diff --git a/package-lock.json b/package-lock.json
index df3403e..9c11eb8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@digicatapult/dscp-hyproof-api",
-  "version": "0.7.23",
+  "version": "0.7.24",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@digicatapult/dscp-hyproof-api",
-      "version": "0.7.23",
+      "version": "0.7.24",
       "license": "Apache-2.0",
       "dependencies": {
         "@polkadot/api": "^10.11.2",
diff --git a/package.json b/package.json
index a06976e..e55ea21 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@digicatapult/dscp-hyproof-api",
-  "version": "0.7.23",
+  "version": "0.7.24",
   "description": "An OpenAPI API service for DSCP",
   "main": "src/index.ts",
   "type": "module",
diff --git a/src/controllers/health/__tests__/index.test.ts b/src/controllers/health/__tests__/index.test.ts
index f260df8..0c5cc53 100644
--- a/src/controllers/health/__tests__/index.test.ts
+++ b/src/controllers/health/__tests__/index.test.ts
@@ -1,7 +1,36 @@
 import { expect } from 'chai'
 
-describe('health controller', () => {
-  it('placeholder', () => {
-    expect(1).to.equal(1)
+import Ipfs from '../../../lib/ipfs.js'
+import Database from '../../../lib/db/index.js'
+import Identity from '../../../lib/services/identity.js'
+import ChainNode from '../../../lib/chainNode.js'
+import { HealthController } from '../index.js'
+import { Env } from '../../../env.js'
+import { ServiceWatcher } from '../../../lib/service-watcher/index.js'
+import { ServiceUnavailable } from '../../../lib/error-handler/index.js'
+
+describe('/health', () => {
+  let response: any
+  let controller: HealthController
+
+  const database: Database = new Database()
+  const identity: Identity = new Identity(new Env())
+  const node: ChainNode = new ChainNode(new Env(), database)
+  const ipfs: Ipfs = new Ipfs(new Env())
+  const watcher: ServiceWatcher = new ServiceWatcher(new Env(), node, identity, ipfs)
+
+  before(() => {
+    controller = new HealthController(watcher)
+  })
+
+  describe('get() - GET /', () => {
+    beforeEach(async () => {
+      response = await controller.get().catch((err) => err)
+    })
+
+    it('throws ServiceUnavailable error', () => {
+      expect(response).to.be.instanceOf(ServiceUnavailable)
+      expect(response.code).to.equal(503)
+    })
   })
 })
diff --git a/src/controllers/v1/certificate/__tests__/index.test.ts b/src/controllers/v1/certificate/__tests__/index.test.ts
index d6e01ac..e5bb40a 100644
--- a/src/controllers/v1/certificate/__tests__/index.test.ts
+++ b/src/controllers/v1/certificate/__tests__/index.test.ts
@@ -49,6 +49,10 @@ describe('v1/certificate', () => {
   afterEach(() => {
     stubs.submitRunProcess.resetHistory()
     stubs.prepareRunProcess.resetHistory()
+    stubs.build.resetHistory()
+    stubs.getMemberByAlias.resetHistory()
+    stubs.getSelfAddress.resetHistory()
+    stubs.insert.resetHistory()
   })
 
   describe('postDraft() - POST /', () => {
diff --git a/src/controllers/v1/transaction/__tests__/index.test.ts b/src/controllers/v1/transaction/__tests__/index.test.ts
new file mode 100644
index 0000000..7a32c43
--- /dev/null
+++ b/src/controllers/v1/transaction/__tests__/index.test.ts
@@ -0,0 +1,97 @@
+import { expect } from 'chai'
+import sinon from 'sinon'
+
+import Database from '../../../../lib/db/index.js'
+import { TransactionController } from '../index.js'
+import { TransactionState } from '../../../../models/transaction.js'
+import { NotFound } from '../../../../lib/error-handler/index.js'
+
+export const example = {
+  id: 'transaction-controller-test',
+  api_type: 'certificate',
+  local_id: 'test-cert-1',
+  state: 'submitted',
+  transaction_type: 'initiate_cert',
+}
+
+describe('v1/transaction', () => {
+  let response: any
+  let controller: TransactionController
+
+  const database: Database = new Database()
+  const getStub = sinon.stub(database, 'get' as any).callsFake(() => [{ ...example, id: 'test-1' }, example])
+
+  before(() => {
+    controller = new TransactionController(database)
+  })
+
+  afterEach(() => {
+    getStub.resetHistory()
+  })
+
+  describe('get() - GET /', () => {
+    describe('query by api_type', () => {
+      ;['certificate'].forEach((api_type: any) => {
+        it(` - [${api_type}]`, async () => {
+          response = await controller.get(api_type)
+
+          expect(getStub.lastCall.args[0]).to.equal('transaction')
+          expect(getStub.lastCall.args[1]).to.to.deep.contain({ api_type })
+          expect(response[1]).to.deep.contain(example)
+        })
+      })
+    })
+
+    describe('query by transaction state', () => {
+      ;['submitted', 'inBlock', 'finalised', 'failed'].forEach((state) => {
+        it(`returns transactions based on state - [${state}]`, async () => {
+          response = await controller.get(undefined, state as TransactionState)
+
+          expect(getStub.lastCall.args[0]).to.equal('transaction')
+          expect(response[1]).to.deep.contain(example)
+        })
+      })
+    })
+
+    it('returns transactions by updated_since query param', async () => {
+      response = await controller.get(undefined, undefined, '2024-01-10')
+
+      expect(getStub.lastCall.args[0]).to.equal('transaction')
+    })
+
+    it('returns all transactions without filters', () => {
+      expect(response.length).to.equal(2)
+    })
+  })
+
+  describe('getById() - GET /{id}', () => {
+    beforeEach(async () => {
+      getStub.callsFake((_, args) => [{ ...example, ...args }])
+      response = await controller.getById('test-id').catch((err) => err)
+    })
+
+    describe('if transaction can not be found', () => {
+      beforeEach(async () => {
+        getStub.callsFake(() => [])
+
+        response = await controller.getById('not-found-transaction-id').catch((err) => err)
+      })
+
+      it('throws NotFound error', () => {
+        expect(response).to.be.instanceOf(NotFound)
+        expect(response.code).to.equal(404)
+        expect(response.message).to.equal('transaction [not-found-transaction-id] not found')
+      })
+    })
+
+    it('returns transaction by id', async () => {
+      expect(response).to.deep.contain({
+        id: 'test-id',
+        api_type: 'certificate',
+        local_id: 'test-cert-1',
+        state: 'submitted',
+        transaction_type: 'initiate_cert',
+      })
+    })
+  })
+})
diff --git a/src/controllers/v1/transaction/index.ts b/src/controllers/v1/transaction/index.ts
index 769704b..3cbc29a 100644
--- a/src/controllers/v1/transaction/index.ts
+++ b/src/controllers/v1/transaction/index.ts
@@ -33,7 +33,7 @@ export class TransactionController extends Controller {
   @Response<BadRequest>(400, 'Request was invalid')
   @Response<NotFound>(404, 'Item not found')
   @Get('/')
-  public async getAllTransactions(
+  public async get(
     @Query() api_type?: TransactionApiType,
     @Query() state?: TransactionState,
     @Query() updated_since?: DATE
@@ -53,8 +53,9 @@ export class TransactionController extends Controller {
    */
   @Response<NotFound>(404, 'Item not found')
   @Get('{id}')
-  public async getTransaction(@Path() id: UUID): Promise<GetTransactionResponse> {
-    const transaction = await this.db.get('transaction', { id }).then((transactions) => transactions[0])
+  public async getById(@Path() id: UUID): Promise<GetTransactionResponse> {
+    const [transaction] = await this.db.get('transaction', { id })
+    if (!transaction) throw new NotFound(`transaction [${id}]`)
 
     return transaction
   }