The Handbook for Safe User-to-User Communications in the Sharing Economy

Call it the collaborative, gig, peer-to-peer, or sharing economy — whatever the label, these platforms now operate at global scale. Their growth came with hard questions: regulation, working conditions, fair distribution of value, and whether “sharing” is the right word at all. But for anyone building a marketplace, one challenge sits above the rest: how do you let two strangers communicate safely?

As a communications platform, our role in helping these marketplaces grow comes down to two things — matchmaking between buyers and sellers, and, just as importantly, keeping those interactions secure. This handbook walks through the decisions that shape a marketplace notification and communication system, with practical guidance and input from people who have run peer-to-peer platforms.

Meet the operators

Four marketplace practitioners shared their views throughout this handbook:

Curren Bates — vehicle strategy lead at a micromobility company, and former Director of Marketing at a bike-sharing platform.
Patrick Nangle — CEO of a car-sharing co-operative in British Columbia, and former CEO of a national freight delivery service.
Esther Martos Carrión — UI/UX expert and sharing-economy researcher who has worked with shared-mobility platforms built on blockchain and smart contracts.
Adam Broadway — marketplace expert and CEO of a service for building peer-to-peer and business-to-business marketplaces.

Building trust into a peer-to-peer platform

What makes a peer-to-peer platform work?

Regulators and researchers have boiled marketplace success down to three conditions. A platform tends to work when:

It is liquid — there are enough buyers and sellers active at once.
It enables matchmaking between buyers and sellers in real time.
The transactions taking place on it are safe.

That third point is where communication design matters most. Trust mechanisms — anonymous numbers, email verification, in-app chat, or two-factor authentication over SMS — let you build a safe environment. Which ones you reach for depends entirely on your business model and the kind of experience you are creating.

Different marketplaces create digital trust in different ways, and the mechanism usually scales with the stakes of the exchange. Low-stakes classifieds sites get by with minimal trust signals. Marketplaces built on ratings add reputation but light moderation. Platforms that connect people for high-stakes offline experiences — riding in a stranger’s car, staying in a stranger’s home — invest heavily in trust: ratings, moderation, verified IDs, and insurance.

A useful mental model breaks trust-building into six pillars: declaring information, rating systems, financial commitment from users, encouraging active members, moderated environments through third-party verification, and identity verification through social profiles.

User identification

The hard questions are old ones, sharpened by scale. How do you make sure digital identities reflect real-world ones — and do you even want them to be the same? How do you recreate online the trust that builds naturally face to face? How do you stop someone who behaved badly in one community from showing up again under a new name?

A central decision is how much of a user’s real contact information — phone number, email, social profile, even full name — should be visible to other users.

How much do you really need to know?

Some argue for total transparency, on the theory that mutual exposure keeps everyone honest. In some cases knowing real identities genuinely helps: linking a social profile, or requiring an institutional email address, can reassure users about who they are dealing with, or keep a platform inside a closed community. Letting users sign in with an existing social account and surface mutual connections is a common way to do this.

Storing contact information is a risk in itself

The flip side is that exposed contact information invites abuse. Scammers harvest phone numbers for phishing, and the disinhibition of online interaction can spill into harassment. The issue is one of balance. As one privacy research group put it, platforms have to understand the relationship between identity, anonymity, obscurity, and reputation. They need to give users transparency into how their information is accessed — while offering enough obscurity from other users to protect privacy.

In short: sometimes a buyer and seller should know each other’s real identities, and sometimes they should not. A communications platform is well placed to help you manage that obscurity-versus-identity trade-off — for example, by connecting two people through masked phone numbers so they can talk without ever exchanging personal details.

Newer approaches to identity and reputation continue to evolve, including systems that let a user keep a persistent, verifiable history under a pseudonym, separate from their real-world identity. The general direction is clear: verifiable trust does not always have to mean exposing personal data.

Operator’s view — Esther Martos Carrión

We asked Esther, a UI/UX expert and sharing-economy researcher, for her take on the anonymity-versus-transparency debate.

“This is a constant debate. Personally, I think societies are moving toward transparency. From my research, newer generations are less concerned about privacy than previous ones — people share their personal lives every day, and they enjoy it. You can see how many platforms log users in through existing social or payment accounts, which means platforms are increasingly networked and share information between them. Reputation is starting to move between platforms too, and payments are next. My honest view is that buyers and sellers will keep their social profile as their identity.”

Platform boundaries

Once you have decided how much contact information you actually need, the next question is which channels you use — both to talk to your users (notifications, announcements, events) and to connect users to each other. Before the channels themselves, though, there is a bigger question: should communication between users happen on your platform at all?

Keeping conversations on the platform

For most marketplaces, keeping conversations on-platform is the better choice for three reasons:

It prevents side-stepping. If users can talk freely off-platform, nothing stops them from closing the deal elsewhere to avoid your fees.
It makes conflict resolution possible. Whether the exchange is text or voice, you have access to the record from both sides.
It produces useful signal. Analyzing exchanges helps you spot friction and prioritize what to build next.

That said, locking users in without giving anything back tends to breed frustration. The platforms that do this well make staying on-platform clearly worth it — through insurance, buyer protection, refunds, professional accounts, and similar benefits. A common pattern is to keep the conversation on-platform until the deal is closed, then release contact details so the two parties can coordinate the handoff directly.

The balance between usability and safety

Platform boundaries capture the core tension of any peer-to-peer service: the experience must be as frictionless as possible, while the operator still enforces the checks that prevent scams and abuse and keep users safe.

Operator’s view — Curren Bates

We asked Curren, who has led strategy and marketing at mobility platforms, how he thinks about user communications.

“We encourage communication by whatever means works. The key is that, for the safety of both parties, we don’t allow that exchange to happen until a rental has been booked through the platform — that’s when the protection guarantee kicks in. Beyond that, our in-house messaging exists to give members two things: convenient, instant communication across both email and mobile, and organized record-keeping of their rental conversations, in case anything comes up later. You could keep those records yourself, but it’s more of a headache.”

“Advice for designing a notification system that’s both convenient and safe? Hire good engineers, trust your team, and learn from your mistakes. It sounds cliché, but the market will lead you in the direction you should be heading — so listen.”

Designing your notification system

Enabling real-time matchmaking and safe transactions comes down in large part to choosing the right notification system. Speed and responsiveness are critical on a peer-to-peer platform.

Should you use personal email, in-app messaging, SMS, anonymous phone numbers — or a mix of all of them? Below is a quick read on the trade-offs of the channels marketplaces use most.

Voice

Benefits. Voice is synchronous and personal, and it is efficient for urgent or time-critical conversations. Everyone knows how to make a phone call.
To consider. You can let users swap numbers directly, but that comes with privacy risks. Using a communications API, you can connect two people by phone while keeping their real numbers private and retaining a record of the call.
Recommendation. Calls are the most reliable channel for emergencies and situations that need a real conversation.

SMS

Benefits. SMS has the best open rates, read rates, and time-to-read of any channel, which makes it the strongest pick for time-sensitive alerts.
To consider. As with voice, avoid having users swap numbers directly — use a number-masking service to connect them instead.
Recommendation. SMS is ideal for time-critical alerts. It also works without a smartphone, which can matter depending on your audience.

In-app messaging

Benefits. Users can exchange messages easily and safely, with a degree of privacy maintained until trust is established.
To consider. It is not ideal for time-sensitive messages, and not everyone keeps notifications enabled — plan for alternatives.
Recommendation. Great for synchronous, on-platform conversations; weaker when the exchange is asynchronous.

Email

Benefits. Everyone already has email, and the address itself can support checks (for example, accepting only a given domain).
To consider. Keep users’ email addresses out of public view, and remember that email makes off-platform deals easier.
Recommendation. Convenient but riskier — best reserved mainly for service notifications.

The biggest factor in choosing channels is your audience.

Operator’s view — Adam Broadway

We asked Adam, a marketplace expert and CEO of a marketplace-building platform, which channels he would recommend.

“All of the above — including video calls and third-party integration points, plus customer-service tools. Easy communication between guest and host, buyer and seller, lister and enquirer is critical, including escalation rules for the cases where someone doesn’t follow up.”

“For some interactions, instant messaging is fastest and personal enough to answer simple questions. For others, click-to-call with masked numbers is what’s needed, because the caller wants a deeper conversation than text can handle. Calls made through a communications platform can also be recorded for quality and training, so the operator can review conversations and improve the experience.”

“The platform behind the marketplace also needs a flexible workflow engine, so that ‘you have a new inquiry’ alerts can go out as email, SMS, or in-app — and so reminders escalate across channels if a follow-up doesn’t happen in time. Future-proof your channels with an API layer, so third-party services, CRM, and service-desk tools can all be part of the strategy.”

Control mechanisms that maintain trust

Safety is arguably the heart of the debate around the sharing economy, and the hardest part to get right. Opinions differ on how to keep both buyers and sellers safe, and even on who is responsible. Regulators tend to take a firm line, but it is plainly in the platform’s own interest to reduce the real — and perceived — risk of using the service. There are several ways to do that.

Rating systems

If your providers are individuals, the most valuable thing you can offer is trust and safety. People hesitate to trust strangers: if I lend my car or my drill to someone I have never met, how do I know they won’t damage it or disappear with it? That distrust creates friction in any consumer-to-consumer marketplace — and the marketplace can reduce it by acting as a trusted middleman.

Reputation rating systems have become a cornerstone of these platforms. They do reduce information asymmetry, but they have real limits:

Ratings skew high and toward extremes. People are more likely to review a particularly good or bad experience, and many skip negative reviews to avoid confrontation — which skews the results.
Ratings can be gamed. Fake reviews, positive and negative, are common, and some users avoid honest negative feedback for fear of retaliation.
Experience matters. Newer users are less practiced at reading between the lines of how reviews are written.
Cold starts hurt newcomers. A brand-new user has no track record, which makes it hard to build a reputation and get going.
Reputation milking. Someone about to leave the platform may feel they can trade on their good score without consequences.

Rating systems make a marketplace safer, but they should never be the only trust mechanism you rely on.

Operator’s view — Patrick Nangle

We asked Patrick, CEO of a car-sharing co-operative, how he keeps users safe.

“Our members own the co-operative. The platform simply lets them use the vehicles and contribute to the cost of operations. We ask members to return each vehicle on time, clean, and at least a quarter full of fuel — a courtesy to the next person. Members who don’t are subject to fines, and we count on the next user to flag any issue. The fines are there to encourage better behaviour, not to be profitable. Our updated app includes photo functionality to make reporting easier.”

Platform intervention

A rental marketplace can offer insurance: if an item is stolen or broken, you cover it — but only when the payment ran through your own system. Coverage scales with the value at stake, from high limits for vehicles down to lower limits for lower-value gear like cameras and equipment. Some ridesharing platforms charge a commission and justify it precisely by the insurance they provide.

Many platforms also intervene directly to build and protect trust:

Curate who gets in. Set criteria for who can use the platform — a ride-hailing app, for instance, can require a valid driver’s licence.
Offer refunds. A reliable way to reassure unhappy customers.
Provide insurance. Helps a home-sharing or rental platform feel more secure.

None of these is a complete answer. Curation can’t screen out every bad actor, and refunds and insurance only help after something has gone wrong. Rating systems and platform intervention together still can’t guarantee a perfectly safe experience — which is exactly why communication design and identity controls matter so much.

Parting thoughts

We hope this handbook helps you understand the challenges of direct user-to-user communication and how to handle them. Here are ten takeaways for designing better peer-to-peer communication systems, followed by a last round of advice from the operators.

Ten principles of peer-to-peer communication

Encourage users to keep communication on the platform rather than posting personal phone numbers or emails publicly.
In-app chat and messaging help keep conversations on-platform — for both security and insurance reasons.
High deliverability and open rates make SMS the right call for time-sensitive alerts, on-the-go users, or audiences without smartphones.
Voice is easy to use and the right choice when your platform needs personal, synchronous conversation.
A communications platform can add a valuable layer of privacy or verification through masked numbers and two-factor authentication.
Offer a variety of secure ways for users to communicate.
The higher the stakes of your model, the more trust mechanisms you need.
Transparency versus anonymity is an open debate — what matters is choosing trust mechanisms that fit your platform, whether that’s 2FA ID checks, social sign-in, masked numbers, ratings, or insurance.
Be honest about what your platform does. If your model isn’t really about sharing, don’t market it as such.
Listen to your users, and model your notification system around the channels they already use and the interactions you are building.

Final advice from the operators

Curren Bates. “Trust starts with you, the founder. Show your community how you expect people to treat each other, every day. Maintain exemplary support, especially early on when reviews and backlinks are still scarce. Listen to what your community asks for, take cues from established platforms — and remember there’s no such thing as too much trust.”

Patrick Nangle. “Don’t claim to be part of the sharing economy if you’re not — you’ll lose trust fast if you aren’t authentic. Decide whether your platform genuinely facilitates sharing or is really an exchange for buying and selling. There’s nothing wrong with running a business that facilitates trade for profit; just don’t call it sharing if that’s what it is.”

Adam Broadway. “Communication is the key to success in any relationship, online or off. Give your community more ways to communicate, and don’t worry about them ‘taking the deal off-platform.’ The more conversations you enable — through chat, email, text, phone, or video — the more engagement you’ll have, which leads to more growth and more conversion. Building on top of existing, respected platforms rather than from scratch also helps you avoid security gaps, because you inherit others’ best practices.”

Esther Martos Carrión. “Early on, it’s better to grow through social networks — it brings a lot of visibility and new users, and it’s less invasive than email or SMS. Once the platform is consolidated and has a community, you can move to channels like newsletters and live chat. We also built an internal social space with different channels where our users could ask questions, raise doubts, and connect with peers.”