diff --git a/src/index.js b/src/index.js
index 4f86cb80..1c7d8079 100644
--- a/src/index.js
+++ b/src/index.js
@@ -8,6 +8,7 @@ import { makeCurrencyconverterapiPlugin } from './rate/currencyconverterapi.js'
 import { makeNomicsPlugin } from './rate/nomics.js'
 import { makeXagauPlugin } from './rate/xagau.js'
 import { makeChangellyPlugin } from './swap/changelly.js'
+import { makeSideShiftPlugin } from './swap/sideshift'
 import { makeChangeNowPlugin } from './swap/changenow.js'
 import { makeCoinSwitchPlugin } from './swap/coinswitch.js'
 import { makeFaastPlugin } from './swap/faast.js'
@@ -29,6 +30,7 @@ const edgeCorePlugins = {
 
   // Swap plugins:
   changelly: makeChangellyPlugin,
+  sideshift: makeSideShiftPlugin,
   changenow: makeChangeNowPlugin,
   coinswitch: makeCoinSwitchPlugin,
   faast: makeFaastPlugin,
diff --git a/src/swap/sideshift.js b/src/swap/sideshift.js
new file mode 100644
index 00000000..4b6653c7
--- /dev/null
+++ b/src/swap/sideshift.js
@@ -0,0 +1,447 @@
+// @flow
+
+import { gt, lt, mul } from 'biggystring'
+import {
+  type EdgeCorePluginOptions,
+  type EdgeCurrencyWallet,
+  type EdgeSwapInfo,
+  type EdgeSwapPlugin,
+  type EdgeSwapQuote,
+  type EdgeSwapRequest,
+  type EdgeTransaction,
+  SwapAboveLimitError,
+  SwapBelowLimitError,
+  SwapCurrencyError
+} from 'edge-core-js/types'
+
+import { makeSwapPluginQuote } from '../swap-helpers.js'
+
+const INVALID_CURRENCY_CODES = {}
+
+// Invalid currency codes should *not* have transcribed codes
+// because currency codes with transcribed versions are NOT invalid
+const CURRENCY_CODE_TRANSCRIPTION = {
+  // Edge currencyCode: exchangeCurrencyCode
+  USDT: 'USDT20'
+}
+
+const swapInfo: EdgeSwapInfo = {
+  pluginId: 'sideshift',
+  displayName: 'SideShift',
+
+  supportEmail: 'support@sideshift.ai'
+}
+
+const uri = 'https://staging.sideshift.ai/changelly-api'
+const expirationMs = 1000 * 60 * 20
+const expirationFixedMs = 1000 * 60 * 5
+type QuoteInfo = {
+  id: string,
+  apiExtraFee: string,
+  changellyFee: string,
+  payinExtraId: string | null,
+  payoutExtraId: string | null,
+  amountExpectedFrom: number,
+  status: string,
+  currencyFrom: string,
+  currencyTo: string,
+  amountTo: number,
+  payinAddress: string,
+  payoutAddress: string,
+  createdAt: string
+}
+type FixedQuoteInfo = {
+  id: string,
+  amountExpectedFrom: string,
+  amountExpectedTo: string,
+  amountTo: number,
+  apiExtraFee: string,
+  changellyFee: string,
+  createdAt: string,
+  currencyFrom: string,
+  currencyTo: string,
+  kycRequired: boolean,
+  payinAddress: string,
+  payinExtraId: string | null,
+  payoutAddress: string,
+  payoutExtraId: string | null,
+  refundAddress: string,
+  refundExtraId: string | null,
+  status: string
+}
+
+const dontUseLegacy = {
+  DGB: true
+}
+
+async function getAddress(
+  wallet: EdgeCurrencyWallet,
+  currencyCode: string
+): Promise<string> {
+  const addressInfo = await wallet.getReceiveAddress({ currencyCode })
+  return addressInfo.legacyAddress && !dontUseLegacy[currencyCode]
+    ? addressInfo.legacyAddress
+    : addressInfo.publicAddress
+}
+
+function checkReply(reply: Object, request: EdgeSwapRequest) {
+  if (reply.error != null) {
+    if (
+      reply.error.code === -32602 ||
+      /Invalid currency:/.test(reply.error.message)
+    ) {
+      throw new SwapCurrencyError(
+        swapInfo,
+        request.fromCurrencyCode,
+        request.toCurrencyCode
+      )
+    }
+    throw new Error('SideShift error: ' + JSON.stringify(reply.error))
+  }
+}
+
+export function makeSideShiftPlugin(
+  opts: EdgeCorePluginOptions
+): EdgeSwapPlugin {
+  const { initOptions, io, log } = opts
+
+  if (initOptions.apiKey == null || initOptions.secret == null) {
+    throw new Error('No SideShift apiKey or secret provided.')
+  }
+
+  async function call(json: any) {
+    const body = JSON.stringify(json)
+
+    const headers = {
+      'Content-Type': 'application/json'
+    }
+    const response = await io.fetch(uri, { method: 'POST', body, headers })
+
+    if (!response.ok) {
+      throw new Error(`SideShift returned error code ${response.status}`)
+    }
+    return response.json()
+  }
+
+  const out: EdgeSwapPlugin = {
+    swapInfo,
+    async fetchSwapQuote(
+      request: EdgeSwapRequest,
+      userSettings: Object | void
+    ): Promise<EdgeSwapQuote> {
+      if (
+        // if either currencyCode is invalid *and* doesn't have a transcription
+        INVALID_CURRENCY_CODES[request.fromCurrencyCode] ||
+        INVALID_CURRENCY_CODES[request.toCurrencyCode]
+      ) {
+        throw new SwapCurrencyError(
+          swapInfo,
+          request.fromCurrencyCode,
+          request.toCurrencyCode
+        )
+      }
+
+      // Non-fixed-rate:
+      const estimatePromise = this.getEstimate(request, userSettings)
+      const estimateResult = await estimatePromise
+      return estimateResult
+
+      // For Fixed-Rate (SideShift ToDo):
+      // const fixedPromise = this.getFixedQuote(request, userSettings)
+      // const estimatePromise = this.getEstimate(request, userSettings)
+      // try {
+      //   const fixedResult = await fixedPromise
+      //   return fixedResult
+      // } catch (e) {
+      //   const estimateResult = await estimatePromise
+      //   return estimateResult
+      // }
+    },
+
+    async getFixedQuote(
+      request: EdgeSwapRequest,
+      userSettings: Object | void
+    ): Promise<EdgeSwapQuote> {
+      const [fromAddress, toAddress] = await Promise.all([
+        getAddress(request.fromWallet, request.fromCurrencyCode),
+        getAddress(request.toWallet, request.toCurrencyCode)
+      ])
+      const quoteAmount =
+        request.quoteFor === 'from'
+          ? await request.fromWallet.nativeToDenomination(
+              request.nativeAmount,
+              request.fromCurrencyCode
+            )
+          : await request.toWallet.nativeToDenomination(
+              request.nativeAmount,
+              request.toCurrencyCode
+            )
+
+      let safeFromCurrencyCode = request.fromCurrencyCode
+      let safeToCurrencyCode = request.toCurrencyCode
+      if (CURRENCY_CODE_TRANSCRIPTION[request.fromCurrencyCode]) {
+        safeFromCurrencyCode =
+          CURRENCY_CODE_TRANSCRIPTION[request.fromCurrencyCode]
+      }
+      if (CURRENCY_CODE_TRANSCRIPTION[request.toCurrencyCode]) {
+        safeToCurrencyCode = CURRENCY_CODE_TRANSCRIPTION[request.toCurrencyCode]
+      }
+      safeFromCurrencyCode = safeFromCurrencyCode.toLowerCase()
+      safeToCurrencyCode = safeToCurrencyCode.toLowerCase()
+      const fixedRateQuote = await call({
+        jsonrpc: '2.0',
+        id: 'one',
+        method: 'getFixRate',
+        params: {
+          from: safeFromCurrencyCode,
+          to: safeToCurrencyCode
+        }
+      })
+      const min =
+        request.quoteFor === 'from'
+          ? fixedRateQuote.result.minFrom
+          : fixedRateQuote.result.minTo
+      const max =
+        request.quoteFor === 'from'
+          ? fixedRateQuote.result.maxFrom
+          : fixedRateQuote.result.maxTo
+      const nativeMin = await request.fromWallet.denominationToNative(
+        min,
+        request.fromCurrencyCode
+      )
+      const nativeMax = await request.fromWallet.denominationToNative(
+        max,
+        request.fromCurrencyCode
+      )
+      if (lt(request.nativeAmount, nativeMin)) {
+        throw new SwapBelowLimitError(swapInfo, nativeMin)
+      }
+      if (gt(request.nativeAmount, nativeMax)) {
+        throw new SwapAboveLimitError(swapInfo, nativeMax)
+      }
+      const params =
+        request.quoteFor === 'from'
+          ? {
+              amount: quoteAmount,
+              from: safeFromCurrencyCode,
+              to: safeToCurrencyCode,
+              address: toAddress,
+              extraId: null,
+              refundAddress: fromAddress,
+              refundExtraId: null,
+              rateId: fixedRateQuote.result.id
+            }
+          : {
+              amountTo: quoteAmount,
+              from: safeFromCurrencyCode,
+              to: safeToCurrencyCode,
+              address: toAddress,
+              extraId: null,
+              refundAddress: fromAddress,
+              refundExtraId: null,
+              rateId: fixedRateQuote.result.id
+            }
+
+      const sendReply = await call({
+        jsonrpc: '2.0',
+        id: 2,
+        method: 'createFixTransaction',
+        params
+      })
+      checkReply(sendReply, request)
+      const quoteInfo: FixedQuoteInfo = sendReply.result
+      const spendInfoAmount = await request.fromWallet.denominationToNative(
+        quoteInfo.amountExpectedFrom,
+        // need to verify that this is okay
+        // why use currencyCode from quoteInfo in the first place?
+        request.fromCurrencyCode.toUpperCase()
+      )
+
+      const spendInfo = {
+        currencyCode: request.fromCurrencyCode,
+        spendTargets: [
+          {
+            nativeAmount: spendInfoAmount,
+            publicAddress: quoteInfo.payinAddress,
+            otherParams: {
+              uniqueIdentifier: quoteInfo.payinExtraId
+            }
+          }
+        ]
+      }
+      const tx: EdgeTransaction = await request.fromWallet.makeSpend(spendInfo)
+      if (tx.otherParams == null) tx.otherParams = {}
+      tx.otherParams.payinAddress = spendInfo.spendTargets[0].publicAddress
+      tx.otherParams.uniqueIdentifier =
+        spendInfo.spendTargets[0].otherParams.uniqueIdentifier
+
+      const amountExpectedFromNative = await request.fromWallet.denominationToNative(
+        sendReply.result.amountExpectedFrom,
+        request.fromCurrencyCode
+      )
+      const amountExpectedToTo = await request.fromWallet.denominationToNative(
+        sendReply.result.amountExpectedTo,
+        request.toCurrencyCode
+      )
+      return makeSwapPluginQuote(
+        request,
+        amountExpectedFromNative,
+        amountExpectedToTo,
+        tx,
+        toAddress,
+        'sideshift',
+        false,
+        new Date(Date.now() + expirationFixedMs),
+        quoteInfo.id
+      )
+    },
+
+    async getEstimate(
+      request: EdgeSwapRequest,
+      userSettings: Object | void
+    ): Promise<EdgeSwapQuote> {
+      // Grab addresses:
+      const [fromAddress, toAddress] = await Promise.all([
+        getAddress(request.fromWallet, request.fromCurrencyCode),
+        getAddress(request.toWallet, request.toCurrencyCode)
+      ])
+
+      // Convert the native amount to a denomination:
+      const quoteAmount =
+        request.quoteFor === 'from'
+          ? await request.fromWallet.nativeToDenomination(
+              request.nativeAmount,
+              request.fromCurrencyCode
+            )
+          : await request.toWallet.nativeToDenomination(
+              request.nativeAmount,
+              request.toCurrencyCode
+            )
+
+      let safeFromCurrencyCode = request.fromCurrencyCode
+      let safeToCurrencyCode = request.toCurrencyCode
+      if (CURRENCY_CODE_TRANSCRIPTION[request.fromCurrencyCode]) {
+        safeFromCurrencyCode =
+          CURRENCY_CODE_TRANSCRIPTION[request.fromCurrencyCode]
+      }
+      if (CURRENCY_CODE_TRANSCRIPTION[request.toCurrencyCode]) {
+        safeToCurrencyCode = CURRENCY_CODE_TRANSCRIPTION[request.toCurrencyCode]
+      }
+      safeFromCurrencyCode = safeFromCurrencyCode.toLowerCase()
+      safeToCurrencyCode = safeToCurrencyCode.toLowerCase()
+      // Swap the currencies if we need a reverse quote:
+      const quoteParams =
+        request.quoteFor === 'from'
+          ? {
+              from: safeFromCurrencyCode,
+              to: safeToCurrencyCode,
+              amount: quoteAmount
+            }
+          : {
+              from: safeToCurrencyCode,
+              to: safeFromCurrencyCode,
+              amount: quoteAmount
+            }
+
+      // Get the estimate from the server:
+      const quoteReplies = await Promise.all([
+        call({
+          jsonrpc: '2.0',
+          id: 'one',
+          method: 'getMinAmount',
+          params: {
+            from: safeFromCurrencyCode,
+            to: safeToCurrencyCode
+          }
+        }),
+        call({
+          jsonrpc: '2.0',
+          id: 'two',
+          method: 'getExchangeAmount',
+          params: quoteParams
+        })
+      ])
+      checkReply(quoteReplies[0], request)
+      checkReply(quoteReplies[1], request)
+
+      // Calculate the amounts:
+      let fromAmount, fromNativeAmount, toNativeAmount
+      if (request.quoteFor === 'from') {
+        fromAmount = quoteAmount
+        fromNativeAmount = request.nativeAmount
+        toNativeAmount = await request.toWallet.denominationToNative(
+          quoteReplies[1].result,
+          request.toCurrencyCode
+        )
+      } else {
+        fromAmount = mul(quoteReplies[1].result, '1.02')
+        fromNativeAmount = await request.fromWallet.denominationToNative(
+          fromAmount,
+          request.fromCurrencyCode
+        )
+        toNativeAmount = request.nativeAmount
+      }
+
+      // Check the minimum:
+      const nativeMin = await request.fromWallet.denominationToNative(
+        quoteReplies[0].result,
+        request.fromCurrencyCode
+      )
+      if (lt(fromNativeAmount, nativeMin)) {
+        throw new SwapBelowLimitError(swapInfo, nativeMin)
+      }
+
+      // Get the address:
+      const sendReply = await call({
+        jsonrpc: '2.0',
+        id: 3,
+        method: 'createTransaction',
+        params: {
+          amount: fromAmount,
+          from: safeFromCurrencyCode,
+          to: safeToCurrencyCode,
+          address: toAddress,
+          extraId: null, // TODO: Do we need this for Monero?
+          refundAddress: fromAddress,
+          refundExtraId: null
+        }
+      })
+      checkReply(sendReply, request)
+      const quoteInfo: QuoteInfo = sendReply.result
+      // Make the transaction:
+      const spendInfo = {
+        currencyCode: request.fromCurrencyCode,
+        spendTargets: [
+          {
+            nativeAmount: fromNativeAmount,
+            publicAddress: quoteInfo.payinAddress,
+            otherParams: {
+              uniqueIdentifier: quoteInfo.payinExtraId
+            }
+          }
+        ]
+      }
+      log('spendInfo', spendInfo)
+      const tx: EdgeTransaction = await request.fromWallet.makeSpend(spendInfo)
+      if (tx.otherParams == null) tx.otherParams = {}
+
+      tx.otherParams.payinAddress = spendInfo.spendTargets[0].publicAddress
+      tx.otherParams.uniqueIdentifier =
+        spendInfo.spendTargets[0].otherParams.uniqueIdentifier
+
+      return makeSwapPluginQuote(
+        request,
+        fromNativeAmount,
+        toNativeAmount,
+        tx,
+        toAddress,
+        'sideshift',
+        true,
+        new Date(Date.now() + expirationMs),
+        quoteInfo.id
+      )
+    }
+  }
+
+  return out
+}