Surmounting P2P Challenges (1/2): Choosing a Notification System


13 min reading time

Several mobile phones with push notifications, SMS, calls and in-app messaging

A two-part guide to help you decide which notification and trust-building mechanisms to use for your peer-to-peer platform

As we wrote about in an earlier article, the Federal Trade Commission has boiled sharing economy platform success factors, (largely applicable to any peer-to-peer platform), down to:

  1. They are “successful if they are liquid”;
  2. if they enable matchmaking between buyers and sellers in real time; and
  3. “if the transactions in them are safe.”

A big part of enabling real time matchmaking and safe transactions is choosing an appropriate notification system. Should you use personal email, in-app messaging, text messaging, anonymous phone numbers? A mixture of all of the above? How can you build trust in your peer-to-peer community? 

To help answer these questions, we’ll first go over advantages and disadvantages to some commonly used notification systems in sharing economy (or peer-to-peer, marketplace…) platforms.  Then, in part II, we’ll quickly expand on this to talk about trust in P2P platforms more generally.

Finally, we spoke with some P2P platform entrepreneurs to get their boots-on-the-ground advice. We’ve included their insights below.

Part I: Notification Systems

Personal Email

Personal email is a simple option to let users get in touch or validate their account.

Screen shot of Spinlister website log in - notification system

Bike rental platform ‘Spinlister’ proposes users validate their account with their email address

Advantages:  Can allow platforms to keep their services within a closed community, i.e. requiring a university or professional email address for validation.  Allows users to receive alerts through a channel they already use, with no added development for the platform.

Keep in mind:  For insurance reasons, many platforms prefer all communication to stay on their platform. Openly listing personal email addresses leaves your users vulnerable to scammers who scrape websites looking for personal information, then use it to send spam or scam emails. Fraud schemes, where fraudsters encourage people to communicate using personal email addresses (off the P2P platform), and then pay for fake goods or services (also off the platform), are on the rise.  Again, transactions that bypass the platform are often not insurable, which can lead to significant monetary loses for the victims.  Finally, many peer-to-peer platforms build a commission system into their business model; swapping contact information may incite users to sidestep this commission fee after they have found each other via the platform.

The common denominators to each racket are that, at some point, the scammer will insist on communicating directly by phone or email, or will steer people to another site to complete the booking process. Then a request will be made for money to be wired to a specific address.  The services basically serve as middlemen, ensuring that everything’s on the up and up. The goal of scammers, therefore, is to get the sites out of the picture and deal one-on-one with potential victims.

David Lazarus, Los Angeles Times, 2016


Recommendation: Personal email addresses are a simple way for users to validate their identity once they join a platform, or to help with “platform curation” if the idea is to keep the community closed.  However, having users post their personal email directly on your platform may not be the best option, due largely to security and insurability concerns. Platforms should also urge users to be very suspicious of people who try too aggressively to communicate with them off the platform via phone or personal email, and never transfer money outside the platform.

In-app Messaging or Email

One way to still allow users to email each other while mitigating security risks is to enable users to communicate directly on your platform, so they don’t divulge their real contact information – at least before they have come to trust another user.  Providing in-app messaging, whether chat or email, has proved a popular solution for many well-known platforms, like TaskRabbit:P2P Platform Taskrabbit explains why communication should stay on their platform - notification system

Aside from putting users in touch, in-app chat via solutions like Olark or similar offer easy ways for customers to get help from the platform’s support team in real time.

Advantages: Allows users to easily and safely communicate using a frequently used channel (email or chat).  Allows for a certain degree of privacy until trust has been established on a one-to-one basis.

Keep in mind: Remember the context of your communication, and how time-sensitive your message is.  (In-app) email can be a good choice for notifications that are not ‘business critical’ (given transactional email’s relatively low open rates – “good” open rates, according to MailJet, are between 30 and 40 percent).

In-app chat is a better choice for more time-sensitive or synchronous communication (i.e. where two users are talking in real time).  However, since in-app messages rely on push notifications, in-app notifications or email notifications to tell a user they have a new message, there will be a risk they aren’t read immediately (due to push notification settings, or no wifi/data).

Airbnb inbox screen shot - notification system

Airbnb uses, among other notification channels, in-app messaging. This helps ensure communication stays on their platform.

For in-app chat designed to put users in touch with your support team, make sure you have a system in place so that there’s always someone able to answer at any given time.

Recommendation: If you decide in-app or email is right for your platform, don’t reinvent the wheel. Plenty of solutions exist to integrate in-app chat, like Hyphenate, that will let you avoid asking your developers to start a project from scratch.

Text Messages

Text messages are an immediate and common way to notify end users of time-sensitive events. They are therefore especially convenient for “business-critical” alerts in the so-called on-demand economy, like when a driver arrives for ride-hailing apps or when your order is outside your door for food delivery.

A text messages from a driver to a rider - notification system

Also, SMS are handy for situations where the end user may be on the move, i.e. not in front of a computer.  Since you don’t need a smartphone, wifi or data to receive a text, they have high deliverability and open rates (90% of text messages are read within the first three seconds of reception, with a final read rate of 98%). Users can also keep a useful record of communication with them in the messaging thread.

However, allowing users to post their personal phone number on a site or swap them with other end users often produces the same problems as with swapping personal email.  Ultimately, this will depend on your business model and the additional trust and safety mechanisms you have put in place.  Some people feel safer with the idea of ‘transparency,’ knowing everyone on a platform has made their real contact info public. Others would prefer a layer of privacy, at least before one-to-one trust can be established with another user.

The advantage of using a CPaaS (Communication Platform as a Service) provider is that a platform can enable text messaging (or voice) communication, but provide dedicated or anonymous numbers to add that extra level of privacy. They can also enable security measures like two-factor authentication, where users validate their phone number and platform account with a shortcode they receive.

A phone verification code on a lock screen - notification system

Spinlister uses 2FA mobile authentication to make sure users are who they say they are

Advantages: High open and read rates.  Good for delivering time-sensitive alerts where the end user might be on the go, or for 2FA security measures.

Keep in mind: While it may be simpler to allow users to swap personal phone numbers, in the long run, this could lead to security issues (phishing, harassment, scams) that could have a negative effect on your brand perception. As BlaBlaCar demonstrated in their Entering the Trust Age report (more below), it’s important for companies to create trust associated with their particular brand, over and above general trust in the sharing economy at large.

Unless you have a very high level of trust within your platform community, or you heavily vet entrants (“platform curation”), integrating a CPaaS API to provide text messaging with dedicated or anonymous numbers can be a good way to bring the convenience of text messages as well as adding an extra level of privacy.

Want to add text messaging with anonymous numbers to your P2P platform?

Check out our API
Uber explains on their FAQ page why they use anonymous numbers - notification system

Uber explains why they use anonymous numbers to put riders and drivers in touch

Recommendation: If you’re running a platform where you need to alert end users in real time, especially in situations where they’re probably not at a computer, SMS is a smart choice.  Keep in mind the demographic of your target audience – if many of them don’t have smartphones, you’ll want to privilege text messages over in-app or email notifications.  For all but the most closed of platforms, using a CPaaS provider’s API to supply anonymous or dedicated phone numbers can add an extra layer of security and avoid unsavoury incidents like harassment, fraud or phishing scams.

Airbnb text message in settings - notification system

Alongside push notifications, Airbnb uses text messages to communicate time-sensitive or critical alerts to their community


For some, chat or text messaging isn’t enough – there needs to be an easy, secure way for users to contact each other vocally. This could be through letting users post their personal phone number, incorporating a click-to-call function, or using a voice API for calling using anonymous numbers.

Advantages: Voice communication is synchronous and personal, and easy for anyone to use.  This makes it a good choice for an emergency notification system, for instance.  As our client Vincent Kraus, CEO of SeniorAdom, an elderly care monitoring system, pointed out, “older generations aren’t always comfortable using mobile apps, reading push notifications or even using SMS.  Phone calls are familiar to everyone, and are the most reassuring and reliable way of communicating in emergency situations.”

Keep in mind: As with personal email and text messages, users who swap their personal phone numbers may be exposing themselves to security risks.  Using a CPaaS provider that can supply anonymous or dedicated phone numbers, as well as the possibility of recording interactions, can add an extra layer of privacy or provide evidence in case of legal disputes.

Advice From our Interviewees

Curren BatesPhoto of Curren Bates from Spinlister - notification system, Director of Marketing at bike rental platform Spinlister, on in-app Messaging:


“We encourage communication by whatever means necessary (text, phone call, carrier pigeon, etc.). It’s simply that, for the safety of both parties, we don’t allow that exchange to take place until after a rental has been booked through Spinlister. That’s when our $10,000 protection guarantee kicks in. Outside of that, our in-house messaging platform is simply there to allow community members 1.) convenient, instant communication across both email and mobile, and 2.) organized record keeping of their rental communications, should anything come up. The latter can be done outside of our system, for sure, but it’s a little bit more of a headache.”

His advice to sharing economy entrepreneurs for building a notification system that is both convenient and safe?

“Hire good devs, trust your team and above all learn from your mistakes. I know it sounds cliche but the market will lead you in the direction you should be heading, so listen.”

Patrick NanglePhoto of Patrick Nangle from Modo - notification system, CEO at car sharing co-op Modo, on what communication channels to use in a peer-to-peer platform: 


“Modo is a member-owned co-operative. We operate a platform that allows our 17,000 members to make use of the co-op’s 500 vehicles.

Members can book a vehicle in a variety of ways, including on-line, using our app, by telephone or by email. Interfaces that allow members to self-serve are the most economical. Nevertheless, wanting to be inclusive and ensure that anyone that wants to carshare can, we offer a variety of means of contact. While most do, not everyone has a smartphone.

We staff our own contact centre to respond to telephone calls and emails. When something happens that needs immediate attention (e.g. car accident; going to return the car late; can’t find the car) it’s important that members can get quickly into contact and receive assistance.”

Esther Martos CarriónPhoto of Esther Carrion from Mealby - notification system, Co-founder and Marketing Manager of Mealby and Sharing Economy PhD researcher, on marketing a sharing economy solution: 

“From my personal experience, I think that at the initial phase it’s better to advertise via social networks, like Facebook, Twitter, etc. This will bring quite a lot of visibility and therefore new users. In my opinion, it’s less invasive than emails, SMS, and other more personal channels. Once the platform is consolidated and has a community of users, you can move to other communication channels, like monthly email newsletters or live chats. We also created an internal social network with different channels in which our users were able to comment, ask about any doubts they had, connect with other peers, etc.”

Adam BroadwayAdam Broadway photo from - notification system, founder of, on which kind of notifications to use for different kinds of platforms:

“Ease of communication between the guest/host, buyer/seller, ‘lister’/enquirer is critical, including escalation rules to handle the exceptional cases when follow-up on the part of the platform doesn’t happen.

For some, instant messaging might be fastest, and able to provide enough of a ‘personal connection’ to answer simple questions. For others, click-to-call with anonymized phone number masking may be needed, as the caller requires a more in-depth conversation than an email or text exchange can efficiently provide.   Calls made via CPaaS providers can also be recorded for ‘training and quality’ purposes, so the marketplace owner is able to review conversations as a means of enhancing the marketplace user experience and FAQ areas of the site.

The platform used to power the marketplace must also provide a flexible workflow engine, so that additional alerts relating to, ‘You have a new inquiry/message’ can be sent as an email, mobile text/sms or as an in-app alert.  These workflow rules should also handle reminders, such that if the communication follow-up has not occurred in a timely manner, escalation through other communication channels can occur to make sure the reminder gets through to the end user.

Future-proof the communications channels by including an API layer, so that 3rd party services such as Olark, Slack, UserVoice, CRM and Service Desk applications can also form part of the overall communication strategy.”

Key Takeaways:

  • It’s advisable for P2P platform users to keep communication on the platform, and not publicly post their personal email or phone number
  • Adding in-app chat/emailing via third party vendors can help ensure communication stays on the platform (for security and insurance reasons)
  • High deliverability and open rates make text messages a good choice for time-sensitive alerts, when your users are on the go, or when your audience may not have a smartphone
  • Voice communication is easy to use, and a good choice if your platform requires personal, synchronous communication
  • CPaaS providers can add an often desirable extra layer of privacy or user verification via anonymous/dedicated numbers and 2-factor authentication

Read part II of our guide for advice on establishing trust in your P2P platform