === 'string' ? [req.body.files] : req.body.files
+  if (typeof files === 'undefined') {
+    errorResponse(req, res, null, 400, 'Missing files field.')
+    return
+  }
+  if (typeof files !== 'object' || !Array.isArray(files)) {
+    errorResponse(req, res, null, 400, 'Invalid files field.')
+    return
+  }
+  if (files.length == 0) {
+    errorResponse(req, res, null, 400, 'Empty files field.')
+    return
+  }
+
+  if (files.length > 64) {
+    errorResponse(req, res, null, 400, 'Too many files. Max 64.')
+    return
+  }
+
+  const cidRegex =
+    /^(Qm[1-9A-HJ-NP-Za-km-z]{44,}|b[A-Za-z2-7]{58,}|B[A-Z2-7]{58,}|z[1-9A-HJ-NP-Za-km-z]{48,}|F[0-9A-F]{50,})$/i
+  for (let i = 0; i < files.length; i++) {
+    if (typeof files[i] !== 'string') {
+      errorResponse(req, res, null, 400, `Invalid files field on index ${i}.`)
+      return
+    }
+    // TODO: validate URL format better
+    if (!files[i].startsWith('ipfs://')) {
+      errorResponse(
+        req,
+        res,
+        null,
+        400,
+        `Invalid protocol on index ${i}. Must be ipfs://<CID>`
+      )
+      return
+    }
+    if (!cidRegex.test(files[i].substring(7))) {
+      errorResponse(req, res, null, 400, `Invalid CID on index ${i}.`)
+      return
+    }
+  }
+
+  if (typeof req.body.nonce === 'undefined') {
+    errorResponse(req, res, null, 400, 'Missing nonce.')
+    return
+  }
+
+  const nonce = Number(req.body.nonce)
+
+  if (isNaN(nonce)) {
+    errorResponse(req, res, null, 400, 'Invalid nonce.')
+    return
+  }
+
+  const signature = req.body.signature
+  if (typeof signature === 'undefined') {
+    errorResponse(req, res, null, 400, 'Missing signature.')
+    return
+  }
+  if (typeof signature !== 'string') {
+    errorResponse(req, res, null, 400, 'Invalid signature.')
+    return
+  }
+
+  // validate quote
+  let quote
+  try {
+    quote = Quote.get(quoteId)
+    if (quote == undefined) {
+      errorResponse(req, res, null, 404, 'Quote not found.')
+      return
+    }
+  } catch (err) {
+    errorResponse(req, res, err, 500, 'Error occurred while validating quote.')
+    return
+  }
+
+  const userAddress = quote.userAddress
+  const message = ethers.utils.sha256(
+    ethers.utils.toUtf8Bytes(quoteId + nonce.toString())
+  )
+  let signerAddress
+  try {
+    signerAddress = ethers.utils.verifyMessage(message, signature)
+  } catch (err) {
+    errorResponse(req, res, err, 403, 'Invalid signature.')
+    return
+  }
+
+  if (signerAddress != userAddress) {
+    errorResponse(req, res, null, 403, 'Invalid signature.')
+    return
+  }
+
+  let oldNonce
+  try {
+    oldNonce = Nonce.get(userAddress)?.nonce || 0.0
+  } catch (err) {
+    errorResponse(req, res, err, 500, 'Error occurred while validating nonce.')
+    return
+  }
+  if (parseFloat(nonce) <= parseFloat(oldNonce)) {
+    errorResponse(req, res, null, 403, 'Invalid nonce.')
+    return
+  }
+  try {
+    Nonce.set(userAddress, nonce)
+  } catch (err) {
+    errorResponse(req, res, err, 500, 'Error occurred while storing nonce.')
+    return
+  }
+
+  // check status of quote
+  if (quote.status != Quote.QUOTE_STATUS_WAITING) {
+    if (quote.status == Quote.QUOTE_STATUS_UPLOAD_END) {
+      errorResponse(req, res, null, 400, 'Quote has been completed.')
+      return
+    } else {
+      errorResponse(req, res, null, 400, 'Quote is being processed.')
+      return
+    }
+  }
+
+  // see if token still accepted
+  const paymentToken = getToken(quote.chainId, quote.tokenAddress)
+  if (!paymentToken) {
+    errorResponse(req, res, null, 400, 'Payment token no longer accepted.')
+    return
+  }
+
+  // Get providerUri from environment, fallback to tokens.providerUrl
+  const acceptedPayments = process.env.ACCEPTED_PAYMENTS.split(',')
+  const nodeRpcUris = process.env.NODE_RPC_URIS.split(',')
+  const jsonRpcUri = nodeRpcUris[acceptedPayments.indexOf(paymentToken.bundlrName)]
+  let providerUri
+  if (jsonRpcUri === 'default') {
+    console.log(
+      `Using "default" provider url from tokens.js = ${paymentToken.providerUrl}`
+    )
+    providerUri = paymentToken.providerUrl
+  } else {
+    console.log(`Using provider url from envvar NODE_RPC_URIS = ${jsonRpcUri}`)
+    providerUri = jsonRpcUri
+  }
+
+  // Create Bundlr instance
+  let bundlr
+  try {
+    const bundlrConfig = { providerUrl: providerUri }
+    bundlr = new Bundlr.default(
+      process.env.BUNDLR_URI,
+      paymentToken.bundlrName,
+      process.env.PRIVATE_KEY,
+      bundlrConfig
+    )
+  } catch (err) {
+    errorResponse(
+      req,
+      res,
+      err,
+      500,
+      'Could not establish connection to payment processor.'
+    )
+    return
+  }
+
+  // check if new price is sufficient
+  let bundlrPriceWei
+  let priceWei
+  try {
+    console.log('get quote from bundlr')
+    bundlrPriceWei = await bundlr.getPrice(quote.size)
+    priceWei = ethers.BigNumber.from(bundlrPriceWei.toString(10))
+    console.log(`bundlr quote PriceWei = ${bundlrPriceWei}`)
+  } catch (err) {
+    errorResponse(req, res, err, 500, 'Could not query price from payment processor.')
+    return
+  }
+  const quoteTokenAmount = ethers.BigNumber.from(quote.tokenAmount)
+  if (priceWei.gte(quoteTokenAmount)) {
+    errorResponse(
+      req,
+      res,
+      null,
+      400,
+      `Quoted tokenAmount is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}`
+    )
+    return
+  }
+
+  // Create provider
+  let provider
+  try {
+    console.log('create provider')
+    provider = ethers.getDefaultProvider(providerUri)
+    console.log(`network = ${JSON.stringify(await provider.getNetwork())}`)
+  } catch (err) {
+    errorResponse(
+      req,
+      res,
+      err,
+      500,
+      `Error occurred while establishing connection to Node RPC provider`
+    )
+    return
+  }
+
+  // Create wallet
+  let wallet
+  try {
+    wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider)
+  } catch (err) {
+    errorResponse(req, res, err, 500, `Error occurred while creating a Wallet instance.`)
+    return
+  }
+
+  // Create payment token contract handle
+  let token
+  try {
+    const abi = [
+      'function transferFrom(address from, address to, uint256 value) external returns (bool)',
+      'function allowance(address owner, address spender) external view returns (uint256)',
+      'function balanceOf(address owner) external view returns (uint256)',
+      'function deposit(uint256 value) external',
+      'function withdraw(uint256 value) external',
+      'function transfer(address to, uint256 value) external returns (bool)'
+    ]
+    const tokenAddress = paymentToken.tokenAddress
+    token = new ethers.Contract(tokenAddress, abi, wallet)
+    console.log(`payment token address = ${token.address}`)
+  } catch (err) {
+    errorResponse(
+      req,
+      res,
+      err,
+      500,
+      `Error occurred while connecting to payment token contract.`
+    )
+    return
+  }
+
+  // Check allowance
+  let allowance
+  try {
+    console.log('check allowance')
+    allowance = await token.allowance(userAddress, wallet.address)
+    console.log(`allowance = ${allowance}`)
+  } catch (err) {
+    errorResponse(req, res, err, 500, `Error occured while checking allowance.`)
+    return
+  }
+  if (allowance.lt(priceWei)) {
+    errorResponse(
+      req,
+      res,
+      null,
+      400,
+      `Allowance is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}, allowance: ${allowance}`
+    )
+    return
+  }
+
+  // Check that user has sufficient funds
+  let userBalance
+  try {
+    console.log('Check that user has sufficient funds')
+    userBalance = await token.balanceOf(userAddress)
+    console.log(`userBalance = ${userBalance}`)
+  } catch (err) {
+    errorResponse(req, res, err, 500, `Error occurred while checking user token balance.`)
+    return
+  }
+  if (userBalance.lt(priceWei)) {
+    errorResponse(
+      req,
+      res,
+      null,
+      400,
+      `User balance is less than current rate. Quoted amount: ${quote.tokenAmount}, current rate: ${priceWei}, userBalance: ${userBalance}`
+    )
+    return
+  }
+
+  // send 200
+  console.log(`${req.path} response: 200`)
+  res.send(null)
+
+  // change status
+  try {
+    Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_START)
+  } catch (err) {
+    console.error(
+      `Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_START: ${err?.name}: ${err?.message}`
+    )
+    return
+  }
+
+  // Fetch Gas price
+  let feePerGas
+  let priorityFeePerGas
+  try {
+    console.log('Fetch Gas price')
+    const feeHistory = await provider.getFeeData()
+    priorityFeePerGas = Number(
+      feeHistory.maxPriorityFeePerGas?.toString() || MIN_GAS_FEE_POLYGON
+    )
+    feePerGas = Number(feeHistory.maxFeePerGas?.toString() || MIN_GAS_FEE_POLYGON)
+
+    // Check gas fees are above minimum
+    priorityFeePerGas = Math.max(priorityFeePerGas, MIN_GAS_FEE_POLYGON)
+    feePerGas = Math.max(feePerGas, MIN_GAS_FEE_POLYGON)
+    console.log(`priorityFeePerGas = ${priorityFeePerGas}`)
+    console.log(`feePerGas = ${feePerGas}`)
+  } catch (err) {
+    console.error(
+      `Using default gas price. Error occurred while fetching gas price: ${err?.name}: ${err?.message}`
+    )
+    priorityFeePerGas = 300000000000 // default values
+    feePerGas = 300000000000 // default values
+    console.log(`priorityFeePerGas = ${priorityFeePerGas}`)
+    console.log(`feePerGas = ${feePerGas}`)
+  }
+
+  // Pull payment from user's account using transferFrom(userAddress, amount)
+  try {
+    console.log('token transferFrom', userAddress, wallet.address, priceWei.toString())
+
+    const txResponse = await token.transferFrom(userAddress, wallet.address, priceWei, {
+      maxPriorityFeePerGas: priorityFeePerGas,
+      maxFeePerGas: feePerGas
+    })
+    console.log(`transferFrom txResponse = ${JSON.stringify(txResponse)}`)
+  } catch (err) {
+    console.error(
+      `Error occurred while pulling payment from user address: ${err?.name}: ${err?.message}`
+    )
+    try {
+      Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PULL_FAILED)
+    } catch (err) {
+      console.error(
+        `Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PULL_FAILED: ${err?.name}: ${err?.message}`
+      )
+    }
+    return
+  }
+
+  try {
+    console.log('Set status QUOTE_STATUS_PAYMENT_PULL_SUCCESS')
+    Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PULL_SUCCESS)
+  } catch (err) {
+    console.error(
+      `Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PULL_SUCCESS: ${err?.name}: ${err?.message}`
+    )
+    return
+  }
+
+  // Fund server's Bundlr Account
+  try {
+    console.log('Fund Bundlr Account')
+    await bundlr.fund(bundlrPriceWei)
+    console.log('bundlr funded successfully')
+  } catch (err) {
+    console.error(
+      `Error occurred while funding Bundlr account: ${err?.name}: ${err?.message}`
+    )
+    try {
+      Quote.setStatus(quoteId, Quote.QUOTE_STATUS_PAYMENT_PUSH_FAILED)
+    } catch (err) {
+      console.error(
+        `Error occurred while setting status to Quote.QUOTE_STATUS_PAYMENT_PUSH_FAILED: ${err?.name}: ${err?.message}}`
+      )
+      return
+    }
+  }
+
+  try {
+    console.log('Set status QUOTE_STATUS_UPLOAD_START')
+    Quote.setStatus(quoteId, Quote.QUOTE_STATUS_UPLOAD_START)
+  } catch (err) {
+    console.error(
+      `Error occurred while setting status to Quote.QUOTE_STATUS_UPLOAD_START: ${err?.name}: ${err?.message}}`
+    )
+    return
+  }
+
+  Promise.all(
+    files.map((file, index) => {
+      return new Promise(async (resolve, reject) => {
+        // Get quoted file length
+        let quotedFileLength
+        try {
+          quotedFileLength = File.get(quoteId, index).length
+        } catch (err) {
+          console.error(
+            `Error occurred while reading quoted file length from database: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`
+          )
+          reject(Quote.QUOTE_STATUS_UPLOAD_INTERNAL_ERROR)
+          return
+        }
+
+        const ipfsFile = process.env.IPFS_GATEWAY + file.substring(7)
+
+        // download file
+        console.log('download file')
+        await axios({
+          method: 'get',
+          url: ipfsFile,
+          responseType: 'arraybuffer' // Download in chunks, stored in memory
+        })
+          .then(async (res) => {
+            // download started
+            const contentType = res.headers['content-type']
+            console.log('download contentType', contentType)
+            const actualLength = parseInt(res.headers['content-length'])
+            console.log('download actualLength', actualLength)
+
+            if (actualLength) {
+              if (actualLength > quotedFileLength) {
+                console.error(
+                  `Actual file length exceeds quoted length. CID = ${file}, file index = ${index}, quoted length = ${quotedFileLength}, actual length ${actualLength}`
+                )
+                reject(Quote.QUOTE_STATUS_UPLOAD_ACTUAL_FILE_LEN_EXCEEDS_QUOTE)
+                return
+              }
+            } else {
+              console.warn('Warning: Unknown file length. Uploading blindly.')
+            }
+
+            // Set the Arweave tags: https://github.com/ArweaveTeam/arweave-standards/blob/master/best-practices/BP-105.md
+            const arweaveTags = contentType
+              ? [{ name: 'Content-Type', value: contentType }]
+              : []
+            console.log('arweaveTags', arweaveTags)
+
+            const uploader = bundlr.uploader.chunkedUploader
+            console.log('process.env.BUNDLR_CHUNK_SIZE', process.env.BUNDLR_CHUNK_SIZE)
+            console.log('process.env.BUNDLR_BATCH_SIZE', process.env.BUNDLR_BATCH_SIZE)
+
+            uploader.setChunkSize(process.env.BUNDLR_CHUNK_SIZE || 524288) // Default: 512 kB
+            uploader.setBatchSize(process.env.BUNDLR_BATCH_SIZE || 1) // Default: 1 chunk at a time
+
+            uploader.on('chunkError', (e) => {
+              console.error(
+                `Error uploading chunk number ${e.id} - ${e.res.statusText}. CID = ${file}, file index = ${index}`
+              )
+              reject(Quote.QUOTE_STATUS_UPLOAD_UPLOAD_FAILED)
+              return
+            })
+            uploader.on('done', async (finishRes) => {
+              const transactionId = finishRes.data.id
+              console.log('upload done')
+              console.log('transactionId', transactionId)
+              try {
+                File.setHash(quoteId, index, transactionId)
+              } catch (err) {
+                console.error(
+                  `Error occurred while writing file transaction id to database: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`
+                )
+                reject(Quote.QUOTE_STATUS_UPLOAD_INTERNAL_ERROR)
+                return
+              }
+
+              resolve(transactionId)
+              return
+            })
+
+            const transactionOptions = { tags: arweaveTags }
+            try {
+              // Download each chunk and immediately upload to Bundlr without storing to disk.
+              console.log(
+                'Download each chunk and immediately upload to Bundlr without storing to disk.'
+              )
+              await uploader.uploadData(
+                Buffer.from(res.data, 'binary'),
+                transactionOptions
+              )
+              console.log('uploader.uploadData complete')
+            } catch (err) {
+              console.error(
+                `Error occurred while uploading file: ${err?.name}: ${err?.message}. CID = ${file}, file index = ${index}`
+              )
+              // TODO: Consider separate status for insufficient funds.
+              reject(Quote.QUOTE_STATUS_UPLOAD_UPLOAD_FAILED)
+              return
+            }
+          })
+          .catch((err) => {
+            console.error(
+              `Error occurred while downloading file ${file}, index ${index}: ${err?.name}: ${err?.message}`
+            )
+            reject(Quote.QUOTE_STATUS_UPLOAD_DOWNLOAD_FAILED)
+            return
+          })
+      })
+    })
+  )
+    .then(() => {
+      try {
+        console.log('Set status QUOTE_STATUS_UPLOAD_END')
+        Quote.setStatus(quoteId, Quote.QUOTE_STATUS_UPLOAD_END)
+        // Unwrap payment token (ex. WETH -> ETH)
+      } catch (err) {
+        console.error(
+          `Error occurred while setting status to Quote.QUOTE_STATUS_UPLOAD_END: ${err?.name}: ${err?.message}}`
+        )
+        return
+      }
+      try {
+        async function performWithdraw() {
+          console.log('withdraw WMATIC into Matic')
+          const txResponse = await token.withdraw(priceWei, {
+            maxPriorityFeePerGas: priorityFeePerGas,
+            maxFeePerGas: feePerGas
+          })
+          console.log(`withdraw success txResponse = ${JSON.stringify(txResponse)}`)
+        }
+
+        performWithdraw()
+      } catch (err) {
+        console.error(
+          `Error occurred while unwrapping payment: ${err?.name}: ${err?.message}`
+        )
+        return
+      }
+    })
+    .catch((quoteStatus) => {
+      try {
+        Quote.setStatus(quoteId, quoteStatus)
+      } catch (err) {
+        console.error(
+          `Error occurred while setting status to ${quoteStatus}: ${err?.name}: ${err?.message}}`
+        )
+        return
+      }
+    })
+}